(function() {
  if (this.__polyfills_originalGlobals == null) {
    this.__polyfills_originalGlobals = {
      define: this.define,
      underscore: this._,
      less: this.less,
      eventemitter2: this.EventEmitter2,
      SelectorSet: this.SelectorSet
    };
  }

  this.define = void 0;

}).call(this);

//     Underscore.js 1.5.2
//     http://underscorejs.org
//     (c) 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
//     Underscore may be freely distributed under the MIT license.

(function() {

  // Baseline setup
  // --------------

  // Establish the root object, `window` in the browser, or `exports` on the server.
  var root = this;

  // Save the previous value of the `_` variable.
  var previousUnderscore = root._;

  // Establish the object that gets returned to break out of a loop iteration.
  var breaker = {};

  // Save bytes in the minified (but not gzipped) version:
  var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;

  // Create quick reference variables for speed access to core prototypes.
  var
    push             = ArrayProto.push,
    slice            = ArrayProto.slice,
    concat           = ArrayProto.concat,
    toString         = ObjProto.toString,
    hasOwnProperty   = ObjProto.hasOwnProperty;

  // All **ECMAScript 5** native function implementations that we hope to use
  // are declared here.
  var
    nativeForEach      = ArrayProto.forEach,
    nativeMap          = ArrayProto.map,
    nativeReduce       = ArrayProto.reduce,
    nativeReduceRight  = ArrayProto.reduceRight,
    nativeFilter       = ArrayProto.filter,
    nativeEvery        = ArrayProto.every,
    nativeSome         = ArrayProto.some,
    nativeIndexOf      = ArrayProto.indexOf,
    nativeLastIndexOf  = ArrayProto.lastIndexOf,
    nativeIsArray      = Array.isArray,
    nativeKeys         = Object.keys,
    nativeBind         = FuncProto.bind;

  // Create a safe reference to the Underscore object for use below.
  var _ = function(obj) {
    if (obj instanceof _) return obj;
    if (!(this instanceof _)) return new _(obj);
    this._wrapped = obj;
  };

  // Export the Underscore object for **Node.js**, with
  // backwards-compatibility for the old `require()` API. If we're in
  // the browser, add `_` as a global object via a string identifier,
  // for Closure Compiler "advanced" mode.
  if (typeof exports !== 'undefined') {
    if (typeof module !== 'undefined' && module.exports) {
      exports = module.exports = _;
    }
    exports._ = _;
  } else {
    root._ = _;
  }

  // Current version.
  _.VERSION = '1.5.2';

  // Collection Functions
  // --------------------

  // The cornerstone, an `each` implementation, aka `forEach`.
  // Handles objects with the built-in `forEach`, arrays, and raw objects.
  // Delegates to **ECMAScript 5**'s native `forEach` if available.
  var each = _.each = _.forEach = function(obj, iterator, context) {
    if (obj == null) return;
    if (nativeForEach && obj.forEach === nativeForEach) {
      obj.forEach(iterator, context);
    } else if (obj.length === +obj.length) {
      for (var i = 0, length = obj.length; i < length; i++) {
        if (iterator.call(context, obj[i], i, obj) === breaker) return;
      }
    } else {
      var keys = _.keys(obj);
      for (var i = 0, length = keys.length; i < length; i++) {
        if (iterator.call(context, obj[keys[i]], keys[i], obj) === breaker) return;
      }
    }
  };

  // Return the results of applying the iterator to each element.
  // Delegates to **ECMAScript 5**'s native `map` if available.
  _.map = _.collect = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
    each(obj, function(value, index, list) {
      results.push(iterator.call(context, value, index, list));
    });
    return results;
  };

  var reduceError = 'Reduce of empty array with no initial value';

  // **Reduce** builds up a single result from a list of values, aka `inject`,
  // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
  _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
    var initial = arguments.length > 2;
    if (obj == null) obj = [];
    if (nativeReduce && obj.reduce === nativeReduce) {
      if (context) iterator = _.bind(iterator, context);
      return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
    }
    each(obj, function(value, index, list) {
      if (!initial) {
        memo = value;
        initial = true;
      } else {
        memo = iterator.call(context, memo, value, index, list);
      }
    });
    if (!initial) throw new TypeError(reduceError);
    return memo;
  };

  // The right-associative version of reduce, also known as `foldr`.
  // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
  _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
    var initial = arguments.length > 2;
    if (obj == null) obj = [];
    if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
      if (context) iterator = _.bind(iterator, context);
      return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
    }
    var length = obj.length;
    if (length !== +length) {
      var keys = _.keys(obj);
      length = keys.length;
    }
    each(obj, function(value, index, list) {
      index = keys ? keys[--length] : --length;
      if (!initial) {
        memo = obj[index];
        initial = true;
      } else {
        memo = iterator.call(context, memo, obj[index], index, list);
      }
    });
    if (!initial) throw new TypeError(reduceError);
    return memo;
  };

  // Return the first value which passes a truth test. Aliased as `detect`.
  _.find = _.detect = function(obj, iterator, context) {
    var result;
    any(obj, function(value, index, list) {
      if (iterator.call(context, value, index, list)) {
        result = value;
        return true;
      }
    });
    return result;
  };

  // Return all the elements that pass a truth test.
  // Delegates to **ECMAScript 5**'s native `filter` if available.
  // Aliased as `select`.
  _.filter = _.select = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
    each(obj, function(value, index, list) {
      if (iterator.call(context, value, index, list)) results.push(value);
    });
    return results;
  };

  // Return all the elements for which a truth test fails.
  _.reject = function(obj, iterator, context) {
    return _.filter(obj, function(value, index, list) {
      return !iterator.call(context, value, index, list);
    }, context);
  };

  // Determine whether all of the elements match a truth test.
  // Delegates to **ECMAScript 5**'s native `every` if available.
  // Aliased as `all`.
  _.every = _.all = function(obj, iterator, context) {
    iterator || (iterator = _.identity);
    var result = true;
    if (obj == null) return result;
    if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
    each(obj, function(value, index, list) {
      if (!(result = result && iterator.call(context, value, index, list))) return breaker;
    });
    return !!result;
  };

  // Determine if at least one element in the object matches a truth test.
  // Delegates to **ECMAScript 5**'s native `some` if available.
  // Aliased as `any`.
  var any = _.some = _.any = function(obj, iterator, context) {
    iterator || (iterator = _.identity);
    var result = false;
    if (obj == null) return result;
    if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
    each(obj, function(value, index, list) {
      if (result || (result = iterator.call(context, value, index, list))) return breaker;
    });
    return !!result;
  };

  // Determine if the array or object contains a given value (using `===`).
  // Aliased as `include`.
  _.contains = _.include = function(obj, target) {
    if (obj == null) return false;
    if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
    return any(obj, function(value) {
      return value === target;
    });
  };

  // Invoke a method (with arguments) on every item in a collection.
  _.invoke = function(obj, method) {
    var args = slice.call(arguments, 2);
    var isFunc = _.isFunction(method);
    return _.map(obj, function(value) {
      return (isFunc ? method : value[method]).apply(value, args);
    });
  };

  // Convenience version of a common use case of `map`: fetching a property.
  _.pluck = function(obj, key) {
    return _.map(obj, function(value){ return value[key]; });
  };

  // Convenience version of a common use case of `filter`: selecting only objects
  // containing specific `key:value` pairs.
  _.where = function(obj, attrs, first) {
    if (_.isEmpty(attrs)) return first ? void 0 : [];
    return _[first ? 'find' : 'filter'](obj, function(value) {
      for (var key in attrs) {
        if (attrs[key] !== value[key]) return false;
      }
      return true;
    });
  };

  // Convenience version of a common use case of `find`: getting the first object
  // containing specific `key:value` pairs.
  _.findWhere = function(obj, attrs) {
    return _.where(obj, attrs, true);
  };

  // Return the maximum element or (element-based computation).
  // Can't optimize arrays of integers longer than 65,535 elements.
  // See [WebKit Bug 80797](https://bugs.webkit.org/show_bug.cgi?id=80797)
  _.max = function(obj, iterator, context) {
    if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
      return Math.max.apply(Math, obj);
    }
    if (!iterator && _.isEmpty(obj)) return -Infinity;
    var result = {computed : -Infinity, value: -Infinity};
    each(obj, function(value, index, list) {
      var computed = iterator ? iterator.call(context, value, index, list) : value;
      computed > result.computed && (result = {value : value, computed : computed});
    });
    return result.value;
  };

  // Return the minimum element (or element-based computation).
  _.min = function(obj, iterator, context) {
    if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
      return Math.min.apply(Math, obj);
    }
    if (!iterator && _.isEmpty(obj)) return Infinity;
    var result = {computed : Infinity, value: Infinity};
    each(obj, function(value, index, list) {
      var computed = iterator ? iterator.call(context, value, index, list) : value;
      computed < result.computed && (result = {value : value, computed : computed});
    });
    return result.value;
  };

  // Shuffle an array, using the modern version of the 
  // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/Fisher–Yates_shuffle).
  _.shuffle = function(obj) {
    var rand;
    var index = 0;
    var shuffled = [];
    each(obj, function(value) {
      rand = _.random(index++);
      shuffled[index - 1] = shuffled[rand];
      shuffled[rand] = value;
    });
    return shuffled;
  };

  // Sample **n** random values from an array.
  // If **n** is not specified, returns a single random element from the array.
  // The internal `guard` argument allows it to work with `map`.
  _.sample = function(obj, n, guard) {
    if (arguments.length < 2 || guard) {
      return obj[_.random(obj.length - 1)];
    }
    return _.shuffle(obj).slice(0, Math.max(0, n));
  };

  // An internal function to generate lookup iterators.
  var lookupIterator = function(value) {
    return _.isFunction(value) ? value : function(obj){ return obj[value]; };
  };

  // Sort the object's values by a criterion produced by an iterator.
  _.sortBy = function(obj, value, context) {
    var iterator = lookupIterator(value);
    return _.pluck(_.map(obj, function(value, index, list) {
      return {
        value: value,
        index: index,
        criteria: iterator.call(context, value, index, list)
      };
    }).sort(function(left, right) {
      var a = left.criteria;
      var b = right.criteria;
      if (a !== b) {
        if (a > b || a === void 0) return 1;
        if (a < b || b === void 0) return -1;
      }
      return left.index - right.index;
    }), 'value');
  };

  // An internal function used for aggregate "group by" operations.
  var group = function(behavior) {
    return function(obj, value, context) {
      var result = {};
      var iterator = value == null ? _.identity : lookupIterator(value);
      each(obj, function(value, index) {
        var key = iterator.call(context, value, index, obj);
        behavior(result, key, value);
      });
      return result;
    };
  };

  // Groups the object's values by a criterion. Pass either a string attribute
  // to group by, or a function that returns the criterion.
  _.groupBy = group(function(result, key, value) {
    (_.has(result, key) ? result[key] : (result[key] = [])).push(value);
  });

  // Indexes the object's values by a criterion, similar to `groupBy`, but for
  // when you know that your index values will be unique.
  _.indexBy = group(function(result, key, value) {
    result[key] = value;
  });

  // Counts instances of an object that group by a certain criterion. Pass
  // either a string attribute to count by, or a function that returns the
  // criterion.
  _.countBy = group(function(result, key) {
    _.has(result, key) ? result[key]++ : result[key] = 1;
  });

  // Use a comparator function to figure out the smallest index at which
  // an object should be inserted so as to maintain order. Uses binary search.
  _.sortedIndex = function(array, obj, iterator, context) {
    iterator = iterator == null ? _.identity : lookupIterator(iterator);
    var value = iterator.call(context, obj);
    var low = 0, high = array.length;
    while (low < high) {
      var mid = (low + high) >>> 1;
      iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid;
    }
    return low;
  };

  // Safely create a real, live array from anything iterable.
  _.toArray = function(obj) {
    if (!obj) return [];
    if (_.isArray(obj)) return slice.call(obj);
    if (obj.length === +obj.length) return _.map(obj, _.identity);
    return _.values(obj);
  };

  // Return the number of elements in an object.
  _.size = function(obj) {
    if (obj == null) return 0;
    return (obj.length === +obj.length) ? obj.length : _.keys(obj).length;
  };

  // Array Functions
  // ---------------

  // Get the first element of an array. Passing **n** will return the first N
  // values in the array. Aliased as `head` and `take`. The **guard** check
  // allows it to work with `_.map`.
  _.first = _.head = _.take = function(array, n, guard) {
    if (array == null) return void 0;
    return (n == null) || guard ? array[0] : slice.call(array, 0, n);
  };

  // Returns everything but the last entry of the array. Especially useful on
  // the arguments object. Passing **n** will return all the values in
  // the array, excluding the last N. The **guard** check allows it to work with
  // `_.map`.
  _.initial = function(array, n, guard) {
    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
  };

  // Get the last element of an array. Passing **n** will return the last N
  // values in the array. The **guard** check allows it to work with `_.map`.
  _.last = function(array, n, guard) {
    if (array == null) return void 0;
    if ((n == null) || guard) {
      return array[array.length - 1];
    } else {
      return slice.call(array, Math.max(array.length - n, 0));
    }
  };

  // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
  // Especially useful on the arguments object. Passing an **n** will return
  // the rest N values in the array. The **guard**
  // check allows it to work with `_.map`.
  _.rest = _.tail = _.drop = function(array, n, guard) {
    return slice.call(array, (n == null) || guard ? 1 : n);
  };

  // Trim out all falsy values from an array.
  _.compact = function(array) {
    return _.filter(array, _.identity);
  };

  // Internal implementation of a recursive `flatten` function.
  var flatten = function(input, shallow, output) {
    if (shallow && _.every(input, _.isArray)) {
      return concat.apply(output, input);
    }
    each(input, function(value) {
      if (_.isArray(value) || _.isArguments(value)) {
        shallow ? push.apply(output, value) : flatten(value, shallow, output);
      } else {
        output.push(value);
      }
    });
    return output;
  };

  // Flatten out an array, either recursively (by default), or just one level.
  _.flatten = function(array, shallow) {
    return flatten(array, shallow, []);
  };

  // Return a version of the array that does not contain the specified value(s).
  _.without = function(array) {
    return _.difference(array, slice.call(arguments, 1));
  };

  // Produce a duplicate-free version of the array. If the array has already
  // been sorted, you have the option of using a faster algorithm.
  // Aliased as `unique`.
  _.uniq = _.unique = function(array, isSorted, iterator, context) {
    if (_.isFunction(isSorted)) {
      context = iterator;
      iterator = isSorted;
      isSorted = false;
    }
    var initial = iterator ? _.map(array, iterator, context) : array;
    var results = [];
    var seen = [];
    each(initial, function(value, index) {
      if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) {
        seen.push(value);
        results.push(array[index]);
      }
    });
    return results;
  };

  // Produce an array that contains the union: each distinct element from all of
  // the passed-in arrays.
  _.union = function() {
    return _.uniq(_.flatten(arguments, true));
  };

  // Produce an array that contains every item shared between all the
  // passed-in arrays.
  _.intersection = function(array) {
    var rest = slice.call(arguments, 1);
    return _.filter(_.uniq(array), function(item) {
      return _.every(rest, function(other) {
        return _.indexOf(other, item) >= 0;
      });
    });
  };

  // Take the difference between one array and a number of other arrays.
  // Only the elements present in just the first array will remain.
  _.difference = function(array) {
    var rest = concat.apply(ArrayProto, slice.call(arguments, 1));
    return _.filter(array, function(value){ return !_.contains(rest, value); });
  };

  // Zip together multiple lists into a single array -- elements that share
  // an index go together.
  _.zip = function() {
    var length = _.max(_.pluck(arguments, "length").concat(0));
    var results = new Array(length);
    for (var i = 0; i < length; i++) {
      results[i] = _.pluck(arguments, '' + i);
    }
    return results;
  };

  // Converts lists into objects. Pass either a single array of `[key, value]`
  // pairs, or two parallel arrays of the same length -- one of keys, and one of
  // the corresponding values.
  _.object = function(list, values) {
    if (list == null) return {};
    var result = {};
    for (var i = 0, length = list.length; i < length; i++) {
      if (values) {
        result[list[i]] = values[i];
      } else {
        result[list[i][0]] = list[i][1];
      }
    }
    return result;
  };

  // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
  // we need this function. Return the position of the first occurrence of an
  // item in an array, or -1 if the item is not included in the array.
  // Delegates to **ECMAScript 5**'s native `indexOf` if available.
  // If the array is large and already in sort order, pass `true`
  // for **isSorted** to use binary search.
  _.indexOf = function(array, item, isSorted) {
    if (array == null) return -1;
    var i = 0, length = array.length;
    if (isSorted) {
      if (typeof isSorted == 'number') {
        i = (isSorted < 0 ? Math.max(0, length + isSorted) : isSorted);
      } else {
        i = _.sortedIndex(array, item);
        return array[i] === item ? i : -1;
      }
    }
    if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted);
    for (; i < length; i++) if (array[i] === item) return i;
    return -1;
  };

  // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
  _.lastIndexOf = function(array, item, from) {
    if (array == null) return -1;
    var hasIndex = from != null;
    if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) {
      return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item);
    }
    var i = (hasIndex ? from : array.length);
    while (i--) if (array[i] === item) return i;
    return -1;
  };

  // Generate an integer Array containing an arithmetic progression. A port of
  // the native Python `range()` function. See
  // [the Python documentation](http://docs.python.org/library/functions.html#range).
  _.range = function(start, stop, step) {
    if (arguments.length <= 1) {
      stop = start || 0;
      start = 0;
    }
    step = arguments[2] || 1;

    var length = Math.max(Math.ceil((stop - start) / step), 0);
    var idx = 0;
    var range = new Array(length);

    while(idx < length) {
      range[idx++] = start;
      start += step;
    }

    return range;
  };

  // Function (ahem) Functions
  // ------------------

  // Reusable constructor function for prototype setting.
  var ctor = function(){};

  // Create a function bound to a given object (assigning `this`, and arguments,
  // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
  // available.
  _.bind = function(func, context) {
    var args, bound;
    if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
    if (!_.isFunction(func)) throw new TypeError;
    args = slice.call(arguments, 2);
    return bound = function() {
      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
      ctor.prototype = func.prototype;
      var self = new ctor;
      ctor.prototype = null;
      var result = func.apply(self, args.concat(slice.call(arguments)));
      if (Object(result) === result) return result;
      return self;
    };
  };

  // Partially apply a function by creating a version that has had some of its
  // arguments pre-filled, without changing its dynamic `this` context.
  _.partial = function(func) {
    var args = slice.call(arguments, 1);
    return function() {
      return func.apply(this, args.concat(slice.call(arguments)));
    };
  };

  // Bind all of an object's methods to that object. Useful for ensuring that
  // all callbacks defined on an object belong to it.
  _.bindAll = function(obj) {
    var funcs = slice.call(arguments, 1);
    if (funcs.length === 0) throw new Error("bindAll must be passed function names");
    each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
    return obj;
  };

  // Memoize an expensive function by storing its results.
  _.memoize = function(func, hasher) {
    var memo = {};
    hasher || (hasher = _.identity);
    return function() {
      var key = hasher.apply(this, arguments);
      return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
    };
  };

  // Delays a function for the given number of milliseconds, and then calls
  // it with the arguments supplied.
  _.delay = function(func, wait) {
    var args = slice.call(arguments, 2);
    return setTimeout(function(){ return func.apply(null, args); }, wait);
  };

  // Defers a function, scheduling it to run after the current call stack has
  // cleared.
  _.defer = function(func) {
    return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
  };

  // Returns a function, that, when invoked, will only be triggered at most once
  // during a given window of time. Normally, the throttled function will run
  // as much as it can, without ever going more than once per `wait` duration;
  // but if you'd like to disable the execution on the leading edge, pass
  // `{leading: false}`. To disable execution on the trailing edge, ditto.
  _.throttle = function(func, wait, options) {
    var context, args, result;
    var timeout = null;
    var previous = 0;
    options || (options = {});
    var later = function() {
      previous = options.leading === false ? 0 : new Date;
      timeout = null;
      result = func.apply(context, args);
    };
    return function() {
      var now = new Date;
      if (!previous && options.leading === false) previous = now;
      var remaining = wait - (now - previous);
      context = this;
      args = arguments;
      if (remaining <= 0) {
        clearTimeout(timeout);
        timeout = null;
        previous = now;
        result = func.apply(context, args);
      } else if (!timeout && options.trailing !== false) {
        timeout = setTimeout(later, remaining);
      }
      return result;
    };
  };

  // Returns a function, that, as long as it continues to be invoked, will not
  // be triggered. The function will be called after it stops being called for
  // N milliseconds. If `immediate` is passed, trigger the function on the
  // leading edge, instead of the trailing.
  _.debounce = function(func, wait, immediate) {
    var timeout, args, context, timestamp, result;
    return function() {
      context = this;
      args = arguments;
      timestamp = new Date();
      var later = function() {
        var last = (new Date()) - timestamp;
        if (last < wait) {
          timeout = setTimeout(later, wait - last);
        } else {
          timeout = null;
          if (!immediate) result = func.apply(context, args);
        }
      };
      var callNow = immediate && !timeout;
      if (!timeout) {
        timeout = setTimeout(later, wait);
      }
      if (callNow) result = func.apply(context, args);
      return result;
    };
  };

  // Returns a function that will be executed at most one time, no matter how
  // often you call it. Useful for lazy initialization.
  _.once = function(func) {
    var ran = false, memo;
    return function() {
      if (ran) return memo;
      ran = true;
      memo = func.apply(this, arguments);
      func = null;
      return memo;
    };
  };

  // Returns the first function passed as an argument to the second,
  // allowing you to adjust arguments, run code before and after, and
  // conditionally execute the original function.
  _.wrap = function(func, wrapper) {
    return function() {
      var args = [func];
      push.apply(args, arguments);
      return wrapper.apply(this, args);
    };
  };

  // Returns a function that is the composition of a list of functions, each
  // consuming the return value of the function that follows.
  _.compose = function() {
    var funcs = arguments;
    return function() {
      var args = arguments;
      for (var i = funcs.length - 1; i >= 0; i--) {
        args = [funcs[i].apply(this, args)];
      }
      return args[0];
    };
  };

  // Returns a function that will only be executed after being called N times.
  _.after = function(times, func) {
    return function() {
      if (--times < 1) {
        return func.apply(this, arguments);
      }
    };
  };

  // Object Functions
  // ----------------

  // Retrieve the names of an object's properties.
  // Delegates to **ECMAScript 5**'s native `Object.keys`
  _.keys = nativeKeys || function(obj) {
    if (obj !== Object(obj)) throw new TypeError('Invalid object');
    var keys = [];
    for (var key in obj) if (_.has(obj, key)) keys.push(key);
    return keys;
  };

  // Retrieve the values of an object's properties.
  _.values = function(obj) {
    var keys = _.keys(obj);
    var length = keys.length;
    var values = new Array(length);
    for (var i = 0; i < length; i++) {
      values[i] = obj[keys[i]];
    }
    return values;
  };

  // Convert an object into a list of `[key, value]` pairs.
  _.pairs = function(obj) {
    var keys = _.keys(obj);
    var length = keys.length;
    var pairs = new Array(length);
    for (var i = 0; i < length; i++) {
      pairs[i] = [keys[i], obj[keys[i]]];
    }
    return pairs;
  };

  // Invert the keys and values of an object. The values must be serializable.
  _.invert = function(obj) {
    var result = {};
    var keys = _.keys(obj);
    for (var i = 0, length = keys.length; i < length; i++) {
      result[obj[keys[i]]] = keys[i];
    }
    return result;
  };

  // Return a sorted list of the function names available on the object.
  // Aliased as `methods`
  _.functions = _.methods = function(obj) {
    var names = [];
    for (var key in obj) {
      if (_.isFunction(obj[key])) names.push(key);
    }
    return names.sort();
  };

  // Extend a given object with all the properties in passed-in object(s).
  _.extend = function(obj) {
    each(slice.call(arguments, 1), function(source) {
      if (source) {
        for (var prop in source) {
          obj[prop] = source[prop];
        }
      }
    });
    return obj;
  };

  // Return a copy of the object only containing the whitelisted properties.
  _.pick = function(obj) {
    var copy = {};
    var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
    each(keys, function(key) {
      if (key in obj) copy[key] = obj[key];
    });
    return copy;
  };

   // Return a copy of the object without the blacklisted properties.
  _.omit = function(obj) {
    var copy = {};
    var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
    for (var key in obj) {
      if (!_.contains(keys, key)) copy[key] = obj[key];
    }
    return copy;
  };

  // Fill in a given object with default properties.
  _.defaults = function(obj) {
    each(slice.call(arguments, 1), function(source) {
      if (source) {
        for (var prop in source) {
          if (obj[prop] === void 0) obj[prop] = source[prop];
        }
      }
    });
    return obj;
  };

  // Create a (shallow-cloned) duplicate of an object.
  _.clone = function(obj) {
    if (!_.isObject(obj)) return obj;
    return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
  };

  // Invokes interceptor with the obj, and then returns obj.
  // The primary purpose of this method is to "tap into" a method chain, in
  // order to perform operations on intermediate results within the chain.
  _.tap = function(obj, interceptor) {
    interceptor(obj);
    return obj;
  };

  // Internal recursive comparison function for `isEqual`.
  var eq = function(a, b, aStack, bStack) {
    // Identical objects are equal. `0 === -0`, but they aren't identical.
    // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
    if (a === b) return a !== 0 || 1 / a == 1 / b;
    // A strict comparison is necessary because `null == undefined`.
    if (a == null || b == null) return a === b;
    // Unwrap any wrapped objects.
    if (a instanceof _) a = a._wrapped;
    if (b instanceof _) b = b._wrapped;
    // Compare `[[Class]]` names.
    var className = toString.call(a);
    if (className != toString.call(b)) return false;
    switch (className) {
      // Strings, numbers, dates, and booleans are compared by value.
      case '[object String]':
        // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
        // equivalent to `new String("5")`.
        return a == String(b);
      case '[object Number]':
        // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
        // other numeric values.
        return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
      case '[object Date]':
      case '[object Boolean]':
        // Coerce dates and booleans to numeric primitive values. Dates are compared by their
        // millisecond representations. Note that invalid dates with millisecond representations
        // of `NaN` are not equivalent.
        return +a == +b;
      // RegExps are compared by their source patterns and flags.
      case '[object RegExp]':
        return a.source == b.source &&
               a.global == b.global &&
               a.multiline == b.multiline &&
               a.ignoreCase == b.ignoreCase;
    }
    if (typeof a != 'object' || typeof b != 'object') return false;
    // Assume equality for cyclic structures. The algorithm for detecting cyclic
    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
    var length = aStack.length;
    while (length--) {
      // Linear search. Performance is inversely proportional to the number of
      // unique nested structures.
      if (aStack[length] == a) return bStack[length] == b;
    }
    // Objects with different constructors are not equivalent, but `Object`s
    // from different frames are.
    var aCtor = a.constructor, bCtor = b.constructor;
    if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
                             _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
      return false;
    }
    // Add the first object to the stack of traversed objects.
    aStack.push(a);
    bStack.push(b);
    var size = 0, result = true;
    // Recursively compare objects and arrays.
    if (className == '[object Array]') {
      // Compare array lengths to determine if a deep comparison is necessary.
      size = a.length;
      result = size == b.length;
      if (result) {
        // Deep compare the contents, ignoring non-numeric properties.
        while (size--) {
          if (!(result = eq(a[size], b[size], aStack, bStack))) break;
        }
      }
    } else {
      // Deep compare objects.
      for (var key in a) {
        if (_.has(a, key)) {
          // Count the expected number of properties.
          size++;
          // Deep compare each member.
          if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break;
        }
      }
      // Ensure that both objects contain the same number of properties.
      if (result) {
        for (key in b) {
          if (_.has(b, key) && !(size--)) break;
        }
        result = !size;
      }
    }
    // Remove the first object from the stack of traversed objects.
    aStack.pop();
    bStack.pop();
    return result;
  };

  // Perform a deep comparison to check if two objects are equal.
  _.isEqual = function(a, b) {
    return eq(a, b, [], []);
  };

  // Is a given array, string, or object empty?
  // An "empty" object has no enumerable own-properties.
  _.isEmpty = function(obj) {
    if (obj == null) return true;
    if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
    for (var key in obj) if (_.has(obj, key)) return false;
    return true;
  };

  // Is a given value a DOM element?
  _.isElement = function(obj) {
    return !!(obj && obj.nodeType === 1);
  };

  // Is a given value an array?
  // Delegates to ECMA5's native Array.isArray
  _.isArray = nativeIsArray || function(obj) {
    return toString.call(obj) == '[object Array]';
  };

  // Is a given variable an object?
  _.isObject = function(obj) {
    return obj === Object(obj);
  };

  // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp.
  each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) {
    _['is' + name] = function(obj) {
      return toString.call(obj) == '[object ' + name + ']';
    };
  });

  // Define a fallback version of the method in browsers (ahem, IE), where
  // there isn't any inspectable "Arguments" type.
  if (!_.isArguments(arguments)) {
    _.isArguments = function(obj) {
      return !!(obj && _.has(obj, 'callee'));
    };
  }

  // Optimize `isFunction` if appropriate.
  if (typeof (/./) !== 'function') {
    _.isFunction = function(obj) {
      return typeof obj === 'function';
    };
  }

  // Is a given object a finite number?
  _.isFinite = function(obj) {
    return isFinite(obj) && !isNaN(parseFloat(obj));
  };

  // Is the given value `NaN`? (NaN is the only number which does not equal itself).
  _.isNaN = function(obj) {
    return _.isNumber(obj) && obj != +obj;
  };

  // Is a given value a boolean?
  _.isBoolean = function(obj) {
    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
  };

  // Is a given value equal to null?
  _.isNull = function(obj) {
    return obj === null;
  };

  // Is a given variable undefined?
  _.isUndefined = function(obj) {
    return obj === void 0;
  };

  // Shortcut function for checking if an object has a given property directly
  // on itself (in other words, not on a prototype).
  _.has = function(obj, key) {
    return hasOwnProperty.call(obj, key);
  };

  // Utility Functions
  // -----------------

  // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
  // previous owner. Returns a reference to the Underscore object.
  _.noConflict = function() {
    root._ = previousUnderscore;
    return this;
  };

  // Keep the identity function around for default iterators.
  _.identity = function(value) {
    return value;
  };

  // Run a function **n** times.
  _.times = function(n, iterator, context) {
    var accum = Array(Math.max(0, n));
    for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i);
    return accum;
  };

  // Return a random integer between min and max (inclusive).
  _.random = function(min, max) {
    if (max == null) {
      max = min;
      min = 0;
    }
    return min + Math.floor(Math.random() * (max - min + 1));
  };

  // List of HTML entities for escaping.
  var entityMap = {
    escape: {
      '&': '&amp;',
      '<': '&lt;',
      '>': '&gt;',
      '"': '&quot;',
      "'": '&#x27;'
    }
  };
  entityMap.unescape = _.invert(entityMap.escape);

  // Regexes containing the keys and values listed immediately above.
  var entityRegexes = {
    escape:   new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'),
    unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g')
  };

  // Functions for escaping and unescaping strings to/from HTML interpolation.
  _.each(['escape', 'unescape'], function(method) {
    _[method] = function(string) {
      if (string == null) return '';
      return ('' + string).replace(entityRegexes[method], function(match) {
        return entityMap[method][match];
      });
    };
  });

  // If the value of the named `property` is a function then invoke it with the
  // `object` as context; otherwise, return it.
  _.result = function(object, property) {
    if (object == null) return void 0;
    var value = object[property];
    return _.isFunction(value) ? value.call(object) : value;
  };

  // Add your own custom functions to the Underscore object.
  _.mixin = function(obj) {
    each(_.functions(obj), function(name) {
      var func = _[name] = obj[name];
      _.prototype[name] = function() {
        var args = [this._wrapped];
        push.apply(args, arguments);
        return result.call(this, func.apply(_, args));
      };
    });
  };

  // Generate a unique integer id (unique within the entire client session).
  // Useful for temporary DOM ids.
  var idCounter = 0;
  _.uniqueId = function(prefix) {
    var id = ++idCounter + '';
    return prefix ? prefix + id : id;
  };

  // By default, Underscore uses ERB-style template delimiters, change the
  // following template settings to use alternative delimiters.
  _.templateSettings = {
    evaluate    : /<%([\s\S]+?)%>/g,
    interpolate : /<%=([\s\S]+?)%>/g,
    escape      : /<%-([\s\S]+?)%>/g
  };

  // When customizing `templateSettings`, if you don't want to define an
  // interpolation, evaluation or escaping regex, we need one that is
  // guaranteed not to match.
  var noMatch = /(.)^/;

  // Certain characters need to be escaped so that they can be put into a
  // string literal.
  var escapes = {
    "'":      "'",
    '\\':     '\\',
    '\r':     'r',
    '\n':     'n',
    '\t':     't',
    '\u2028': 'u2028',
    '\u2029': 'u2029'
  };

  var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;

  // JavaScript micro-templating, similar to John Resig's implementation.
  // Underscore templating handles arbitrary delimiters, preserves whitespace,
  // and correctly escapes quotes within interpolated code.
  _.template = function(text, data, settings) {
    var render;
    settings = _.defaults({}, settings, _.templateSettings);

    // Combine delimiters into one regular expression via alternation.
    var matcher = new RegExp([
      (settings.escape || noMatch).source,
      (settings.interpolate || noMatch).source,
      (settings.evaluate || noMatch).source
    ].join('|') + '|$', 'g');

    // Compile the template source, escaping string literals appropriately.
    var index = 0;
    var source = "__p+='";
    text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
      source += text.slice(index, offset)
        .replace(escaper, function(match) { return '\\' + escapes[match]; });

      if (escape) {
        source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
      }
      if (interpolate) {
        source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
      }
      if (evaluate) {
        source += "';\n" + evaluate + "\n__p+='";
      }
      index = offset + match.length;
      return match;
    });
    source += "';\n";

    // If a variable is not specified, place data values in local scope.
    if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';

    source = "var __t,__p='',__j=Array.prototype.join," +
      "print=function(){__p+=__j.call(arguments,'');};\n" +
      source + "return __p;\n";

    try {
      render = new Function(settings.variable || 'obj', '_', source);
    } catch (e) {
      e.source = source;
      throw e;
    }

    if (data) return render(data, _);
    var template = function(data) {
      return render.call(this, data, _);
    };

    // Provide the compiled function source as a convenience for precompilation.
    template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';

    return template;
  };

  // Add a "chain" function, which will delegate to the wrapper.
  _.chain = function(obj) {
    return _(obj).chain();
  };

  // OOP
  // ---------------
  // If Underscore is called as a function, it returns a wrapped object that
  // can be used OO-style. This wrapper holds altered versions of all the
  // underscore functions. Wrapped objects may be chained.

  // Helper function to continue chaining intermediate results.
  var result = function(obj) {
    return this._chain ? _(obj).chain() : obj;
  };

  // Add all of the Underscore functions to the wrapper object.
  _.mixin(_);

  // Add all mutator Array functions to the wrapper.
  each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
    var method = ArrayProto[name];
    _.prototype[name] = function() {
      var obj = this._wrapped;
      method.apply(obj, arguments);
      if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0];
      return result.call(this, obj);
    };
  });

  // Add all accessor Array functions to the wrapper.
  each(['concat', 'join', 'slice'], function(name) {
    var method = ArrayProto[name];
    _.prototype[name] = function() {
      return result.call(this, method.apply(this._wrapped, arguments));
    };
  });

  _.extend(_.prototype, {

    // Start chaining a wrapped Underscore object.
    chain: function() {
      this._chain = true;
      return this;
    },

    // Extracts the result from a wrapped and chained object.
    value: function() {
      return this._wrapped;
    }

  });

}).call(this);

/*!
 * Sizzle CSS Selector Engine v1.10.19
 * http://sizzlejs.com/
 *
 * Copyright 2013 jQuery Foundation, Inc. and other contributors
 * Released under the MIT license
 * http://jquery.org/license
 *
 * Date: 2014-04-18
 */
(function( window ) {

var i,
	support,
	Expr,
	getText,
	isXML,
	tokenize,
	compile,
	select,
	outermostContext,
	sortInput,
	hasDuplicate,

	// Local document vars
	setDocument,
	document,
	docElem,
	documentIsHTML,
	rbuggyQSA,
	rbuggyMatches,
	matches,
	contains,

	// Instance-specific data
	expando = "sizzle" + -(new Date()),
	preferredDoc = window.document,
	dirruns = 0,
	done = 0,
	classCache = createCache(),
	tokenCache = createCache(),
	compilerCache = createCache(),
	sortOrder = function( a, b ) {
		if ( a === b ) {
			hasDuplicate = true;
		}
		return 0;
	},

	// General-purpose constants
	strundefined = typeof undefined,
	MAX_NEGATIVE = 1 << 31,

	// Instance methods
	hasOwn = ({}).hasOwnProperty,
	arr = [],
	pop = arr.pop,
	push_native = arr.push,
	push = arr.push,
	slice = arr.slice,
	// Use a stripped-down indexOf if we can't use a native one
	indexOf = arr.indexOf || function( elem ) {
		var i = 0,
			len = this.length;
		for ( ; i < len; i++ ) {
			if ( this[i] === elem ) {
				return i;
			}
		}
		return -1;
	},

	booleans = "checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped",

	// Regular expressions

	// Whitespace characters http://www.w3.org/TR/css3-selectors/#whitespace
	whitespace = "[\\x20\\t\\r\\n\\f]",
	// http://www.w3.org/TR/css3-syntax/#characters
	characterEncoding = "(?:\\\\.|[\\w-]|[^\\x00-\\xa0])+",

	// Loosely modeled on CSS identifier characters
	// An unquoted value should be a CSS identifier http://www.w3.org/TR/css3-selectors/#attribute-selectors
	// Proper syntax: http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
	identifier = characterEncoding.replace( "w", "w#" ),

	// Attribute selectors: http://www.w3.org/TR/selectors/#attribute-selectors
	attributes = "\\[" + whitespace + "*(" + characterEncoding + ")(?:" + whitespace +
		// Operator (capture 2)
		"*([*^$|!~]?=)" + whitespace +
		// "Attribute values must be CSS identifiers [capture 5] or strings [capture 3 or capture 4]"
		"*(?:'((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\"|(" + identifier + "))|)" + whitespace +
		"*\\]",

	pseudos = ":(" + characterEncoding + ")(?:\\((" +
		// To reduce the number of selectors needing tokenize in the preFilter, prefer arguments:
		// 1. quoted (capture 3; capture 4 or capture 5)
		"('((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\")|" +
		// 2. simple (capture 6)
		"((?:\\\\.|[^\\\\()[\\]]|" + attributes + ")*)|" +
		// 3. anything else (capture 2)
		".*" +
		")\\)|)",

	// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
	rtrim = new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" ),

	rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
	rcombinators = new RegExp( "^" + whitespace + "*([>+~]|" + whitespace + ")" + whitespace + "*" ),

	rattributeQuotes = new RegExp( "=" + whitespace + "*([^\\]'\"]*?)" + whitespace + "*\\]", "g" ),

	rpseudo = new RegExp( pseudos ),
	ridentifier = new RegExp( "^" + identifier + "$" ),

	matchExpr = {
		"ID": new RegExp( "^#(" + characterEncoding + ")" ),
		"CLASS": new RegExp( "^\\.(" + characterEncoding + ")" ),
		"TAG": new RegExp( "^(" + characterEncoding.replace( "w", "w*" ) + ")" ),
		"ATTR": new RegExp( "^" + attributes ),
		"PSEUDO": new RegExp( "^" + pseudos ),
		"CHILD": new RegExp( "^:(only|first|last|nth|nth-last)-(child|of-type)(?:\\(" + whitespace +
			"*(even|odd|(([+-]|)(\\d*)n|)" + whitespace + "*(?:([+-]|)" + whitespace +
			"*(\\d+)|))" + whitespace + "*\\)|)", "i" ),
		"bool": new RegExp( "^(?:" + booleans + ")$", "i" ),
		// For use in libraries implementing .is()
		// We use this for POS matching in `select`
		"needsContext": new RegExp( "^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" +
			whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
	},

	rinputs = /^(?:input|select|textarea|button)$/i,
	rheader = /^h\d$/i,

	rnative = /^[^{]+\{\s*\[native \w/,

	// Easily-parseable/retrievable ID or TAG or CLASS selectors
	rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,

	rsibling = /[+~]/,
	rescape = /'|\\/g,

	// CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
	runescape = new RegExp( "\\\\([\\da-f]{1,6}" + whitespace + "?|(" + whitespace + ")|.)", "ig" ),
	funescape = function( _, escaped, escapedWhitespace ) {
		var high = "0x" + escaped - 0x10000;
		// NaN means non-codepoint
		// Support: Firefox<24
		// Workaround erroneous numeric interpretation of +"0x"
		return high !== high || escapedWhitespace ?
			escaped :
			high < 0 ?
				// BMP codepoint
				String.fromCharCode( high + 0x10000 ) :
				// Supplemental Plane codepoint (surrogate pair)
				String.fromCharCode( high >> 10 | 0xD800, high & 0x3FF | 0xDC00 );
	};

// Optimize for push.apply( _, NodeList )
try {
	push.apply(
		(arr = slice.call( preferredDoc.childNodes )),
		preferredDoc.childNodes
	);
	// Support: Android<4.0
	// Detect silently failing push.apply
	arr[ preferredDoc.childNodes.length ].nodeType;
} catch ( e ) {
	push = { apply: arr.length ?

		// Leverage slice if possible
		function( target, els ) {
			push_native.apply( target, slice.call(els) );
		} :

		// Support: IE<9
		// Otherwise append directly
		function( target, els ) {
			var j = target.length,
				i = 0;
			// Can't trust NodeList.length
			while ( (target[j++] = els[i++]) ) {}
			target.length = j - 1;
		}
	};
}

function Sizzle( selector, context, results, seed ) {
	var match, elem, m, nodeType,
		// QSA vars
		i, groups, old, nid, newContext, newSelector;

	if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
		setDocument( context );
	}

	context = context || document;
	results = results || [];

	if ( !selector || typeof selector !== "string" ) {
		return results;
	}

	if ( (nodeType = context.nodeType) !== 1 && nodeType !== 9 ) {
		return [];
	}

	if ( documentIsHTML && !seed ) {

		// Shortcuts
		if ( (match = rquickExpr.exec( selector )) ) {
			// Speed-up: Sizzle("#ID")
			if ( (m = match[1]) ) {
				if ( nodeType === 9 ) {
					elem = context.getElementById( m );
					// Check parentNode to catch when Blackberry 4.6 returns
					// nodes that are no longer in the document (jQuery #6963)
					if ( elem && elem.parentNode ) {
						// Handle the case where IE, Opera, and Webkit return items
						// by name instead of ID
						if ( elem.id === m ) {
							results.push( elem );
							return results;
						}
					} else {
						return results;
					}
				} else {
					// Context is not a document
					if ( context.ownerDocument && (elem = context.ownerDocument.getElementById( m )) &&
						contains( context, elem ) && elem.id === m ) {
						results.push( elem );
						return results;
					}
				}

			// Speed-up: Sizzle("TAG")
			} else if ( match[2] ) {
				push.apply( results, context.getElementsByTagName( selector ) );
				return results;

			// Speed-up: Sizzle(".CLASS")
			} else if ( (m = match[3]) && support.getElementsByClassName && context.getElementsByClassName ) {
				push.apply( results, context.getElementsByClassName( m ) );
				return results;
			}
		}

		// QSA path
		if ( support.qsa && (!rbuggyQSA || !rbuggyQSA.test( selector )) ) {
			nid = old = expando;
			newContext = context;
			newSelector = nodeType === 9 && selector;

			// qSA works strangely on Element-rooted queries
			// We can work around this by specifying an extra ID on the root
			// and working up from there (Thanks to Andrew Dupont for the technique)
			// IE 8 doesn't work on object elements
			if ( nodeType === 1 && context.nodeName.toLowerCase() !== "object" ) {
				groups = tokenize( selector );

				if ( (old = context.getAttribute("id")) ) {
					nid = old.replace( rescape, "\\$&" );
				} else {
					context.setAttribute( "id", nid );
				}
				nid = "[id='" + nid + "'] ";

				i = groups.length;
				while ( i-- ) {
					groups[i] = nid + toSelector( groups[i] );
				}
				newContext = rsibling.test( selector ) && testContext( context.parentNode ) || context;
				newSelector = groups.join(",");
			}

			if ( newSelector ) {
				try {
					push.apply( results,
						newContext.querySelectorAll( newSelector )
					);
					return results;
				} catch(qsaError) {
				} finally {
					if ( !old ) {
						context.removeAttribute("id");
					}
				}
			}
		}
	}

	// All others
	return select( selector.replace( rtrim, "$1" ), context, results, seed );
}

/**
 * Create key-value caches of limited size
 * @returns {Function(string, Object)} Returns the Object data after storing it on itself with
 *	property name the (space-suffixed) string and (if the cache is larger than Expr.cacheLength)
 *	deleting the oldest entry
 */
function createCache() {
	var keys = [];

	function cache( key, value ) {
		// Use (key + " ") to avoid collision with native prototype properties (see Issue #157)
		if ( keys.push( key + " " ) > Expr.cacheLength ) {
			// Only keep the most recent entries
			delete cache[ keys.shift() ];
		}
		return (cache[ key + " " ] = value);
	}
	return cache;
}

/**
 * Mark a function for special use by Sizzle
 * @param {Function} fn The function to mark
 */
function markFunction( fn ) {
	fn[ expando ] = true;
	return fn;
}

/**
 * Support testing using an element
 * @param {Function} fn Passed the created div and expects a boolean result
 */
function assert( fn ) {
	var div = document.createElement("div");

	try {
		return !!fn( div );
	} catch (e) {
		return false;
	} finally {
		// Remove from its parent by default
		if ( div.parentNode ) {
			div.parentNode.removeChild( div );
		}
		// release memory in IE
		div = null;
	}
}

/**
 * Adds the same handler for all of the specified attrs
 * @param {String} attrs Pipe-separated list of attributes
 * @param {Function} handler The method that will be applied
 */
function addHandle( attrs, handler ) {
	var arr = attrs.split("|"),
		i = attrs.length;

	while ( i-- ) {
		Expr.attrHandle[ arr[i] ] = handler;
	}
}

/**
 * Checks document order of two siblings
 * @param {Element} a
 * @param {Element} b
 * @returns {Number} Returns less than 0 if a precedes b, greater than 0 if a follows b
 */
function siblingCheck( a, b ) {
	var cur = b && a,
		diff = cur && a.nodeType === 1 && b.nodeType === 1 &&
			( ~b.sourceIndex || MAX_NEGATIVE ) -
			( ~a.sourceIndex || MAX_NEGATIVE );

	// Use IE sourceIndex if available on both nodes
	if ( diff ) {
		return diff;
	}

	// Check if b follows a
	if ( cur ) {
		while ( (cur = cur.nextSibling) ) {
			if ( cur === b ) {
				return -1;
			}
		}
	}

	return a ? 1 : -1;
}

/**
 * Returns a function to use in pseudos for input types
 * @param {String} type
 */
function createInputPseudo( type ) {
	return function( elem ) {
		var name = elem.nodeName.toLowerCase();
		return name === "input" && elem.type === type;
	};
}

/**
 * Returns a function to use in pseudos for buttons
 * @param {String} type
 */
function createButtonPseudo( type ) {
	return function( elem ) {
		var name = elem.nodeName.toLowerCase();
		return (name === "input" || name === "button") && elem.type === type;
	};
}

/**
 * Returns a function to use in pseudos for positionals
 * @param {Function} fn
 */
function createPositionalPseudo( fn ) {
	return markFunction(function( argument ) {
		argument = +argument;
		return markFunction(function( seed, matches ) {
			var j,
				matchIndexes = fn( [], seed.length, argument ),
				i = matchIndexes.length;

			// Match elements found at the specified indexes
			while ( i-- ) {
				if ( seed[ (j = matchIndexes[i]) ] ) {
					seed[j] = !(matches[j] = seed[j]);
				}
			}
		});
	});
}

/**
 * Checks a node for validity as a Sizzle context
 * @param {Element|Object=} context
 * @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value
 */
function testContext( context ) {
	return context && typeof context.getElementsByTagName !== strundefined && context;
}

// Expose support vars for convenience
support = Sizzle.support = {};

/**
 * Detects XML nodes
 * @param {Element|Object} elem An element or a document
 * @returns {Boolean} True iff elem is a non-HTML XML node
 */
isXML = Sizzle.isXML = function( elem ) {
	// documentElement is verified for cases where it doesn't yet exist
	// (such as loading iframes in IE - #4833)
	var documentElement = elem && (elem.ownerDocument || elem).documentElement;
	return documentElement ? documentElement.nodeName !== "HTML" : false;
};

/**
 * Sets document-related variables once based on the current document
 * @param {Element|Object} [doc] An element or document object to use to set the document
 * @returns {Object} Returns the current document
 */
setDocument = Sizzle.setDocument = function( node ) {
	var hasCompare,
		doc = node ? node.ownerDocument || node : preferredDoc,
		parent = doc.defaultView;

	// If no document and documentElement is available, return
	if ( doc === document || doc.nodeType !== 9 || !doc.documentElement ) {
		return document;
	}

	// Set our document
	document = doc;
	docElem = doc.documentElement;

	// Support tests
	documentIsHTML = !isXML( doc );

	// Support: IE>8
	// If iframe document is assigned to "document" variable and if iframe has been reloaded,
	// IE will throw "permission denied" error when accessing "document" variable, see jQuery #13936
	// IE6-8 do not support the defaultView property so parent will be undefined
	if ( parent && parent !== parent.top ) {
		// IE11 does not have attachEvent, so all must suffer
		if ( parent.addEventListener ) {
			parent.addEventListener( "unload", function() {
				setDocument();
			}, false );
		} else if ( parent.attachEvent ) {
			parent.attachEvent( "onunload", function() {
				setDocument();
			});
		}
	}

	/* Attributes
	---------------------------------------------------------------------- */

	// Support: IE<8
	// Verify that getAttribute really returns attributes and not properties (excepting IE8 booleans)
	support.attributes = assert(function( div ) {
		div.className = "i";
		return !div.getAttribute("className");
	});

	/* getElement(s)By*
	---------------------------------------------------------------------- */

	// Check if getElementsByTagName("*") returns only elements
	support.getElementsByTagName = assert(function( div ) {
		div.appendChild( doc.createComment("") );
		return !div.getElementsByTagName("*").length;
	});

	// Check if getElementsByClassName can be trusted
	support.getElementsByClassName = rnative.test( doc.getElementsByClassName ) && assert(function( div ) {
		div.innerHTML = "<div class='a'></div><div class='a i'></div>";

		// Support: Safari<4
		// Catch class over-caching
		div.firstChild.className = "i";
		// Support: Opera<10
		// Catch gEBCN failure to find non-leading classes
		return div.getElementsByClassName("i").length === 2;
	});

	// Support: IE<10
	// Check if getElementById returns elements by name
	// The broken getElementById methods don't pick up programatically-set names,
	// so use a roundabout getElementsByName test
	support.getById = assert(function( div ) {
		docElem.appendChild( div ).id = expando;
		return !doc.getElementsByName || !doc.getElementsByName( expando ).length;
	});

	// ID find and filter
	if ( support.getById ) {
		Expr.find["ID"] = function( id, context ) {
			if ( typeof context.getElementById !== strundefined && documentIsHTML ) {
				var m = context.getElementById( id );
				// Check parentNode to catch when Blackberry 4.6 returns
				// nodes that are no longer in the document #6963
				return m && m.parentNode ? [ m ] : [];
			}
		};
		Expr.filter["ID"] = function( id ) {
			var attrId = id.replace( runescape, funescape );
			return function( elem ) {
				return elem.getAttribute("id") === attrId;
			};
		};
	} else {
		// Support: IE6/7
		// getElementById is not reliable as a find shortcut
		delete Expr.find["ID"];

		Expr.filter["ID"] =  function( id ) {
			var attrId = id.replace( runescape, funescape );
			return function( elem ) {
				var node = typeof elem.getAttributeNode !== strundefined && elem.getAttributeNode("id");
				return node && node.value === attrId;
			};
		};
	}

	// Tag
	Expr.find["TAG"] = support.getElementsByTagName ?
		function( tag, context ) {
			if ( typeof context.getElementsByTagName !== strundefined ) {
				return context.getElementsByTagName( tag );
			}
		} :
		function( tag, context ) {
			var elem,
				tmp = [],
				i = 0,
				results = context.getElementsByTagName( tag );

			// Filter out possible comments
			if ( tag === "*" ) {
				while ( (elem = results[i++]) ) {
					if ( elem.nodeType === 1 ) {
						tmp.push( elem );
					}
				}

				return tmp;
			}
			return results;
		};

	// Class
	Expr.find["CLASS"] = support.getElementsByClassName && function( className, context ) {
		if ( typeof context.getElementsByClassName !== strundefined && documentIsHTML ) {
			return context.getElementsByClassName( className );
		}
	};

	/* QSA/matchesSelector
	---------------------------------------------------------------------- */

	// QSA and matchesSelector support

	// matchesSelector(:active) reports false when true (IE9/Opera 11.5)
	rbuggyMatches = [];

	// qSa(:focus) reports false when true (Chrome 21)
	// We allow this because of a bug in IE8/9 that throws an error
	// whenever `document.activeElement` is accessed on an iframe
	// So, we allow :focus to pass through QSA all the time to avoid the IE error
	// See http://bugs.jquery.com/ticket/13378
	rbuggyQSA = [];

	if ( (support.qsa = rnative.test( doc.querySelectorAll )) ) {
		// Build QSA regex
		// Regex strategy adopted from Diego Perini
		assert(function( div ) {
			// Select is set to empty string on purpose
			// This is to test IE's treatment of not explicitly
			// setting a boolean content attribute,
			// since its presence should be enough
			// http://bugs.jquery.com/ticket/12359
			div.innerHTML = "<select msallowclip=''><option selected=''></option></select>";

			// Support: IE8, Opera 11-12.16
			// Nothing should be selected when empty strings follow ^= or $= or *=
			// The test attribute must be unknown in Opera but "safe" for WinRT
			// http://msdn.microsoft.com/en-us/library/ie/hh465388.aspx#attribute_section
			if ( div.querySelectorAll("[msallowclip^='']").length ) {
				rbuggyQSA.push( "[*^$]=" + whitespace + "*(?:''|\"\")" );
			}

			// Support: IE8
			// Boolean attributes and "value" are not treated correctly
			if ( !div.querySelectorAll("[selected]").length ) {
				rbuggyQSA.push( "\\[" + whitespace + "*(?:value|" + booleans + ")" );
			}

			// Webkit/Opera - :checked should return selected option elements
			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
			// IE8 throws error here and will not see later tests
			if ( !div.querySelectorAll(":checked").length ) {
				rbuggyQSA.push(":checked");
			}
		});

		assert(function( div ) {
			// Support: Windows 8 Native Apps
			// The type and name attributes are restricted during .innerHTML assignment
			var input = doc.createElement("input");
			input.setAttribute( "type", "hidden" );
			div.appendChild( input ).setAttribute( "name", "D" );

			// Support: IE8
			// Enforce case-sensitivity of name attribute
			if ( div.querySelectorAll("[name=d]").length ) {
				rbuggyQSA.push( "name" + whitespace + "*[*^$|!~]?=" );
			}

			// FF 3.5 - :enabled/:disabled and hidden elements (hidden elements are still enabled)
			// IE8 throws error here and will not see later tests
			if ( !div.querySelectorAll(":enabled").length ) {
				rbuggyQSA.push( ":enabled", ":disabled" );
			}

			// Opera 10-11 does not throw on post-comma invalid pseudos
			div.querySelectorAll("*,:x");
			rbuggyQSA.push(",.*:");
		});
	}

	if ( (support.matchesSelector = rnative.test( (matches = docElem.matches ||
		docElem.webkitMatchesSelector ||
		docElem.mozMatchesSelector ||
		docElem.oMatchesSelector ||
		docElem.msMatchesSelector) )) ) {

		assert(function( div ) {
			// Check to see if it's possible to do matchesSelector
			// on a disconnected node (IE 9)
			support.disconnectedMatch = matches.call( div, "div" );

			// This should fail with an exception
			// Gecko does not error, returns false instead
			matches.call( div, "[s!='']:x" );
			rbuggyMatches.push( "!=", pseudos );
		});
	}

	rbuggyQSA = rbuggyQSA.length && new RegExp( rbuggyQSA.join("|") );
	rbuggyMatches = rbuggyMatches.length && new RegExp( rbuggyMatches.join("|") );

	/* Contains
	---------------------------------------------------------------------- */
	hasCompare = rnative.test( docElem.compareDocumentPosition );

	// Element contains another
	// Purposefully does not implement inclusive descendent
	// As in, an element does not contain itself
	contains = hasCompare || rnative.test( docElem.contains ) ?
		function( a, b ) {
			var adown = a.nodeType === 9 ? a.documentElement : a,
				bup = b && b.parentNode;
			return a === bup || !!( bup && bup.nodeType === 1 && (
				adown.contains ?
					adown.contains( bup ) :
					a.compareDocumentPosition && a.compareDocumentPosition( bup ) & 16
			));
		} :
		function( a, b ) {
			if ( b ) {
				while ( (b = b.parentNode) ) {
					if ( b === a ) {
						return true;
					}
				}
			}
			return false;
		};

	/* Sorting
	---------------------------------------------------------------------- */

	// Document order sorting
	sortOrder = hasCompare ?
	function( a, b ) {

		// Flag for duplicate removal
		if ( a === b ) {
			hasDuplicate = true;
			return 0;
		}

		// Sort on method existence if only one input has compareDocumentPosition
		var compare = !a.compareDocumentPosition - !b.compareDocumentPosition;
		if ( compare ) {
			return compare;
		}

		// Calculate position if both inputs belong to the same document
		compare = ( a.ownerDocument || a ) === ( b.ownerDocument || b ) ?
			a.compareDocumentPosition( b ) :

			// Otherwise we know they are disconnected
			1;

		// Disconnected nodes
		if ( compare & 1 ||
			(!support.sortDetached && b.compareDocumentPosition( a ) === compare) ) {

			// Choose the first element that is related to our preferred document
			if ( a === doc || a.ownerDocument === preferredDoc && contains(preferredDoc, a) ) {
				return -1;
			}
			if ( b === doc || b.ownerDocument === preferredDoc && contains(preferredDoc, b) ) {
				return 1;
			}

			// Maintain original order
			return sortInput ?
				( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
				0;
		}

		return compare & 4 ? -1 : 1;
	} :
	function( a, b ) {
		// Exit early if the nodes are identical
		if ( a === b ) {
			hasDuplicate = true;
			return 0;
		}

		var cur,
			i = 0,
			aup = a.parentNode,
			bup = b.parentNode,
			ap = [ a ],
			bp = [ b ];

		// Parentless nodes are either documents or disconnected
		if ( !aup || !bup ) {
			return a === doc ? -1 :
				b === doc ? 1 :
				aup ? -1 :
				bup ? 1 :
				sortInput ?
				( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
				0;

		// If the nodes are siblings, we can do a quick check
		} else if ( aup === bup ) {
			return siblingCheck( a, b );
		}

		// Otherwise we need full lists of their ancestors for comparison
		cur = a;
		while ( (cur = cur.parentNode) ) {
			ap.unshift( cur );
		}
		cur = b;
		while ( (cur = cur.parentNode) ) {
			bp.unshift( cur );
		}

		// Walk down the tree looking for a discrepancy
		while ( ap[i] === bp[i] ) {
			i++;
		}

		return i ?
			// Do a sibling check if the nodes have a common ancestor
			siblingCheck( ap[i], bp[i] ) :

			// Otherwise nodes in our document sort first
			ap[i] === preferredDoc ? -1 :
			bp[i] === preferredDoc ? 1 :
			0;
	};

	return doc;
};

Sizzle.matches = function( expr, elements ) {
	return Sizzle( expr, null, null, elements );
};

Sizzle.matchesSelector = function( elem, expr ) {
	// Set document vars if needed
	if ( ( elem.ownerDocument || elem ) !== document ) {
		setDocument( elem );
	}

	// Make sure that attribute selectors are quoted
	expr = expr.replace( rattributeQuotes, "='$1']" );

	if ( support.matchesSelector && documentIsHTML &&
		( !rbuggyMatches || !rbuggyMatches.test( expr ) ) &&
		( !rbuggyQSA     || !rbuggyQSA.test( expr ) ) ) {

		try {
			var ret = matches.call( elem, expr );

			// IE 9's matchesSelector returns false on disconnected nodes
			if ( ret || support.disconnectedMatch ||
					// As well, disconnected nodes are said to be in a document
					// fragment in IE 9
					elem.document && elem.document.nodeType !== 11 ) {
				return ret;
			}
		} catch(e) {}
	}

	return Sizzle( expr, document, null, [ elem ] ).length > 0;
};

Sizzle.contains = function( context, elem ) {
	// Set document vars if needed
	if ( ( context.ownerDocument || context ) !== document ) {
		setDocument( context );
	}
	return contains( context, elem );
};

Sizzle.attr = function( elem, name ) {
	// Set document vars if needed
	if ( ( elem.ownerDocument || elem ) !== document ) {
		setDocument( elem );
	}

	var fn = Expr.attrHandle[ name.toLowerCase() ],
		// Don't get fooled by Object.prototype properties (jQuery #13807)
		val = fn && hasOwn.call( Expr.attrHandle, name.toLowerCase() ) ?
			fn( elem, name, !documentIsHTML ) :
			undefined;

	return val !== undefined ?
		val :
		support.attributes || !documentIsHTML ?
			elem.getAttribute( name ) :
			(val = elem.getAttributeNode(name)) && val.specified ?
				val.value :
				null;
};

Sizzle.error = function( msg ) {
	throw new Error( "Syntax error, unrecognized expression: " + msg );
};

/**
 * Document sorting and removing duplicates
 * @param {ArrayLike} results
 */
Sizzle.uniqueSort = function( results ) {
	var elem,
		duplicates = [],
		j = 0,
		i = 0;

	// Unless we *know* we can detect duplicates, assume their presence
	hasDuplicate = !support.detectDuplicates;
	sortInput = !support.sortStable && results.slice( 0 );
	results.sort( sortOrder );

	if ( hasDuplicate ) {
		while ( (elem = results[i++]) ) {
			if ( elem === results[ i ] ) {
				j = duplicates.push( i );
			}
		}
		while ( j-- ) {
			results.splice( duplicates[ j ], 1 );
		}
	}

	// Clear input after sorting to release objects
	// See https://github.com/jquery/sizzle/pull/225
	sortInput = null;

	return results;
};

/**
 * Utility function for retrieving the text value of an array of DOM nodes
 * @param {Array|Element} elem
 */
getText = Sizzle.getText = function( elem ) {
	var node,
		ret = "",
		i = 0,
		nodeType = elem.nodeType;

	if ( !nodeType ) {
		// If no nodeType, this is expected to be an array
		while ( (node = elem[i++]) ) {
			// Do not traverse comment nodes
			ret += getText( node );
		}
	} else if ( nodeType === 1 || nodeType === 9 || nodeType === 11 ) {
		// Use textContent for elements
		// innerText usage removed for consistency of new lines (jQuery #11153)
		if ( typeof elem.textContent === "string" ) {
			return elem.textContent;
		} else {
			// Traverse its children
			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
				ret += getText( elem );
			}
		}
	} else if ( nodeType === 3 || nodeType === 4 ) {
		return elem.nodeValue;
	}
	// Do not include comment or processing instruction nodes

	return ret;
};

Expr = Sizzle.selectors = {

	// Can be adjusted by the user
	cacheLength: 50,

	createPseudo: markFunction,

	match: matchExpr,

	attrHandle: {},

	find: {},

	relative: {
		">": { dir: "parentNode", first: true },
		" ": { dir: "parentNode" },
		"+": { dir: "previousSibling", first: true },
		"~": { dir: "previousSibling" }
	},

	preFilter: {
		"ATTR": function( match ) {
			match[1] = match[1].replace( runescape, funescape );

			// Move the given value to match[3] whether quoted or unquoted
			match[3] = ( match[3] || match[4] || match[5] || "" ).replace( runescape, funescape );

			if ( match[2] === "~=" ) {
				match[3] = " " + match[3] + " ";
			}

			return match.slice( 0, 4 );
		},

		"CHILD": function( match ) {
			/* matches from matchExpr["CHILD"]
				1 type (only|nth|...)
				2 what (child|of-type)
				3 argument (even|odd|\d*|\d*n([+-]\d+)?|...)
				4 xn-component of xn+y argument ([+-]?\d*n|)
				5 sign of xn-component
				6 x of xn-component
				7 sign of y-component
				8 y of y-component
			*/
			match[1] = match[1].toLowerCase();

			if ( match[1].slice( 0, 3 ) === "nth" ) {
				// nth-* requires argument
				if ( !match[3] ) {
					Sizzle.error( match[0] );
				}

				// numeric x and y parameters for Expr.filter.CHILD
				// remember that false/true cast respectively to 0/1
				match[4] = +( match[4] ? match[5] + (match[6] || 1) : 2 * ( match[3] === "even" || match[3] === "odd" ) );
				match[5] = +( ( match[7] + match[8] ) || match[3] === "odd" );

			// other types prohibit arguments
			} else if ( match[3] ) {
				Sizzle.error( match[0] );
			}

			return match;
		},

		"PSEUDO": function( match ) {
			var excess,
				unquoted = !match[6] && match[2];

			if ( matchExpr["CHILD"].test( match[0] ) ) {
				return null;
			}

			// Accept quoted arguments as-is
			if ( match[3] ) {
				match[2] = match[4] || match[5] || "";

			// Strip excess characters from unquoted arguments
			} else if ( unquoted && rpseudo.test( unquoted ) &&
				// Get excess from tokenize (recursively)
				(excess = tokenize( unquoted, true )) &&
				// advance to the next closing parenthesis
				(excess = unquoted.indexOf( ")", unquoted.length - excess ) - unquoted.length) ) {

				// excess is a negative index
				match[0] = match[0].slice( 0, excess );
				match[2] = unquoted.slice( 0, excess );
			}

			// Return only captures needed by the pseudo filter method (type and argument)
			return match.slice( 0, 3 );
		}
	},

	filter: {

		"TAG": function( nodeNameSelector ) {
			var nodeName = nodeNameSelector.replace( runescape, funescape ).toLowerCase();
			return nodeNameSelector === "*" ?
				function() { return true; } :
				function( elem ) {
					return elem.nodeName && elem.nodeName.toLowerCase() === nodeName;
				};
		},

		"CLASS": function( className ) {
			var pattern = classCache[ className + " " ];

			return pattern ||
				(pattern = new RegExp( "(^|" + whitespace + ")" + className + "(" + whitespace + "|$)" )) &&
				classCache( className, function( elem ) {
					return pattern.test( typeof elem.className === "string" && elem.className || typeof elem.getAttribute !== strundefined && elem.getAttribute("class") || "" );
				});
		},

		"ATTR": function( name, operator, check ) {
			return function( elem ) {
				var result = Sizzle.attr( elem, name );

				if ( result == null ) {
					return operator === "!=";
				}
				if ( !operator ) {
					return true;
				}

				result += "";

				return operator === "=" ? result === check :
					operator === "!=" ? result !== check :
					operator === "^=" ? check && result.indexOf( check ) === 0 :
					operator === "*=" ? check && result.indexOf( check ) > -1 :
					operator === "$=" ? check && result.slice( -check.length ) === check :
					operator === "~=" ? ( " " + result + " " ).indexOf( check ) > -1 :
					operator === "|=" ? result === check || result.slice( 0, check.length + 1 ) === check + "-" :
					false;
			};
		},

		"CHILD": function( type, what, argument, first, last ) {
			var simple = type.slice( 0, 3 ) !== "nth",
				forward = type.slice( -4 ) !== "last",
				ofType = what === "of-type";

			return first === 1 && last === 0 ?

				// Shortcut for :nth-*(n)
				function( elem ) {
					return !!elem.parentNode;
				} :

				function( elem, context, xml ) {
					var cache, outerCache, node, diff, nodeIndex, start,
						dir = simple !== forward ? "nextSibling" : "previousSibling",
						parent = elem.parentNode,
						name = ofType && elem.nodeName.toLowerCase(),
						useCache = !xml && !ofType;

					if ( parent ) {

						// :(first|last|only)-(child|of-type)
						if ( simple ) {
							while ( dir ) {
								node = elem;
								while ( (node = node[ dir ]) ) {
									if ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) {
										return false;
									}
								}
								// Reverse direction for :only-* (if we haven't yet done so)
								start = dir = type === "only" && !start && "nextSibling";
							}
							return true;
						}

						start = [ forward ? parent.firstChild : parent.lastChild ];

						// non-xml :nth-child(...) stores cache data on `parent`
						if ( forward && useCache ) {
							// Seek `elem` from a previously-cached index
							outerCache = parent[ expando ] || (parent[ expando ] = {});
							cache = outerCache[ type ] || [];
							nodeIndex = cache[0] === dirruns && cache[1];
							diff = cache[0] === dirruns && cache[2];
							node = nodeIndex && parent.childNodes[ nodeIndex ];

							while ( (node = ++nodeIndex && node && node[ dir ] ||

								// Fallback to seeking `elem` from the start
								(diff = nodeIndex = 0) || start.pop()) ) {

								// When found, cache indexes on `parent` and break
								if ( node.nodeType === 1 && ++diff && node === elem ) {
									outerCache[ type ] = [ dirruns, nodeIndex, diff ];
									break;
								}
							}

						// Use previously-cached element index if available
						} else if ( useCache && (cache = (elem[ expando ] || (elem[ expando ] = {}))[ type ]) && cache[0] === dirruns ) {
							diff = cache[1];

						// xml :nth-child(...) or :nth-last-child(...) or :nth(-last)?-of-type(...)
						} else {
							// Use the same loop as above to seek `elem` from the start
							while ( (node = ++nodeIndex && node && node[ dir ] ||
								(diff = nodeIndex = 0) || start.pop()) ) {

								if ( ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) && ++diff ) {
									// Cache the index of each encountered element
									if ( useCache ) {
										(node[ expando ] || (node[ expando ] = {}))[ type ] = [ dirruns, diff ];
									}

									if ( node === elem ) {
										break;
									}
								}
							}
						}

						// Incorporate the offset, then check against cycle size
						diff -= last;
						return diff === first || ( diff % first === 0 && diff / first >= 0 );
					}
				};
		},

		"PSEUDO": function( pseudo, argument ) {
			// pseudo-class names are case-insensitive
			// http://www.w3.org/TR/selectors/#pseudo-classes
			// Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
			// Remember that setFilters inherits from pseudos
			var args,
				fn = Expr.pseudos[ pseudo ] || Expr.setFilters[ pseudo.toLowerCase() ] ||
					Sizzle.error( "unsupported pseudo: " + pseudo );

			// The user may use createPseudo to indicate that
			// arguments are needed to create the filter function
			// just as Sizzle does
			if ( fn[ expando ] ) {
				return fn( argument );
			}

			// But maintain support for old signatures
			if ( fn.length > 1 ) {
				args = [ pseudo, pseudo, "", argument ];
				return Expr.setFilters.hasOwnProperty( pseudo.toLowerCase() ) ?
					markFunction(function( seed, matches ) {
						var idx,
							matched = fn( seed, argument ),
							i = matched.length;
						while ( i-- ) {
							idx = indexOf.call( seed, matched[i] );
							seed[ idx ] = !( matches[ idx ] = matched[i] );
						}
					}) :
					function( elem ) {
						return fn( elem, 0, args );
					};
			}

			return fn;
		}
	},

	pseudos: {
		// Potentially complex pseudos
		"not": markFunction(function( selector ) {
			// Trim the selector passed to compile
			// to avoid treating leading and trailing
			// spaces as combinators
			var input = [],
				results = [],
				matcher = compile( selector.replace( rtrim, "$1" ) );

			return matcher[ expando ] ?
				markFunction(function( seed, matches, context, xml ) {
					var elem,
						unmatched = matcher( seed, null, xml, [] ),
						i = seed.length;

					// Match elements unmatched by `matcher`
					while ( i-- ) {
						if ( (elem = unmatched[i]) ) {
							seed[i] = !(matches[i] = elem);
						}
					}
				}) :
				function( elem, context, xml ) {
					input[0] = elem;
					matcher( input, null, xml, results );
					return !results.pop();
				};
		}),

		"has": markFunction(function( selector ) {
			return function( elem ) {
				return Sizzle( selector, elem ).length > 0;
			};
		}),

		"contains": markFunction(function( text ) {
			return function( elem ) {
				return ( elem.textContent || elem.innerText || getText( elem ) ).indexOf( text ) > -1;
			};
		}),

		// "Whether an element is represented by a :lang() selector
		// is based solely on the element's language value
		// being equal to the identifier C,
		// or beginning with the identifier C immediately followed by "-".
		// The matching of C against the element's language value is performed case-insensitively.
		// The identifier C does not have to be a valid language name."
		// http://www.w3.org/TR/selectors/#lang-pseudo
		"lang": markFunction( function( lang ) {
			// lang value must be a valid identifier
			if ( !ridentifier.test(lang || "") ) {
				Sizzle.error( "unsupported lang: " + lang );
			}
			lang = lang.replace( runescape, funescape ).toLowerCase();
			return function( elem ) {
				var elemLang;
				do {
					if ( (elemLang = documentIsHTML ?
						elem.lang :
						elem.getAttribute("xml:lang") || elem.getAttribute("lang")) ) {

						elemLang = elemLang.toLowerCase();
						return elemLang === lang || elemLang.indexOf( lang + "-" ) === 0;
					}
				} while ( (elem = elem.parentNode) && elem.nodeType === 1 );
				return false;
			};
		}),

		// Miscellaneous
		"target": function( elem ) {
			var hash = window.location && window.location.hash;
			return hash && hash.slice( 1 ) === elem.id;
		},

		"root": function( elem ) {
			return elem === docElem;
		},

		"focus": function( elem ) {
			return elem === document.activeElement && (!document.hasFocus || document.hasFocus()) && !!(elem.type || elem.href || ~elem.tabIndex);
		},

		// Boolean properties
		"enabled": function( elem ) {
			return elem.disabled === false;
		},

		"disabled": function( elem ) {
			return elem.disabled === true;
		},

		"checked": function( elem ) {
			// In CSS3, :checked should return both checked and selected elements
			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
			var nodeName = elem.nodeName.toLowerCase();
			return (nodeName === "input" && !!elem.checked) || (nodeName === "option" && !!elem.selected);
		},

		"selected": function( elem ) {
			// Accessing this property makes selected-by-default
			// options in Safari work properly
			if ( elem.parentNode ) {
				elem.parentNode.selectedIndex;
			}

			return elem.selected === true;
		},

		// Contents
		"empty": function( elem ) {
			// http://www.w3.org/TR/selectors/#empty-pseudo
			// :empty is negated by element (1) or content nodes (text: 3; cdata: 4; entity ref: 5),
			//   but not by others (comment: 8; processing instruction: 7; etc.)
			// nodeType < 6 works because attributes (2) do not appear as children
			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
				if ( elem.nodeType < 6 ) {
					return false;
				}
			}
			return true;
		},

		"parent": function( elem ) {
			return !Expr.pseudos["empty"]( elem );
		},

		// Element/input types
		"header": function( elem ) {
			return rheader.test( elem.nodeName );
		},

		"input": function( elem ) {
			return rinputs.test( elem.nodeName );
		},

		"button": function( elem ) {
			var name = elem.nodeName.toLowerCase();
			return name === "input" && elem.type === "button" || name === "button";
		},

		"text": function( elem ) {
			var attr;
			return elem.nodeName.toLowerCase() === "input" &&
				elem.type === "text" &&

				// Support: IE<8
				// New HTML5 attribute values (e.g., "search") appear with elem.type === "text"
				( (attr = elem.getAttribute("type")) == null || attr.toLowerCase() === "text" );
		},

		// Position-in-collection
		"first": createPositionalPseudo(function() {
			return [ 0 ];
		}),

		"last": createPositionalPseudo(function( matchIndexes, length ) {
			return [ length - 1 ];
		}),

		"eq": createPositionalPseudo(function( matchIndexes, length, argument ) {
			return [ argument < 0 ? argument + length : argument ];
		}),

		"even": createPositionalPseudo(function( matchIndexes, length ) {
			var i = 0;
			for ( ; i < length; i += 2 ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		}),

		"odd": createPositionalPseudo(function( matchIndexes, length ) {
			var i = 1;
			for ( ; i < length; i += 2 ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		}),

		"lt": createPositionalPseudo(function( matchIndexes, length, argument ) {
			var i = argument < 0 ? argument + length : argument;
			for ( ; --i >= 0; ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		}),

		"gt": createPositionalPseudo(function( matchIndexes, length, argument ) {
			var i = argument < 0 ? argument + length : argument;
			for ( ; ++i < length; ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		})
	}
};

Expr.pseudos["nth"] = Expr.pseudos["eq"];

// Add button/input type pseudos
for ( i in { radio: true, checkbox: true, file: true, password: true, image: true } ) {
	Expr.pseudos[ i ] = createInputPseudo( i );
}
for ( i in { submit: true, reset: true } ) {
	Expr.pseudos[ i ] = createButtonPseudo( i );
}

// Easy API for creating new setFilters
function setFilters() {}
setFilters.prototype = Expr.filters = Expr.pseudos;
Expr.setFilters = new setFilters();

tokenize = Sizzle.tokenize = function( selector, parseOnly ) {
	var matched, match, tokens, type,
		soFar, groups, preFilters,
		cached = tokenCache[ selector + " " ];

	if ( cached ) {
		return parseOnly ? 0 : cached.slice( 0 );
	}

	soFar = selector;
	groups = [];
	preFilters = Expr.preFilter;

	while ( soFar ) {

		// Comma and first run
		if ( !matched || (match = rcomma.exec( soFar )) ) {
			if ( match ) {
				// Don't consume trailing commas as valid
				soFar = soFar.slice( match[0].length ) || soFar;
			}
			groups.push( (tokens = []) );
		}

		matched = false;

		// Combinators
		if ( (match = rcombinators.exec( soFar )) ) {
			matched = match.shift();
			tokens.push({
				value: matched,
				// Cast descendant combinators to space
				type: match[0].replace( rtrim, " " )
			});
			soFar = soFar.slice( matched.length );
		}

		// Filters
		for ( type in Expr.filter ) {
			if ( (match = matchExpr[ type ].exec( soFar )) && (!preFilters[ type ] ||
				(match = preFilters[ type ]( match ))) ) {
				matched = match.shift();
				tokens.push({
					value: matched,
					type: type,
					matches: match
				});
				soFar = soFar.slice( matched.length );
			}
		}

		if ( !matched ) {
			break;
		}
	}

	// Return the length of the invalid excess
	// if we're just parsing
	// Otherwise, throw an error or return tokens
	return parseOnly ?
		soFar.length :
		soFar ?
			Sizzle.error( selector ) :
			// Cache the tokens
			tokenCache( selector, groups ).slice( 0 );
};

function toSelector( tokens ) {
	var i = 0,
		len = tokens.length,
		selector = "";
	for ( ; i < len; i++ ) {
		selector += tokens[i].value;
	}
	return selector;
}

function addCombinator( matcher, combinator, base ) {
	var dir = combinator.dir,
		checkNonElements = base && dir === "parentNode",
		doneName = done++;

	return combinator.first ?
		// Check against closest ancestor/preceding element
		function( elem, context, xml ) {
			while ( (elem = elem[ dir ]) ) {
				if ( elem.nodeType === 1 || checkNonElements ) {
					return matcher( elem, context, xml );
				}
			}
		} :

		// Check against all ancestor/preceding elements
		function( elem, context, xml ) {
			var oldCache, outerCache,
				newCache = [ dirruns, doneName ];

			// We can't set arbitrary data on XML nodes, so they don't benefit from dir caching
			if ( xml ) {
				while ( (elem = elem[ dir ]) ) {
					if ( elem.nodeType === 1 || checkNonElements ) {
						if ( matcher( elem, context, xml ) ) {
							return true;
						}
					}
				}
			} else {
				while ( (elem = elem[ dir ]) ) {
					if ( elem.nodeType === 1 || checkNonElements ) {
						outerCache = elem[ expando ] || (elem[ expando ] = {});
						if ( (oldCache = outerCache[ dir ]) &&
							oldCache[ 0 ] === dirruns && oldCache[ 1 ] === doneName ) {

							// Assign to newCache so results back-propagate to previous elements
							return (newCache[ 2 ] = oldCache[ 2 ]);
						} else {
							// Reuse newcache so results back-propagate to previous elements
							outerCache[ dir ] = newCache;

							// A match means we're done; a fail means we have to keep checking
							if ( (newCache[ 2 ] = matcher( elem, context, xml )) ) {
								return true;
							}
						}
					}
				}
			}
		};
}

function elementMatcher( matchers ) {
	return matchers.length > 1 ?
		function( elem, context, xml ) {
			var i = matchers.length;
			while ( i-- ) {
				if ( !matchers[i]( elem, context, xml ) ) {
					return false;
				}
			}
			return true;
		} :
		matchers[0];
}

function multipleContexts( selector, contexts, results ) {
	var i = 0,
		len = contexts.length;
	for ( ; i < len; i++ ) {
		Sizzle( selector, contexts[i], results );
	}
	return results;
}

function condense( unmatched, map, filter, context, xml ) {
	var elem,
		newUnmatched = [],
		i = 0,
		len = unmatched.length,
		mapped = map != null;

	for ( ; i < len; i++ ) {
		if ( (elem = unmatched[i]) ) {
			if ( !filter || filter( elem, context, xml ) ) {
				newUnmatched.push( elem );
				if ( mapped ) {
					map.push( i );
				}
			}
		}
	}

	return newUnmatched;
}

function setMatcher( preFilter, selector, matcher, postFilter, postFinder, postSelector ) {
	if ( postFilter && !postFilter[ expando ] ) {
		postFilter = setMatcher( postFilter );
	}
	if ( postFinder && !postFinder[ expando ] ) {
		postFinder = setMatcher( postFinder, postSelector );
	}
	return markFunction(function( seed, results, context, xml ) {
		var temp, i, elem,
			preMap = [],
			postMap = [],
			preexisting = results.length,

			// Get initial elements from seed or context
			elems = seed || multipleContexts( selector || "*", context.nodeType ? [ context ] : context, [] ),

			// Prefilter to get matcher input, preserving a map for seed-results synchronization
			matcherIn = preFilter && ( seed || !selector ) ?
				condense( elems, preMap, preFilter, context, xml ) :
				elems,

			matcherOut = matcher ?
				// If we have a postFinder, or filtered seed, or non-seed postFilter or preexisting results,
				postFinder || ( seed ? preFilter : preexisting || postFilter ) ?

					// ...intermediate processing is necessary
					[] :

					// ...otherwise use results directly
					results :
				matcherIn;

		// Find primary matches
		if ( matcher ) {
			matcher( matcherIn, matcherOut, context, xml );
		}

		// Apply postFilter
		if ( postFilter ) {
			temp = condense( matcherOut, postMap );
			postFilter( temp, [], context, xml );

			// Un-match failing elements by moving them back to matcherIn
			i = temp.length;
			while ( i-- ) {
				if ( (elem = temp[i]) ) {
					matcherOut[ postMap[i] ] = !(matcherIn[ postMap[i] ] = elem);
				}
			}
		}

		if ( seed ) {
			if ( postFinder || preFilter ) {
				if ( postFinder ) {
					// Get the final matcherOut by condensing this intermediate into postFinder contexts
					temp = [];
					i = matcherOut.length;
					while ( i-- ) {
						if ( (elem = matcherOut[i]) ) {
							// Restore matcherIn since elem is not yet a final match
							temp.push( (matcherIn[i] = elem) );
						}
					}
					postFinder( null, (matcherOut = []), temp, xml );
				}

				// Move matched elements from seed to results to keep them synchronized
				i = matcherOut.length;
				while ( i-- ) {
					if ( (elem = matcherOut[i]) &&
						(temp = postFinder ? indexOf.call( seed, elem ) : preMap[i]) > -1 ) {

						seed[temp] = !(results[temp] = elem);
					}
				}
			}

		// Add elements to results, through postFinder if defined
		} else {
			matcherOut = condense(
				matcherOut === results ?
					matcherOut.splice( preexisting, matcherOut.length ) :
					matcherOut
			);
			if ( postFinder ) {
				postFinder( null, results, matcherOut, xml );
			} else {
				push.apply( results, matcherOut );
			}
		}
	});
}

function matcherFromTokens( tokens ) {
	var checkContext, matcher, j,
		len = tokens.length,
		leadingRelative = Expr.relative[ tokens[0].type ],
		implicitRelative = leadingRelative || Expr.relative[" "],
		i = leadingRelative ? 1 : 0,

		// The foundational matcher ensures that elements are reachable from top-level context(s)
		matchContext = addCombinator( function( elem ) {
			return elem === checkContext;
		}, implicitRelative, true ),
		matchAnyContext = addCombinator( function( elem ) {
			return indexOf.call( checkContext, elem ) > -1;
		}, implicitRelative, true ),
		matchers = [ function( elem, context, xml ) {
			return ( !leadingRelative && ( xml || context !== outermostContext ) ) || (
				(checkContext = context).nodeType ?
					matchContext( elem, context, xml ) :
					matchAnyContext( elem, context, xml ) );
		} ];

	for ( ; i < len; i++ ) {
		if ( (matcher = Expr.relative[ tokens[i].type ]) ) {
			matchers = [ addCombinator(elementMatcher( matchers ), matcher) ];
		} else {
			matcher = Expr.filter[ tokens[i].type ].apply( null, tokens[i].matches );

			// Return special upon seeing a positional matcher
			if ( matcher[ expando ] ) {
				// Find the next relative operator (if any) for proper handling
				j = ++i;
				for ( ; j < len; j++ ) {
					if ( Expr.relative[ tokens[j].type ] ) {
						break;
					}
				}
				return setMatcher(
					i > 1 && elementMatcher( matchers ),
					i > 1 && toSelector(
						// If the preceding token was a descendant combinator, insert an implicit any-element `*`
						tokens.slice( 0, i - 1 ).concat({ value: tokens[ i - 2 ].type === " " ? "*" : "" })
					).replace( rtrim, "$1" ),
					matcher,
					i < j && matcherFromTokens( tokens.slice( i, j ) ),
					j < len && matcherFromTokens( (tokens = tokens.slice( j )) ),
					j < len && toSelector( tokens )
				);
			}
			matchers.push( matcher );
		}
	}

	return elementMatcher( matchers );
}

function matcherFromGroupMatchers( elementMatchers, setMatchers ) {
	var bySet = setMatchers.length > 0,
		byElement = elementMatchers.length > 0,
		superMatcher = function( seed, context, xml, results, outermost ) {
			var elem, j, matcher,
				matchedCount = 0,
				i = "0",
				unmatched = seed && [],
				setMatched = [],
				contextBackup = outermostContext,
				// We must always have either seed elements or outermost context
				elems = seed || byElement && Expr.find["TAG"]( "*", outermost ),
				// Use integer dirruns iff this is the outermost matcher
				dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1),
				len = elems.length;

			if ( outermost ) {
				outermostContext = context !== document && context;
			}

			// Add elements passing elementMatchers directly to results
			// Keep `i` a string if there are no elements so `matchedCount` will be "00" below
			// Support: IE<9, Safari
			// Tolerate NodeList properties (IE: "length"; Safari: <number>) matching elements by id
			for ( ; i !== len && (elem = elems[i]) != null; i++ ) {
				if ( byElement && elem ) {
					j = 0;
					while ( (matcher = elementMatchers[j++]) ) {
						if ( matcher( elem, context, xml ) ) {
							results.push( elem );
							break;
						}
					}
					if ( outermost ) {
						dirruns = dirrunsUnique;
					}
				}

				// Track unmatched elements for set filters
				if ( bySet ) {
					// They will have gone through all possible matchers
					if ( (elem = !matcher && elem) ) {
						matchedCount--;
					}

					// Lengthen the array for every element, matched or not
					if ( seed ) {
						unmatched.push( elem );
					}
				}
			}

			// Apply set filters to unmatched elements
			matchedCount += i;
			if ( bySet && i !== matchedCount ) {
				j = 0;
				while ( (matcher = setMatchers[j++]) ) {
					matcher( unmatched, setMatched, context, xml );
				}

				if ( seed ) {
					// Reintegrate element matches to eliminate the need for sorting
					if ( matchedCount > 0 ) {
						while ( i-- ) {
							if ( !(unmatched[i] || setMatched[i]) ) {
								setMatched[i] = pop.call( results );
							}
						}
					}

					// Discard index placeholder values to get only actual matches
					setMatched = condense( setMatched );
				}

				// Add matches to results
				push.apply( results, setMatched );

				// Seedless set matches succeeding multiple successful matchers stipulate sorting
				if ( outermost && !seed && setMatched.length > 0 &&
					( matchedCount + setMatchers.length ) > 1 ) {

					Sizzle.uniqueSort( results );
				}
			}

			// Override manipulation of globals by nested matchers
			if ( outermost ) {
				dirruns = dirrunsUnique;
				outermostContext = contextBackup;
			}

			return unmatched;
		};

	return bySet ?
		markFunction( superMatcher ) :
		superMatcher;
}

compile = Sizzle.compile = function( selector, match /* Internal Use Only */ ) {
	var i,
		setMatchers = [],
		elementMatchers = [],
		cached = compilerCache[ selector + " " ];

	if ( !cached ) {
		// Generate a function of recursive functions that can be used to check each element
		if ( !match ) {
			match = tokenize( selector );
		}
		i = match.length;
		while ( i-- ) {
			cached = matcherFromTokens( match[i] );
			if ( cached[ expando ] ) {
				setMatchers.push( cached );
			} else {
				elementMatchers.push( cached );
			}
		}

		// Cache the compiled function
		cached = compilerCache( selector, matcherFromGroupMatchers( elementMatchers, setMatchers ) );

		// Save selector and tokenization
		cached.selector = selector;
	}
	return cached;
};

/**
 * A low-level selection function that works with Sizzle's compiled
 *  selector functions
 * @param {String|Function} selector A selector or a pre-compiled
 *  selector function built with Sizzle.compile
 * @param {Element} context
 * @param {Array} [results]
 * @param {Array} [seed] A set of elements to match against
 */
select = Sizzle.select = function( selector, context, results, seed ) {
	var i, tokens, token, type, find,
		compiled = typeof selector === "function" && selector,
		match = !seed && tokenize( (selector = compiled.selector || selector) );

	results = results || [];

	// Try to minimize operations if there is no seed and only one group
	if ( match.length === 1 ) {

		// Take a shortcut and set the context if the root selector is an ID
		tokens = match[0] = match[0].slice( 0 );
		if ( tokens.length > 2 && (token = tokens[0]).type === "ID" &&
				support.getById && context.nodeType === 9 && documentIsHTML &&
				Expr.relative[ tokens[1].type ] ) {

			context = ( Expr.find["ID"]( token.matches[0].replace(runescape, funescape), context ) || [] )[0];
			if ( !context ) {
				return results;

			// Precompiled matchers will still verify ancestry, so step up a level
			} else if ( compiled ) {
				context = context.parentNode;
			}

			selector = selector.slice( tokens.shift().value.length );
		}

		// Fetch a seed set for right-to-left matching
		i = matchExpr["needsContext"].test( selector ) ? 0 : tokens.length;
		while ( i-- ) {
			token = tokens[i];

			// Abort if we hit a combinator
			if ( Expr.relative[ (type = token.type) ] ) {
				break;
			}
			if ( (find = Expr.find[ type ]) ) {
				// Search, expanding context for leading sibling combinators
				if ( (seed = find(
					token.matches[0].replace( runescape, funescape ),
					rsibling.test( tokens[0].type ) && testContext( context.parentNode ) || context
				)) ) {

					// If seed is empty or no tokens remain, we can return early
					tokens.splice( i, 1 );
					selector = seed.length && toSelector( tokens );
					if ( !selector ) {
						push.apply( results, seed );
						return results;
					}

					break;
				}
			}
		}
	}

	// Compile and execute a filtering function if one is not provided
	// Provide `match` to avoid retokenization if we modified the selector above
	( compiled || compile( selector, match ) )(
		seed,
		context,
		!documentIsHTML,
		results,
		rsibling.test( selector ) && testContext( context.parentNode ) || context
	);
	return results;
};

// One-time assignments

// Sort stability
support.sortStable = expando.split("").sort( sortOrder ).join("") === expando;

// Support: Chrome<14
// Always assume duplicates if they aren't passed to the comparison function
support.detectDuplicates = !!hasDuplicate;

// Initialize against the default document
setDocument();

// Support: Webkit<537.32 - Safari 6.0.3/Chrome 25 (fixed in Chrome 27)
// Detached nodes confoundingly follow *each other*
support.sortDetached = assert(function( div1 ) {
	// Should return 1, but returns 4 (following)
	return div1.compareDocumentPosition( document.createElement("div") ) & 1;
});

// Support: IE<8
// Prevent attribute/property "interpolation"
// http://msdn.microsoft.com/en-us/library/ms536429%28VS.85%29.aspx
if ( !assert(function( div ) {
	div.innerHTML = "<a href='#'></a>";
	return div.firstChild.getAttribute("href") === "#" ;
}) ) {
	addHandle( "type|href|height|width", function( elem, name, isXML ) {
		if ( !isXML ) {
			return elem.getAttribute( name, name.toLowerCase() === "type" ? 1 : 2 );
		}
	});
}

// Support: IE<9
// Use defaultValue in place of getAttribute("value")
if ( !support.attributes || !assert(function( div ) {
	div.innerHTML = "<input/>";
	div.firstChild.setAttribute( "value", "" );
	return div.firstChild.getAttribute( "value" ) === "";
}) ) {
	addHandle( "value", function( elem, name, isXML ) {
		if ( !isXML && elem.nodeName.toLowerCase() === "input" ) {
			return elem.defaultValue;
		}
	});
}

// Support: IE<9
// Use getAttributeNode to fetch booleans when getAttribute lies
if ( !assert(function( div ) {
	return div.getAttribute("disabled") == null;
}) ) {
	addHandle( booleans, function( elem, name, isXML ) {
		var val;
		if ( !isXML ) {
			return elem[ name ] === true ? name.toLowerCase() :
					(val = elem.getAttributeNode( name )) && val.specified ?
					val.value :
				null;
		}
	});
}

// EXPOSE
if ( typeof define === "function" && define.amd ) {
	define(function() { return Sizzle; });
// Sizzle requires that there be a global window in Common-JS like environments
} else if ( typeof module !== "undefined" && module.exports ) {
	module.exports = Sizzle;
} else {
	window.Sizzle = Sizzle;
}
// EXPOSE

})( window );

/*! 
 * LESS - Leaner CSS v1.6.0 
 * http://lesscss.org 
 * 
 * Copyright (c) 2009-2014, Alexis Sellier <self@cloudhead.net> 
 * Licensed under the Apache v2 License. 
 * 
 */ 

 /** * @license Apache v2
 */ 



(function (window, undefined) {//
// Stub out `require` in the browser
//
function require(arg) {
    return window.less[arg.split('/')[1]];
};


if (typeof(window.less) === 'undefined' || typeof(window.less.nodeType) !== 'undefined') { window.less = {}; }
less = window.less;
tree = window.less.tree = {};
less.mode = 'browser';

var less, tree;

// Node.js does not have a header file added which defines less
if (less === undefined) {
    less = exports;
    tree = require('./tree');
    less.mode = 'node';
}
//
// less.js - parser
//
//    A relatively straight-forward predictive parser.
//    There is no tokenization/lexing stage, the input is parsed
//    in one sweep.
//
//    To make the parser fast enough to run in the browser, several
//    optimization had to be made:
//
//    - Matching and slicing on a huge input is often cause of slowdowns.
//      The solution is to chunkify the input into smaller strings.
//      The chunks are stored in the `chunks` var,
//      `j` holds the current chunk index, and `currentPos` holds
//      the index of the current chunk in relation to `input`.
//      This gives us an almost 4x speed-up.
//
//    - In many cases, we don't need to match individual tokens;
//      for example, if a value doesn't hold any variables, operations
//      or dynamic references, the parser can effectively 'skip' it,
//      treating it as a literal.
//      An example would be '1px solid #000' - which evaluates to itself,
//      we don't need to know what the individual components are.
//      The drawback, of course is that you don't get the benefits of
//      syntax-checking on the CSS. This gives us a 50% speed-up in the parser,
//      and a smaller speed-up in the code-gen.
//
//
//    Token matching is done with the `$` function, which either takes
//    a terminal string or regexp, or a non-terminal function to call.
//    It also takes care of moving all the indices forwards.
//
//
less.Parser = function Parser(env) {
    var input,       // LeSS input string
        i,           // current index in `input`
        j,           // current chunk
        temp,        // temporarily holds a chunk's state, for backtracking
        memo,        // temporarily holds `i`, when backtracking
        furthest,    // furthest index the parser has gone to
        chunks,      // chunkified input
        current,     // current chunk
        currentPos,  // index of current chunk, in `input`
        parser,
        parsers,
        rootFilename = env && env.filename;

    // Top parser on an import tree must be sure there is one "env"
    // which will then be passed around by reference.
    if (!(env instanceof tree.parseEnv)) {
        env = new tree.parseEnv(env);
    }

    var imports = this.imports = {
        paths: env.paths || [],  // Search paths, when importing
        queue: [],               // Files which haven't been imported yet
        files: env.files,        // Holds the imported parse trees
        contents: env.contents,  // Holds the imported file contents
        contentsIgnoredChars: env.contentsIgnoredChars, // lines inserted, not in the original less
        mime:  env.mime,         // MIME type of .less files
        error: null,             // Error in parsing/evaluating an import
        push: function (path, currentFileInfo, importOptions, callback) {
            var parserImports = this;
            this.queue.push(path);

            var fileParsedFunc = function (e, root, fullPath) {
                parserImports.queue.splice(parserImports.queue.indexOf(path), 1); // Remove the path from the queue

                var importedPreviously = fullPath in parserImports.files || fullPath === rootFilename;

                parserImports.files[fullPath] = root;                        // Store the root

                if (e && !parserImports.error) { parserImports.error = e; }

                callback(e, root, importedPreviously, fullPath);
            };

            if (less.Parser.importer) {
                less.Parser.importer(path, currentFileInfo, fileParsedFunc, env);
            } else {
                less.Parser.fileLoader(path, currentFileInfo, function(e, contents, fullPath, newFileInfo) {
                    if (e) {fileParsedFunc(e); return;}

                    var newEnv = new tree.parseEnv(env);

                    newEnv.currentFileInfo = newFileInfo;
                    newEnv.processImports = false;
                    newEnv.contents[fullPath] = contents;

                    if (currentFileInfo.reference || importOptions.reference) {
                        newFileInfo.reference = true;
                    }

                    if (importOptions.inline) {
                        fileParsedFunc(null, contents, fullPath);
                    } else {
                        new(less.Parser)(newEnv).parse(contents, function (e, root) {
                            fileParsedFunc(e, root, fullPath);
                        });
                    }
                }, env);
            }
        }
    };

    function save()    { temp = current; memo = currentPos = i; }
    function restore() { current = temp; currentPos = i = memo; }

    function sync() {
        if (i > currentPos) {
            current = current.slice(i - currentPos);
            currentPos = i;
        }
    }
    function isWhitespace(str, pos) {
        var code = str.charCodeAt(pos | 0);
        return (code <= 32) && (code === 32 || code === 10 || code === 9);
    }
    //
    // Parse from a token, regexp or string, and move forward if match
    //
    function $(tok) {
        var tokType = typeof tok,
            match, length;

        // Either match a single character in the input,
        // or match a regexp in the current chunk (`current`).
        //
        if (tokType === "string") {
            if (input.charAt(i) !== tok) {
                return null;
            }
            skipWhitespace(1);
            return tok;
        }

        // regexp
        sync ();
        if (! (match = tok.exec(current))) {
            return null;
        }

        length = match[0].length;

        // The match is confirmed, add the match length to `i`,
        // and consume any extra white-space characters (' ' || '\n')
        // which come after that. The reason for this is that LeSS's
        // grammar is mostly white-space insensitive.
        //
        skipWhitespace(length);

        if(typeof(match) === 'string') {
            return match;
        } else {
            return match.length === 1 ? match[0] : match;
        }
    }

    // Specialization of $(tok)
    function $re(tok) {
        if (i > currentPos) {
            current = current.slice(i - currentPos);
            currentPos = i;
        }
        var m = tok.exec(current);
        if (!m) {
            return null;
        }

        skipWhitespace(m[0].length);
        if(typeof m === "string") {
            return m;
        }

        return m.length === 1 ? m[0] : m;
    }

    var _$re = $re;

    // Specialization of $(tok)
    function $char(tok) {
        if (input.charAt(i) !== tok) {
            return null;
        }
        skipWhitespace(1);
        return tok;
    }

    function skipWhitespace(length) {
        var oldi = i, oldj = j,
            curr = i - currentPos,
            endIndex = i + current.length - curr,
            mem = (i += length),
            inp = input,
            c;

        for (; i < endIndex; i++) {
            c = inp.charCodeAt(i);
            if (c > 32) {
                break;
            }

            if ((c !== 32) && (c !== 10) && (c !== 9) && (c !== 13)) {
                break;
            }
         }

        current = current.slice(length + i - mem + curr);
        currentPos = i;

        if (!current.length && (j < chunks.length - 1)) {
            current = chunks[++j];
        }

        return oldi !== i || oldj !== j;
    }

    function expect(arg, msg) {
        var result = (typeof arg === "function") ? arg.call(parsers) : $(arg);
        if (result) {
            return result;
        }
        error(msg || (typeof(arg) === 'string' ? "expected '" + arg + "' got '" + input.charAt(i) + "'"
                                               : "unexpected token"));
    }

    // Specialization of expect()
    function expectChar(arg, msg) {
        if (input.charAt(i) === arg) {
            skipWhitespace(1);
            return arg;
        }
        error(msg || "expected '" + arg + "' got '" + input.charAt(i) + "'");
    }

    function error(msg, type) {
        var e = new Error(msg);
        e.index = i;
        e.type = type || 'Syntax';
        throw e;
    }

    // Same as $(), but don't change the state of the parser,
    // just return the match.
    function peek(tok) {
        if (typeof(tok) === 'string') {
            return input.charAt(i) === tok;
        } else {
            return tok.test(current);
        }
    }

    // Specialization of peek()
    function peekChar(tok) {
        return input.charAt(i) === tok;
    }


    function getInput(e, env) {
        if (e.filename && env.currentFileInfo.filename && (e.filename !== env.currentFileInfo.filename)) {
            return parser.imports.contents[e.filename];
        } else {
            return input;
        }
    }

    function getLocation(index, inputStream) {
        var n = index + 1,
            line = null,
            column = -1;

        while (--n >= 0 && inputStream.charAt(n) !== '\n') {
            column++;
        }

        if (typeof index === 'number') {
            line = (inputStream.slice(0, index).match(/\n/g) || "").length;
        }

        return {
            line: line,
            column: column
        };
    }

    function getDebugInfo(index, inputStream, env) {
        var filename = env.currentFileInfo.filename;
        if(less.mode !== 'browser' && less.mode !== 'rhino') {
            filename = require('path').resolve(filename);
        }

        return {
            lineNumber: getLocation(index, inputStream).line + 1,
            fileName: filename
        };
    }

    function LessError(e, env) {
        var input = getInput(e, env),
            loc = getLocation(e.index, input),
            line = loc.line,
            col  = loc.column,
            callLine = e.call && getLocation(e.call, input).line,
            lines = input.split('\n');

        this.type = e.type || 'Syntax';
        this.message = e.message;
        this.filename = e.filename || env.currentFileInfo.filename;
        this.index = e.index;
        this.line = typeof(line) === 'number' ? line + 1 : null;
        this.callLine = callLine + 1;
        this.callExtract = lines[callLine];
        this.stack = e.stack;
        this.column = col;
        this.extract = [
            lines[line - 1],
            lines[line],
            lines[line + 1]
        ];
    }

    LessError.prototype = new Error();
    LessError.prototype.constructor = LessError;

    this.env = env = env || {};

    // The optimization level dictates the thoroughness of the parser,
    // the lower the number, the less nodes it will create in the tree.
    // This could matter for debugging, or if you want to access
    // the individual nodes in the tree.
    this.optimization = ('optimization' in this.env) ? this.env.optimization : 1;

    //
    // The Parser
    //
    parser = {

        imports: imports,
        //
        // Parse an input string into an abstract syntax tree,
        // @param str A string containing 'less' markup
        // @param callback call `callback` when done.
        // @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
        //
        parse: function (str, callback, additionalData) {
            var root, line, lines, error = null, globalVars, modifyVars, preText = "";

            i = j = currentPos = furthest = 0;

            globalVars = (additionalData && additionalData.globalVars) ? less.Parser.serializeVars(additionalData.globalVars) + '\n' : '';
            modifyVars = (additionalData && additionalData.modifyVars) ? '\n' + less.Parser.serializeVars(additionalData.modifyVars) : '';

            if (globalVars || (additionalData && additionalData.banner)) {
                preText = ((additionalData && additionalData.banner) ? additionalData.banner : "") + globalVars;
                parser.imports.contentsIgnoredChars[env.currentFileInfo.filename] = preText.length;
            }

            str = str.replace(/\r\n/g, '\n');
            // Remove potential UTF Byte Order Mark
            input = str = preText + str.replace(/^\uFEFF/, '') + modifyVars;
            parser.imports.contents[env.currentFileInfo.filename] = str;

            // Split the input into chunks.
            chunks = (function (input) {
                var len = input.length, level = 0, parenLevel = 0,
                    lastOpening, lastClosing, lastMultiComment, lastMultiCommentEndBrace,
                    chunks = [], emitFrom = 0,
                    parserCurrentIndex, currentChunkStartIndex, cc, cc2, matched;

                function fail(msg, index) {
                    error = new(LessError)({
                        index: index || parserCurrentIndex,
                        type: 'Parse',
                        message: msg,
                        filename: env.currentFileInfo.filename
                    }, env);
                }

                function emitChunk(force) {
                    var len = parserCurrentIndex - emitFrom;
                    if (((len < 512) && !force) || !len) {
                        return;
                    }
                    chunks.push(input.slice(emitFrom, parserCurrentIndex + 1));
                    emitFrom = parserCurrentIndex + 1;
                }

                for (parserCurrentIndex = 0; parserCurrentIndex < len; parserCurrentIndex++) {
                    cc = input.charCodeAt(parserCurrentIndex);
                    if (((cc >= 97) && (cc <= 122)) || (cc < 34)) {
                        // a-z or whitespace
                        continue;
                    }

                    switch (cc) {
                        case 40:                        // (
                            parenLevel++; continue;
                        case 41:                        // )
                            parenLevel--; continue;
                        case 59:                        // ;
                            if (!parenLevel) { emitChunk(); }
                            continue;
                        case 123:                       // {
                            level++; lastOpening = parserCurrentIndex; continue;
                        case 125:                       // }
                            level--; lastClosing = parserCurrentIndex;
                            if (!level) { emitChunk(); }
                            continue;
                        case 92:                        // \
                            if (parserCurrentIndex < len - 1) { parserCurrentIndex++; continue; }
                            return fail("unescaped `\\`");
                        case 34:
                        case 39:
                        case 96:                        // ", ' and `
                            matched = 0;
                            currentChunkStartIndex = parserCurrentIndex;
                            for (parserCurrentIndex = parserCurrentIndex + 1; parserCurrentIndex < len; parserCurrentIndex++) {
                                cc2 = input.charCodeAt(parserCurrentIndex);
                                if (cc2 > 96) { continue; }
                                if (cc2 == cc) { matched = 1; break; }
                                if (cc2 == 92) {        // \
                                    if (parserCurrentIndex == len - 1) {
                                        return fail("unescaped `\\`");
                                    }
                                    parserCurrentIndex++;
                                }
                            }
                            if (matched) { continue; }
                            return fail("unmatched `" + String.fromCharCode(cc) + "`", currentChunkStartIndex);
                        case 47:                        // /, check for comment
                            if (parenLevel || (parserCurrentIndex == len - 1)) { continue; }
                            cc2 = input.charCodeAt(parserCurrentIndex + 1);
                            if (cc2 == 47) {
                                // //, find lnfeed
                                for (parserCurrentIndex = parserCurrentIndex + 2; parserCurrentIndex < len; parserCurrentIndex++) {
                                    cc2 = input.charCodeAt(parserCurrentIndex);
                                    if ((cc2 <= 13) && ((cc2 == 10) || (cc2 == 13))) { break; }
                                }
                            } else if (cc2 == 42) {
                                // /*, find */
                                lastMultiComment = currentChunkStartIndex = parserCurrentIndex;
                                for (parserCurrentIndex = parserCurrentIndex + 2; parserCurrentIndex < len - 1; parserCurrentIndex++) {
                                    cc2 = input.charCodeAt(parserCurrentIndex);
                                    if (cc2 == 125) { lastMultiCommentEndBrace = parserCurrentIndex; }
                                    if (cc2 != 42) { continue; }
                                    if (input.charCodeAt(parserCurrentIndex + 1) == 47) { break; }
                                }
                                if (parserCurrentIndex == len - 1) {
                                    return fail("missing closing `*/`", currentChunkStartIndex);
                                }
                            }
                            continue;
                        case 42:                       // *, check for unmatched */
                            if ((parserCurrentIndex < len - 1) && (input.charCodeAt(parserCurrentIndex + 1) == 47)) {
                                return fail("unmatched `/*`");
                            }
                            continue;
                    }
                }

                if (level !== 0) {
                    if (level > 0) {
                        if ((lastMultiComment > lastOpening) && (lastMultiCommentEndBrace > lastMultiComment)) {
                            return fail("missing closing `}` or `*/`", lastOpening);
                        } else {
                            return fail("missing closing `}`", lastOpening);
                        }
                    }
                    return fail("missing opening `{`", lastClosing);
                } else if (parenLevel !== 0) {
                    return fail((parenLevel > 0) ? "missing closing `)`" : "missing opening `(`");
                }

                emitChunk(true);
                return chunks;
            })(str);

            if (error) {
                return callback(new(LessError)(error, env));
            }

            current = chunks[0];

            // Start with the primary rule.
            // The whole syntax tree is held under a Ruleset node,
            // with the `root` property set to true, so no `{}` are
            // output. The callback is called when the input is parsed.
            try {
                root = new(tree.Ruleset)(null, this.parsers.primary());
                root.root = true;
                root.firstRoot = true;
            } catch (e) {
                return callback(new(LessError)(e, env));
            }

            root.toCSS = (function (evaluate) {
                return function (options, variables) {
                    options = options || {};
                    var evaldRoot,
                        css,
                        evalEnv = new tree.evalEnv(options);
                        
                    //
                    // Allows setting variables with a hash, so:
                    //
                    //   `{ color: new(tree.Color)('#f01') }` will become:
                    //
                    //   new(tree.Rule)('@color',
                    //     new(tree.Value)([
                    //       new(tree.Expression)([
                    //         new(tree.Color)('#f01')
                    //       ])
                    //     ])
                    //   )
                    //
                    if (typeof(variables) === 'object' && !Array.isArray(variables)) {
                        variables = Object.keys(variables).map(function (k) {
                            var value = variables[k];

                            if (! (value instanceof tree.Value)) {
                                if (! (value instanceof tree.Expression)) {
                                    value = new(tree.Expression)([value]);
                                }
                                value = new(tree.Value)([value]);
                            }
                            return new(tree.Rule)('@' + k, value, false, null, 0);
                        });
                        evalEnv.frames = [new(tree.Ruleset)(null, variables)];
                    }

                    try {
                        var preEvalVisitors = [],
                            visitors = [
                                new(tree.joinSelectorVisitor)(),
                                new(tree.processExtendsVisitor)(),
                                new(tree.toCSSVisitor)({compress: Boolean(options.compress)})
                            ], i, root = this;

                        if (options.plugins) {
                            for(i =0; i < options.plugins.length; i++) {
                                if (options.plugins[i].isPreEvalVisitor) {
                                    preEvalVisitors.push(options.plugins[i]);
                                } else {
                                    if (options.plugins[i].isPreVisitor) {
                                        visitors.splice(0, 0, options.plugins[i]);
                                    } else {
                                        visitors.push(options.plugins[i]);
                                    }
                                }
                            }
                        }

                        for(i = 0; i < preEvalVisitors.length; i++) {
                            preEvalVisitors[i].run(root);
                        }

                        evaldRoot = evaluate.call(root, evalEnv);

                        for(i = 0; i < visitors.length; i++) {
                            visitors[i].run(evaldRoot);
                        }

                        if (options.sourceMap) {
                            evaldRoot = new tree.sourceMapOutput(
                                {
                                    contentsIgnoredCharsMap: parser.imports.contentsIgnoredChars,
                                    writeSourceMap: options.writeSourceMap,
                                    rootNode: evaldRoot,
                                    contentsMap: parser.imports.contents,
                                    sourceMapFilename: options.sourceMapFilename,
                                    sourceMapURL: options.sourceMapURL,
                                    outputFilename: options.sourceMapOutputFilename,
                                    sourceMapBasepath: options.sourceMapBasepath,
                                    sourceMapRootpath: options.sourceMapRootpath,
                                    outputSourceFiles: options.outputSourceFiles,
                                    sourceMapGenerator: options.sourceMapGenerator
                                });
                        }

                        css = evaldRoot.toCSS({
                                compress: Boolean(options.compress),
                                dumpLineNumbers: env.dumpLineNumbers,
                                strictUnits: Boolean(options.strictUnits)});
                    } catch (e) {
                        throw new(LessError)(e, env);
                    }

                    if (options.cleancss && less.mode === 'node') {
                        var CleanCSS = require('clean-css'),
                            cleancssOptions = options.cleancssOptions || {};

                        if (cleancssOptions.keepSpecialComments === undefined) {
                            cleancssOptions.keepSpecialComments = "*";
                        }
                        cleancssOptions.processImport = false;
                        cleancssOptions.noRebase = true;
                        if (cleancssOptions.noAdvanced === undefined) {
                            cleancssOptions.noAdvanced = true;
                        }

                        return new CleanCSS(cleancssOptions).minify(css);
                    } else if (options.compress) {
                        return css.replace(/(^(\s)+)|((\s)+$)/g, "");
                    } else {
                        return css;
                    }
                };
            })(root.eval);

            // If `i` is smaller than the `input.length - 1`,
            // it means the parser wasn't able to parse the whole
            // string, so we've got a parsing error.
            //
            // We try to extract a \n delimited string,
            // showing the line where the parse error occured.
            // We split it up into two parts (the part which parsed,
            // and the part which didn't), so we can color them differently.
            if (i < input.length - 1) {
                i = furthest;
                var loc = getLocation(i, input);
                lines = input.split('\n');
                line = loc.line + 1;

                error = {
                    type: "Parse",
                    message: "Unrecognised input",
                    index: i,
                    filename: env.currentFileInfo.filename,
                    line: line,
                    column: loc.column,
                    extract: [
                        lines[line - 2],
                        lines[line - 1],
                        lines[line]
                    ]
                };
            }

            var finish = function (e) {
                e = error || e || parser.imports.error;

                if (e) {
                    if (!(e instanceof LessError)) {
                        e = new(LessError)(e, env);
                    }

                    return callback(e);
                }
                else {
                    return callback(null, root);
                }
            };

            if (env.processImports !== false) {
                new tree.importVisitor(this.imports, finish)
                    .run(root);
            } else {
                return finish();
            }
        },

        //
        // Here in, the parsing rules/functions
        //
        // The basic structure of the syntax tree generated is as follows:
        //
        //   Ruleset ->  Rule -> Value -> Expression -> Entity
        //
        // Here's some LESS code:
        //
        //    .class {
        //      color: #fff;
        //      border: 1px solid #000;
        //      width: @w + 4px;
        //      > .child {...}
        //    }
        //
        // And here's what the parse tree might look like:
        //
        //     Ruleset (Selector '.class', [
        //         Rule ("color",  Value ([Expression [Color #fff]]))
        //         Rule ("border", Value ([Expression [Dimension 1px][Keyword "solid"][Color #000]]))
        //         Rule ("width",  Value ([Expression [Operation "+" [Variable "@w"][Dimension 4px]]]))
        //         Ruleset (Selector [Element '>', '.child'], [...])
        //     ])
        //
        //  In general, most rules will try to parse a token with the `$()` function, and if the return
        //  value is truly, will return a new node, of the relevant type. Sometimes, we need to check
        //  first, before parsing, that's when we use `peek()`.
        //
        parsers: parsers = {
            //
            // The `primary` rule is the *entry* and *exit* point of the parser.
            // The rules here can appear at any level of the parse tree.
            //
            // The recursive nature of the grammar is an interplay between the `block`
            // rule, which represents `{ ... }`, the `ruleset` rule, and this `primary` rule,
            // as represented by this simplified grammar:
            //
            //     primary  →  (ruleset | rule)+
            //     ruleset  →  selector+ block
            //     block    →  '{' primary '}'
            //
            // Only at one point is the primary rule not called from the
            // block rule: at the root level.
            //
            primary: function () {
                var mixin = this.mixin, $re = _$re, root = [], node;

                while (true)
                {
                    node = this.extendRule() || mixin.definition() || this.rule() || this.ruleset() ||
                        mixin.call() || this.comment() || this.directive();
                    if (node) {
                        root.push(node);
                    } else {
                        if (!($re(/^[\s\n]+/) || $re(/^;+/))) {
                            break;
                        }
                    }
                }

                return root;
            },

            // We create a Comment node for CSS comments `/* */`,
            // but keep the LeSS comments `//` silent, by just skipping
            // over them.
            comment: function () {
                var comment;

                if (input.charAt(i) !== '/') { return; }

                if (input.charAt(i + 1) === '/') {
                    return new(tree.Comment)($re(/^\/\/.*/), true, i, env.currentFileInfo);
                }
                comment = $re(/^\/\*(?:[^*]|\*+[^\/*])*\*+\/\n?/);
                if (comment) {
                    return new(tree.Comment)(comment, false, i, env.currentFileInfo);
                }
            },

            comments: function () {
                var comment, comments = [];

                while(true) {
                    comment = this.comment();
                    if (!comment) {
                        break;
                    }
                    comments.push(comment);
                }

                return comments;
            },

            //
            // Entities are tokens which can be found inside an Expression
            //
            entities: {
                //
                // A string, which supports escaping " and '
                //
                //     "milky way" 'he\'s the one!'
                //
                quoted: function () {
                    var str, j = i, e, index = i;

                    if (input.charAt(j) === '~') { j++; e = true; } // Escaped strings
                    if (input.charAt(j) !== '"' && input.charAt(j) !== "'") { return; }

                    if (e) { $char('~'); }

                    str = $re(/^"((?:[^"\\\r\n]|\\.)*)"|'((?:[^'\\\r\n]|\\.)*)'/);
                    if (str) {
                        return new(tree.Quoted)(str[0], str[1] || str[2], e, index, env.currentFileInfo);
                    }
                },

                //
                // A catch-all word, such as:
                //
                //     black border-collapse
                //
                keyword: function () {
                    var k;

                    k = $re(/^[_A-Za-z-][_A-Za-z0-9-]*/);
                    if (k) {
                        var color = tree.Color.fromKeyword(k);
                        if (color) {
                            return color;
                        }
                        return new(tree.Keyword)(k);
                    }
                },

                //
                // A function call
                //
                //     rgb(255, 0, 255)
                //
                // We also try to catch IE's `alpha()`, but let the `alpha` parser
                // deal with the details.
                //
                // The arguments are parsed with the `entities.arguments` parser.
                //
                call: function () {
                    var name, nameLC, args, alpha_ret, index = i;

                    name = /^([\w-]+|%|progid:[\w\.]+)\(/.exec(current);
                    if (!name) { return; }

                    name = name[1];
                    nameLC = name.toLowerCase();
                    if (nameLC === 'url') {
                        return null;
                    }

                    i += name.length;

                    if (nameLC === 'alpha') {
                        alpha_ret = parsers.alpha();
                        if(typeof alpha_ret !== 'undefined') {
                            return alpha_ret;
                        }
                    }

                    $char('('); // Parse the '(' and consume whitespace.

                    args = this.arguments();

                    if (! $char(')')) {
                        return;
                    }

                    if (name) { return new(tree.Call)(name, args, index, env.currentFileInfo); }
                },
                arguments: function () {
                    var args = [], arg;

                    while (true) {
                        arg = this.assignment() || parsers.expression();
                        if (!arg) {
                            break;
                        }
                        args.push(arg);
                        if (! $char(',')) {
                            break;
                        }
                    }
                    return args;
                },
                literal: function () {
                    return this.dimension() ||
                           this.color() ||
                           this.quoted() ||
                           this.unicodeDescriptor();
                },

                // Assignments are argument entities for calls.
                // They are present in ie filter properties as shown below.
                //
                //     filter: progid:DXImageTransform.Microsoft.Alpha( *opacity=50* )
                //

                assignment: function () {
                    var key, value;
                    key = $re(/^\w+(?=\s?=)/i);
                    if (!key) {
                        return;
                    }
                    if (!$char('=')) {
                        return;
                    }
                    value = parsers.entity();
                    if (value) {
                        return new(tree.Assignment)(key, value);
                    }
                },

                //
                // Parse url() tokens
                //
                // We use a specific rule for urls, because they don't really behave like
                // standard function calls. The difference is that the argument doesn't have
                // to be enclosed within a string, so it can't be parsed as an Expression.
                //
                url: function () {
                    var value;

                    if (input.charAt(i) !== 'u' || !$re(/^url\(/)) {
                        return;
                    }

                    value = this.quoted() || this.variable() ||
                            $re(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || "";

                    expectChar(')');

                    return new(tree.URL)((value.value != null || value instanceof tree.Variable)
                                        ? value : new(tree.Anonymous)(value), env.currentFileInfo);
                },

                //
                // A Variable entity, such as `@fink`, in
                //
                //     width: @fink + 2px
                //
                // We use a different parser for variable definitions,
                // see `parsers.variable`.
                //
                variable: function () {
                    var name, index = i;

                    if (input.charAt(i) === '@' && (name = $re(/^@@?[\w-]+/))) {
                        return new(tree.Variable)(name, index, env.currentFileInfo);
                    }
                },

                // A variable entity useing the protective {} e.g. @{var}
                variableCurly: function () {
                    var curly, index = i;

                    if (input.charAt(i) === '@' && (curly = $re(/^@\{([\w-]+)\}/))) {
                        return new(tree.Variable)("@" + curly[1], index, env.currentFileInfo);
                    }
                },

                //
                // A Hexadecimal color
                //
                //     #4F3C2F
                //
                // `rgb` and `hsl` colors are parsed through the `entities.call` parser.
                //
                color: function () {
                    var rgb;

                    if (input.charAt(i) === '#' && (rgb = $re(/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/))) {
                        return new(tree.Color)(rgb[1]);
                    }
                },

                //
                // A Dimension, that is, a number and a unit
                //
                //     0.5em 95%
                //
                dimension: function () {
                    var value, c = input.charCodeAt(i);
                    //Is the first char of the dimension 0-9, '.', '+' or '-'
                    if ((c > 57 || c < 43) || c === 47 || c == 44) {
                        return;
                    }

                    value = $re(/^([+-]?\d*\.?\d+)(%|[a-z]+)?/);
                    if (value) {
                        return new(tree.Dimension)(value[1], value[2]);
                    }
                },

                //
                // A unicode descriptor, as is used in unicode-range
                //
                // U+0??  or U+00A1-00A9
                //
                unicodeDescriptor: function () {
                    var ud;

                    ud = $re(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/);
                    if (ud) {
                        return new(tree.UnicodeDescriptor)(ud[0]);
                    }
                },

                //
                // JavaScript code to be evaluated
                //
                //     `window.location.href`
                //
                javascript: function () {
                    var str, j = i, e;

                    if (input.charAt(j) === '~') { j++; e = true; } // Escaped strings
                    if (input.charAt(j) !== '`') { return; }
                    if (env.javascriptEnabled !== undefined && !env.javascriptEnabled) {
                        error("You are using JavaScript, which has been disabled.");
                    }

                    if (e) { $char('~'); }

                    str = $re(/^`([^`]*)`/);
                    if (str) {
                        return new(tree.JavaScript)(str[1], i, e);
                    }
                }
            },

            //
            // The variable part of a variable definition. Used in the `rule` parser
            //
            //     @fink:
            //
            variable: function () {
                var name;

                if (input.charAt(i) === '@' && (name = $re(/^(@[\w-]+)\s*:/))) { return name[1]; }
            },

            //
            // extend syntax - used to extend selectors
            //
            extend: function(isRule) {
                var elements, e, index = i, option, extendList, extend;

                if (!(isRule ? $re(/^&:extend\(/) : $re(/^:extend\(/))) { return; }

                do {
                    option = null;
                    elements = null;
                    while (! (option = $re(/^(all)(?=\s*(\)|,))/))) {
                        e = this.element();
                        if (!e) { break; }
                        if (elements) { elements.push(e); } else { elements = [ e ]; }
                    }

                    option = option && option[1];

                    extend = new(tree.Extend)(new(tree.Selector)(elements), option, index);
                    if (extendList) { extendList.push(extend); } else { extendList = [ extend ]; }

                } while($char(","));
                
                expect(/^\)/);

                if (isRule) {
                    expect(/^;/);
                }

                return extendList;
            },

            //
            // extendRule - used in a rule to extend all the parent selectors
            //
            extendRule: function() {
                return this.extend(true);
            },
            
            //
            // Mixins
            //
            mixin: {
                //
                // A Mixin call, with an optional argument list
                //
                //     #mixins > .square(#fff);
                //     .rounded(4px, black);
                //     .button;
                //
                // The `while` loop is there because mixins can be
                // namespaced, but we only support the child and descendant
                // selector for now.
                //
                call: function () {
                    var s = input.charAt(i), important = false, index = i,
                        elements, elem, e, c, args;

                    if (s !== '.' && s !== '#') { return; }

                    save(); // stop us absorbing part of an invalid selector

                    while (true) {
                        e = $re(/^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/);
                        if (!e) {
                            break;
                        }
                        elem = new(tree.Element)(c, e, i, env.currentFileInfo);
                        if (elements) { elements.push(elem); } else { elements = [ elem ]; }
                        c = $char('>');
                    }
                    if ($char('(')) {
                        args = this.args(true).args;
                        expectChar(')');
                    }

                    if (parsers.important()) {
                        important = true;
                    }

                    if (elements && ($char(';') || peekChar('}'))) {
                        return new(tree.mixin.Call)(elements, args, index, env.currentFileInfo, important);
                    }

                    restore();
                },
                args: function (isCall) {
                    var parsers = parser.parsers, entities = parsers.entities,
                        returner = { args:null, variadic: false },
                        expressions = [], argsSemiColon = [], argsComma = [],
                        isSemiColonSeperated, expressionContainsNamed, name, nameLoop, value, arg;

                    while (true) {
                        if (isCall) {
                            arg = parsers.expression();
                        } else {
                            parsers.comments();
                            if (input.charAt(i) === '.' && $re(/^\.{3}/)) {
                                returner.variadic = true;
                                if ($char(";") && !isSemiColonSeperated) {
                                    isSemiColonSeperated = true;
                                }
                                (isSemiColonSeperated ? argsSemiColon : argsComma)
                                    .push({ variadic: true });
                                break;
                            }
                            arg = entities.variable() || entities.literal() || entities.keyword();
                        }

                        if (!arg) {
                            break;
                        }

                        nameLoop = null;
                        if (arg.throwAwayComments) {
                            arg.throwAwayComments();
                        }
                        value = arg;
                        var val = null;

                        if (isCall) {
                            // Variable
                            if (arg.value.length == 1) {
                                val = arg.value[0];
                            }
                        } else {
                            val = arg;
                        }

                        if (val && val instanceof tree.Variable) {
                            if ($char(':')) {
                                if (expressions.length > 0) {
                                    if (isSemiColonSeperated) {
                                        error("Cannot mix ; and , as delimiter types");
                                    }
                                    expressionContainsNamed = true;
                                }
                                value = expect(parsers.expression);
                                nameLoop = (name = val.name);
                            } else if (!isCall && $re(/^\.{3}/)) {
                                returner.variadic = true;
                                if ($char(";") && !isSemiColonSeperated) {
                                    isSemiColonSeperated = true;
                                }
                                (isSemiColonSeperated ? argsSemiColon : argsComma)
                                    .push({ name: arg.name, variadic: true });
                                break;
                            } else if (!isCall) {
                                name = nameLoop = val.name;
                                value = null;
                            }
                        }

                        if (value) {
                            expressions.push(value);
                        }

                        argsComma.push({ name:nameLoop, value:value });

                        if ($char(',')) {
                            continue;
                        }

                        if ($char(';') || isSemiColonSeperated) {

                            if (expressionContainsNamed) {
                                error("Cannot mix ; and , as delimiter types");
                            }

                            isSemiColonSeperated = true;

                            if (expressions.length > 1) {
                                value = new(tree.Value)(expressions);
                            }
                            argsSemiColon.push({ name:name, value:value });

                            name = null;
                            expressions = [];
                            expressionContainsNamed = false;
                        }
                    }

                    returner.args = isSemiColonSeperated ? argsSemiColon : argsComma;
                    return returner;
                },
                //
                // A Mixin definition, with a list of parameters
                //
                //     .rounded (@radius: 2px, @color) {
                //        ...
                //     }
                //
                // Until we have a finer grained state-machine, we have to
                // do a look-ahead, to make sure we don't have a mixin call.
                // See the `rule` function for more information.
                //
                // We start by matching `.rounded (`, and then proceed on to
                // the argument list, which has optional default values.
                // We store the parameters in `params`, with a `value` key,
                // if there is a value, such as in the case of `@radius`.
                //
                // Once we've got our params list, and a closing `)`, we parse
                // the `{...}` block.
                //
                definition: function () {
                    var name, params = [], match, ruleset, cond, variadic = false;
                    if ((input.charAt(i) !== '.' && input.charAt(i) !== '#') ||
                        peek(/^[^{]*\}/)) {
                        return;
                    }

                    save();

                    match = $re(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/);
                    if (match) {
                        name = match[1];

                        var argInfo = this.args(false);
                        params = argInfo.args;
                        variadic = argInfo.variadic;

                        // .mixincall("@{a}");
                        // looks a bit like a mixin definition.. so we have to be nice and restore
                        if (!$char(')')) {
                            furthest = i;
                            restore();
                        }
                        
                        parsers.comments();

                        if ($re(/^when/)) { // Guard
                            cond = expect(parsers.conditions, 'expected condition');
                        }

                        ruleset = parsers.block();

                        if (ruleset) {
                            return new(tree.mixin.Definition)(name, params, ruleset, cond, variadic);
                        } else {
                            restore();
                        }
                    }
                }
            },

            //
            // Entities are the smallest recognized token,
            // and can be found inside a rule's value.
            //
            entity: function () {
                var entities = this.entities;

                return entities.literal() || entities.variable() || entities.url() ||
                       entities.call()    || entities.keyword()  || entities.javascript() ||
                       this.comment();
            },

            //
            // A Rule terminator. Note that we use `peek()` to check for '}',
            // because the `block` rule will be expecting it, but we still need to make sure
            // it's there, if ';' was ommitted.
            //
            end: function () {
                return $char(';') || peekChar('}');
            },

            //
            // IE's alpha function
            //
            //     alpha(opacity=88)
            //
            alpha: function () {
                var value;

                if (! $re(/^\(opacity=/i)) { return; }
                value = $re(/^\d+/) || this.entities.variable();
                if (value) {
                    expectChar(')');
                    return new(tree.Alpha)(value);
                }
            },

            //
            // A Selector Element
            //
            //     div
            //     + h1
            //     #socks
            //     input[type="text"]
            //
            // Elements are the building blocks for Selectors,
            // they are made out of a `Combinator` (see combinator rule),
            // and an element name, such as a tag a class, or `*`.
            //
            element: function () {
                var e, c, v;

                c = this.combinator();

                e = $re(/^(?:\d+\.\d+|\d+)%/) || $re(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) ||
                    $char('*') || $char('&') || this.attribute() || $re(/^\([^()@]+\)/) || $re(/^[\.#](?=@)/) ||
                    this.entities.variableCurly();

                if (! e) {
                    if ($char('(')) {
                        if ((v = this.selector()) && $char(')')) {
                            e = new(tree.Paren)(v);
                        }
                    }
                }

                if (e) { return new(tree.Element)(c, e, i, env.currentFileInfo); }
            },

            //
            // Combinators combine elements together, in a Selector.
            //
            // Because our parser isn't white-space sensitive, special care
            // has to be taken, when parsing the descendant combinator, ` `,
            // as it's an empty space. We have to check the previous character
            // in the input, to see if it's a ` ` character. More info on how
            // we deal with this in *combinator.js*.
            //
            combinator: function () {
                var c = input.charAt(i);

                if (c === '>' || c === '+' || c === '~' || c === '|') {
                    i++;
                    while (isWhitespace(input, i)) { i++; }
                    return new(tree.Combinator)(c);
                } else if (isWhitespace(input, i - 1)) {
                    return new(tree.Combinator)(" ");
                } else {
                    return new(tree.Combinator)(null);
                }
            },
            //
            // A CSS selector (see selector below)
            // with less extensions e.g. the ability to extend and guard
            //
            lessSelector: function () {
                return this.selector(true);
            },
            //
            // A CSS Selector
            //
            //     .class > div + h1
            //     li a:hover
            //
            // Selectors are made out of one or more Elements, see above.
            //
            selector: function (isLess) {
                var $re = _$re, elements, extendList, c, e, extend, when, condition;

                while ((isLess && (extend = this.extend())) || (isLess && (when = $re(/^when/))) || (e = this.element())) {
                    if (when) {
                        condition = expect(this.conditions, 'expected condition');
                    } else if (condition) {
                        error("CSS guard can only be used at the end of selector");
                    } else if (extend) {
                        if (extendList) { extendList.push(extend); } else { extendList = [ extend ]; }
                    } else {
                        if (extendList) { error("Extend can only be used at the end of selector"); }
                        c = input.charAt(i);
                        if (elements) { elements.push(e); } else { elements = [ e ]; }
                        e = null;
                    }
                    if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') {
                        break;
                    }
                }

                if (elements) { return new(tree.Selector)(elements, extendList, condition, i, env.currentFileInfo); }
                if (extendList) { error("Extend must be used to extend a selector, it cannot be used on its own"); }
            },
            attribute: function () {
                if (! $char('[')) { return; }

                var entities = this.entities,
                    key, val, op;

                if (!(key = entities.variableCurly())) {
                    key = expect(/^(?:[_A-Za-z0-9-\*]*\|)?(?:[_A-Za-z0-9-]|\\.)+/);
                }

                op = $re(/^[|~*$^]?=/);
                if (op) {
                    val = entities.quoted() || $re(/^[0-9]+%/) || $re(/^[\w-]+/) || entities.variableCurly();
                }

                expectChar(']');

                return new(tree.Attribute)(key, op, val);
            },

            //
            // The `block` rule is used by `ruleset` and `mixin.definition`.
            // It's a wrapper around the `primary` rule, with added `{}`.
            //
            block: function () {
                var content;
                if ($char('{') && (content = this.primary()) && $char('}')) {
                    return content;
                }
            },

            //
            // div, .class, body > p {...}
            //
            ruleset: function () {
                var selectors, s, rules, debugInfo;
                
                save();

                if (env.dumpLineNumbers) {
                    debugInfo = getDebugInfo(i, input, env);
                }

                while (true) {
                    s = this.lessSelector();
                    if (!s) {
                        break;
                    }
                    if (selectors) { selectors.push(s); } else { selectors = [ s ]; }
                    this.comments();
                    if (! $char(',')) { break; }
                    if (s.condition) {
                        error("Guards are only currently allowed on a single selector.");
                    }
                    this.comments();
                }

                if (selectors && (rules = this.block())) {
                    var ruleset = new(tree.Ruleset)(selectors, rules, env.strictImports);
                    if (env.dumpLineNumbers) {
                        ruleset.debugInfo = debugInfo;
                    }
                    return ruleset;
                } else {
                    // Backtrack
                    furthest = i;
                    restore();
                }
            },
            rule: function (tryAnonymous) {
                var name, value, c = input.charAt(i), important, merge = false;
                save();

                if (c === '.' || c === '#' || c === '&') { return; }

                name = this.variable() || this.ruleProperty();
                if (name) {
                    // prefer to try to parse first if its a variable or we are compressing
                    // but always fallback on the other one
                    value = !tryAnonymous && (env.compress || (name.charAt && (name.charAt(0) === '@'))) ?
                        (this.value() || this.anonymousValue()) :
                        (this.anonymousValue() || this.value());

                    important = this.important();
                    
                    // a name returned by this.ruleProperty() is always an array of the form:
                    // ["", "string-1", ..., "string-n", ""] or ["", "string-1", ..., "string-n", "+"]
                    merge = name.pop && (name.pop() === "+");

                    if (value && this.end()) {
                        return new (tree.Rule)(name, value, important, merge, memo, env.currentFileInfo);
                    } else {
                        furthest = i;
                        restore();
                        if (value && !tryAnonymous) {
                            return this.rule(true);
                        }
                    }
                }
            },
            anonymousValue: function () {
                var match;
                match = /^([^@+\/'"*`(;{}-]*);/.exec(current);
                if (match) {
                    i += match[0].length - 1;
                    return new(tree.Anonymous)(match[1]);
                }
            },

            //
            // An @import directive
            //
            //     @import "lib";
            //
            // Depending on our environemnt, importing is done differently:
            // In the browser, it's an XHR request, in Node, it would be a
            // file-system operation. The function used for importing is
            // stored in `import`, which we pass to the Import constructor.
            //
            "import": function () {
                var path, features, index = i;

                save();

                var dir = $re(/^@import?\s+/);

                var options = (dir ? this.importOptions() : null) || {};

                if (dir && (path = this.entities.quoted() || this.entities.url())) {
                    features = this.mediaFeatures();
                    if ($char(';')) {
                        features = features && new(tree.Value)(features);
                        return new(tree.Import)(path, features, options, index, env.currentFileInfo);
                    }
                }

                restore();
            },

            importOptions: function() {
                var o, options = {}, optionName, value;

                // list of options, surrounded by parens
                if (! $char('(')) { return null; }
                do {
                    o = this.importOption();
                    if (o) {
                        optionName = o;
                        value = true;
                        switch(optionName) {
                            case "css":
                                optionName = "less";
                                value = false;
                            break;
                            case "once":
                                optionName = "multiple";
                                value = false;
                            break;
                        }
                        options[optionName] = value;
                        if (! $char(',')) { break; }
                    }
                } while (o);
                expectChar(')');
                return options;
            },

            importOption: function() {
                var opt = $re(/^(less|css|multiple|once|inline|reference)/);
                if (opt) {
                    return opt[1];
                }
            },

            mediaFeature: function () {
                var entities = this.entities, nodes = [], e, p;
                do {
                    e = entities.keyword() || entities.variable();
                    if (e) {
                        nodes.push(e);
                    } else if ($char('(')) {
                        p = this.property();
                        e = this.value();
                        if ($char(')')) {
                            if (p && e) {
                                nodes.push(new(tree.Paren)(new(tree.Rule)(p, e, null, null, i, env.currentFileInfo, true)));
                            } else if (e) {
                                nodes.push(new(tree.Paren)(e));
                            } else {
                                return null;
                            }
                        } else { return null; }
                    }
                } while (e);

                if (nodes.length > 0) {
                    return new(tree.Expression)(nodes);
                }
            },

            mediaFeatures: function () {
                var entities = this.entities, features = [], e;
                do {
                    e = this.mediaFeature();
                    if (e) {
                        features.push(e);
                        if (! $char(',')) { break; }
                    } else {
                        e = entities.variable();
                        if (e) {
                            features.push(e);
                            if (! $char(',')) { break; }
                        }
                    }
                } while (e);

                return features.length > 0 ? features : null;
            },

            media: function () {
                var features, rules, media, debugInfo;

                if (env.dumpLineNumbers) {
                    debugInfo = getDebugInfo(i, input, env);
                }

                if ($re(/^@media/)) {
                    features = this.mediaFeatures();

                    rules = this.block();
                    if (rules) {
                        media = new(tree.Media)(rules, features, i, env.currentFileInfo);
                        if (env.dumpLineNumbers) {
                            media.debugInfo = debugInfo;
                        }
                        return media;
                    }
                }
            },

            //
            // A CSS Directive
            //
            //     @charset "utf-8";
            //
            directive: function () {
                var name, value, rules, nonVendorSpecificName,
                    hasBlock, hasIdentifier, hasExpression, identifier;

                if (input.charAt(i) !== '@') { return; }

                value = this['import']() || this.media();
                if (value) {
                    return value;
                }

                save();

                name = $re(/^@[a-z-]+/);
                
                if (!name) { return; }

                nonVendorSpecificName = name;
                if (name.charAt(1) == '-' && name.indexOf('-', 2) > 0) {
                    nonVendorSpecificName = "@" + name.slice(name.indexOf('-', 2) + 1);
                }

                switch(nonVendorSpecificName) {
                    case "@font-face":
                        hasBlock = true;
                        break;
                    case "@viewport":
                    case "@top-left":
                    case "@top-left-corner":
                    case "@top-center":
                    case "@top-right":
                    case "@top-right-corner":
                    case "@bottom-left":
                    case "@bottom-left-corner":
                    case "@bottom-center":
                    case "@bottom-right":
                    case "@bottom-right-corner":
                    case "@left-top":
                    case "@left-middle":
                    case "@left-bottom":
                    case "@right-top":
                    case "@right-middle":
                    case "@right-bottom":
                        hasBlock = true;
                        break;
                    case "@host":
                    case "@page":
                    case "@document":
                    case "@supports":
                    case "@keyframes":
                        hasBlock = true;
                        hasIdentifier = true;
                        break;
                    case "@namespace":
                        hasExpression = true;
                        break;
                }

                if (hasIdentifier) {
                    identifier = ($re(/^[^{]+/) || '').trim();
                    if (identifier) {
                        name += " " + identifier;
                    }
                }

                if (hasBlock) {
                    rules = this.block();
                    if (rules) {
                        return new(tree.Directive)(name, rules, i, env.currentFileInfo);
                    }
                } else {
                    value = hasExpression ? this.expression() : this.entity();
                    if (value && $char(';')) {
                        var directive = new(tree.Directive)(name, value, i, env.currentFileInfo);
                        if (env.dumpLineNumbers) {
                            directive.debugInfo = getDebugInfo(i, input, env);
                        }
                        return directive;
                    }
                }

                restore();
            },

            //
            // A Value is a comma-delimited list of Expressions
            //
            //     font-family: Baskerville, Georgia, serif;
            //
            // In a Rule, a Value represents everything after the `:`,
            // and before the `;`.
            //
            value: function () {
                var e, expressions = [];

                do {
                    e = this.expression();
                    if (e) {
                        expressions.push(e);
                        if (! $char(',')) { break; }
                    }
                } while(e);

                if (expressions.length > 0) {
                    return new(tree.Value)(expressions);
                }
            },
            important: function () {
                if (input.charAt(i) === '!') {
                    return $re(/^! *important/);
                }
            },
            sub: function () {
                var a, e;

                if ($char('(')) {
                    a = this.addition();
                    if (a) {
                        e = new(tree.Expression)([a]);
                        expectChar(')');
                        e.parens = true;
                        return e;
                    }
                }
            },
            multiplication: function () {
                var m, a, op, operation, isSpaced;
                m = this.operand();
                if (m) {
                    isSpaced = isWhitespace(input, i - 1);
                    while (true) {
                        if (peek(/^\/[*\/]/)) {
                            break;
                        }
                        op = $char('/') || $char('*');

                        if (!op) { break; }

                        a = this.operand();

                        if (!a) { break; }

                        m.parensInOp = true;
                        a.parensInOp = true;
                        operation = new(tree.Operation)(op, [operation || m, a], isSpaced);
                        isSpaced = isWhitespace(input, i - 1);
                    }
                    return operation || m;
                }
            },
            addition: function () {
                var m, a, op, operation, isSpaced;
                m = this.multiplication();
                if (m) {
                    isSpaced = isWhitespace(input, i - 1);
                    while (true) {
                        op = $re(/^[-+]\s+/) || (!isSpaced && ($char('+') || $char('-')));
                        if (!op) {
                            break;
                        }
                        a = this.multiplication();
                        if (!a) {
                            break;
                        }
                        
                        m.parensInOp = true;
                        a.parensInOp = true;
                        operation = new(tree.Operation)(op, [operation || m, a], isSpaced);
                        isSpaced = isWhitespace(input, i - 1);
                    }
                    return operation || m;
                }
            },
            conditions: function () {
                var a, b, index = i, condition;

                a = this.condition();
                if (a) {
                    while (true) {
                        if (!peek(/^,\s*(not\s*)?\(/) || !$char(',')) {
                            break;
                        }
                        b = this.condition();
                        if (!b) {
                            break;
                        }
                        condition = new(tree.Condition)('or', condition || a, b, index);
                    }
                    return condition || a;
                }
            },
            condition: function () {
                var entities = this.entities, index = i, negate = false,
                    a, b, c, op;

                if ($re(/^not/)) { negate = true; }
                expectChar('(');
                a = this.addition() || entities.keyword() || entities.quoted();
                if (a) {
                    op = $re(/^(?:>=|<=|=<|[<=>])/);
                    if (op) {
                        b = this.addition() || entities.keyword() || entities.quoted();
                        if (b) {
                            c = new(tree.Condition)(op, a, b, index, negate);
                        } else {
                            error('expected expression');
                        }
                    } else {
                        c = new(tree.Condition)('=', a, new(tree.Keyword)('true'), index, negate);
                    }
                    expectChar(')');
                    return $re(/^and/) ? new(tree.Condition)('and', c, this.condition()) : c;
                }
            },

            //
            // An operand is anything that can be part of an operation,
            // such as a Color, or a Variable
            //
            operand: function () {
                var entities = this.entities,
                    p = input.charAt(i + 1), negate;

                if (input.charAt(i) === '-' && (p === '@' || p === '(')) { negate = $char('-'); }
                var o = this.sub() || entities.dimension() ||
                        entities.color() || entities.variable() ||
                        entities.call();

                if (negate) {
                    o.parensInOp = true;
                    o = new(tree.Negative)(o);
                }

                return o;
            },

            //
            // Expressions either represent mathematical operations,
            // or white-space delimited Entities.
            //
            //     1px solid black
            //     @var * 2
            //
            expression: function () {
                var entities = [], e, delim;

                do {
                    e = this.addition() || this.entity();
                    if (e) {
                        entities.push(e);
                        // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
                        if (!peek(/^\/[\/*]/)) {
                            delim = $char('/');
                            if (delim) {
                                entities.push(new(tree.Anonymous)(delim));
                            }
                        }
                    }
                } while (e);
                if (entities.length > 0) {
                    return new(tree.Expression)(entities);
                }
            },
            property: function () {
                var name = $re(/^(\*?-?[_a-zA-Z0-9-]+)\s*:/);
                if (name) {
                    return name[1];
                }
            },
            ruleProperty: function () {
                var c = current, name = [], index = [], length = 0;
                
                function match(re) {
                    var a = re.exec(c);
                    if (a) {
                        index.push(i + length);
                        length += a[0].length;
                        c = c.slice(a[1].length);
                        return name.push(a[1]);
                    }
                }

                match(/^(\*?)/);
                while (match(/^((?:[\w-]+)|(?:@\{[\w-]+\}))/)); // !
                if ((name.length > 1) && match(/^\s*(\+?)\s*:/)) {
                    // at last, we have the complete match now. move forward, 
                    // convert @{var}s to tree.Variable(s) and return:
                    skipWhitespace(length);
                    for (var k in name) {
                        if (name[k].charAt(0) === '@') {
                            name[k] = new tree.Variable('@' + name[k].slice(2, -1), 
                                index[k], env.currentFileInfo);
                        }
                    }
                    return name;
                }
            }
        }
    };
    return parser;
};
less.Parser.serializeVars = function(vars) {
    var s = '';

    for (var name in vars) {
        if (Object.hasOwnProperty.call(vars, name)) {
            var value = vars[name];
            s += ((name[0] === '@') ? '' : '@') + name +': '+ value +
                    ((('' + value).slice(-1) === ';') ? '' : ';');
        }
    }

    return s;
};
(function (tree) {

tree.functions = {
    rgb: function (r, g, b) {
        return this.rgba(r, g, b, 1.0);
    },
    rgba: function (r, g, b, a) {
        var rgb = [r, g, b].map(function (c) { return scaled(c, 255); });
        a = number(a);
        return new(tree.Color)(rgb, a);
    },
    hsl: function (h, s, l) {
        return this.hsla(h, s, l, 1.0);
    },
    hsla: function (h, s, l, a) {
        function hue(h) {
            h = h < 0 ? h + 1 : (h > 1 ? h - 1 : h);
            if      (h * 6 < 1) { return m1 + (m2 - m1) * h * 6; }
            else if (h * 2 < 1) { return m2; }
            else if (h * 3 < 2) { return m1 + (m2 - m1) * (2/3 - h) * 6; }
            else                { return m1; }
        }

        h = (number(h) % 360) / 360;
        s = clamp(number(s)); l = clamp(number(l)); a = clamp(number(a));

        var m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
        var m1 = l * 2 - m2;

        return this.rgba(hue(h + 1/3) * 255,
                         hue(h)       * 255,
                         hue(h - 1/3) * 255,
                         a);
    },

    hsv: function(h, s, v) {
        return this.hsva(h, s, v, 1.0);
    },

    hsva: function(h, s, v, a) {
        h = ((number(h) % 360) / 360) * 360;
        s = number(s); v = number(v); a = number(a);

        var i, f;
        i = Math.floor((h / 60) % 6);
        f = (h / 60) - i;

        var vs = [v,
                  v * (1 - s),
                  v * (1 - f * s),
                  v * (1 - (1 - f) * s)];
        var perm = [[0, 3, 1],
                    [2, 0, 1],
                    [1, 0, 3],
                    [1, 2, 0],
                    [3, 1, 0],
                    [0, 1, 2]];

        return this.rgba(vs[perm[i][0]] * 255,
                         vs[perm[i][1]] * 255,
                         vs[perm[i][2]] * 255,
                         a);
    },

    hue: function (color) {
        return new(tree.Dimension)(Math.round(color.toHSL().h));
    },
    saturation: function (color) {
        return new(tree.Dimension)(Math.round(color.toHSL().s * 100), '%');
    },
    lightness: function (color) {
        return new(tree.Dimension)(Math.round(color.toHSL().l * 100), '%');
    },
    hsvhue: function(color) {
        return new(tree.Dimension)(Math.round(color.toHSV().h));
    },
    hsvsaturation: function (color) {
        return new(tree.Dimension)(Math.round(color.toHSV().s * 100), '%');
    },
    hsvvalue: function (color) {
        return new(tree.Dimension)(Math.round(color.toHSV().v * 100), '%');
    },
    red: function (color) {
        return new(tree.Dimension)(color.rgb[0]);
    },
    green: function (color) {
        return new(tree.Dimension)(color.rgb[1]);
    },
    blue: function (color) {
        return new(tree.Dimension)(color.rgb[2]);
    },
    alpha: function (color) {
        return new(tree.Dimension)(color.toHSL().a);
    },
    luma: function (color) {
        return new(tree.Dimension)(Math.round(color.luma() * color.alpha * 100), '%');
    },
    saturate: function (color, amount) {
        // filter: saturate(3.2);
        // should be kept as is, so check for color
        if (!color.rgb) {
            return null;
        }
        var hsl = color.toHSL();

        hsl.s += amount.value / 100;
        hsl.s = clamp(hsl.s);
        return hsla(hsl);
    },
    desaturate: function (color, amount) {
        var hsl = color.toHSL();

        hsl.s -= amount.value / 100;
        hsl.s = clamp(hsl.s);
        return hsla(hsl);
    },
    lighten: function (color, amount) {
        var hsl = color.toHSL();

        hsl.l += amount.value / 100;
        hsl.l = clamp(hsl.l);
        return hsla(hsl);
    },
    darken: function (color, amount) {
        var hsl = color.toHSL();

        hsl.l -= amount.value / 100;
        hsl.l = clamp(hsl.l);
        return hsla(hsl);
    },
    fadein: function (color, amount) {
        var hsl = color.toHSL();

        hsl.a += amount.value / 100;
        hsl.a = clamp(hsl.a);
        return hsla(hsl);
    },
    fadeout: function (color, amount) {
        var hsl = color.toHSL();

        hsl.a -= amount.value / 100;
        hsl.a = clamp(hsl.a);
        return hsla(hsl);
    },
    fade: function (color, amount) {
        var hsl = color.toHSL();

        hsl.a = amount.value / 100;
        hsl.a = clamp(hsl.a);
        return hsla(hsl);
    },
    spin: function (color, amount) {
        var hsl = color.toHSL();
        var hue = (hsl.h + amount.value) % 360;

        hsl.h = hue < 0 ? 360 + hue : hue;

        return hsla(hsl);
    },
    //
    // Copyright (c) 2006-2009 Hampton Catlin, Nathan Weizenbaum, and Chris Eppstein
    // http://sass-lang.com
    //
    mix: function (color1, color2, weight) {
        if (!weight) {
            weight = new(tree.Dimension)(50);
        }
        var p = weight.value / 100.0;
        var w = p * 2 - 1;
        var a = color1.toHSL().a - color2.toHSL().a;

        var w1 = (((w * a == -1) ? w : (w + a) / (1 + w * a)) + 1) / 2.0;
        var w2 = 1 - w1;

        var rgb = [color1.rgb[0] * w1 + color2.rgb[0] * w2,
                   color1.rgb[1] * w1 + color2.rgb[1] * w2,
                   color1.rgb[2] * w1 + color2.rgb[2] * w2];

        var alpha = color1.alpha * p + color2.alpha * (1 - p);

        return new(tree.Color)(rgb, alpha);
    },
    greyscale: function (color) {
        return this.desaturate(color, new(tree.Dimension)(100));
    },
    contrast: function (color, dark, light, threshold) {
        // filter: contrast(3.2);
        // should be kept as is, so check for color
        if (!color.rgb) {
            return null;
        }
        if (typeof light === 'undefined') {
            light = this.rgba(255, 255, 255, 1.0);
        }
        if (typeof dark === 'undefined') {
            dark = this.rgba(0, 0, 0, 1.0);
        }
        //Figure out which is actually light and dark!
        if (dark.luma() > light.luma()) {
            var t = light;
            light = dark;
            dark = t;
        }
        if (typeof threshold === 'undefined') {
            threshold = 0.43;
        } else {
            threshold = number(threshold);
        }
        if (color.luma() < threshold) {
            return light;
        } else {
            return dark;
        }
    },
    e: function (str) {
        return new(tree.Anonymous)(str instanceof tree.JavaScript ? str.evaluated : str);
    },
    escape: function (str) {
        return new(tree.Anonymous)(encodeURI(str.value).replace(/=/g, "%3D").replace(/:/g, "%3A").replace(/#/g, "%23").replace(/;/g, "%3B").replace(/\(/g, "%28").replace(/\)/g, "%29"));
    },
    '%': function (quoted /* arg, arg, ...*/) {
        var args = Array.prototype.slice.call(arguments, 1),
            str = quoted.value;

        for (var i = 0; i < args.length; i++) {
            /*jshint loopfunc:true */
            str = str.replace(/%[sda]/i, function(token) {
                var value = token.match(/s/i) ? args[i].value : args[i].toCSS();
                return token.match(/[A-Z]$/) ? encodeURIComponent(value) : value;
            });
        }
        str = str.replace(/%%/g, '%');
        return new(tree.Quoted)('"' + str + '"', str);
    },
    unit: function (val, unit) {
        if(!(val instanceof tree.Dimension)) {
            throw { type: "Argument", message: "the first argument to unit must be a number" + (val instanceof tree.Operation ? ". Have you forgotten parenthesis?" : "") };
        }
        return new(tree.Dimension)(val.value, unit ? unit.toCSS() : "");
    },
    convert: function (val, unit) {
        return val.convertTo(unit.value);
    },
    round: function (n, f) {
        var fraction = typeof(f) === "undefined" ? 0 : f.value;
        return _math(function(num) { return num.toFixed(fraction); }, null, n);
    },
    pi: function () {
        return new(tree.Dimension)(Math.PI);
    },
    mod: function(a, b) {
        return new(tree.Dimension)(a.value % b.value, a.unit);
    },
    pow: function(x, y) {
        if (typeof x === "number" && typeof y === "number") {
            x = new(tree.Dimension)(x);
            y = new(tree.Dimension)(y);
        } else if (!(x instanceof tree.Dimension) || !(y instanceof tree.Dimension)) {
            throw { type: "Argument", message: "arguments must be numbers" };
        }

        return new(tree.Dimension)(Math.pow(x.value, y.value), x.unit);
    },
    _minmax: function (isMin, args) {
        args = Array.prototype.slice.call(args);
        switch(args.length) {
        case 0: throw { type: "Argument", message: "one or more arguments required" };
        case 1: return args[0];
        }
        var i, j, current, currentUnified, referenceUnified, unit,
            order  = [], // elems only contains original argument values.
            values = {}; // key is the unit.toString() for unified tree.Dimension values,
                         // value is the index into the order array.
        for (i = 0; i < args.length; i++) {
            current = args[i];
            if (!(current instanceof tree.Dimension)) {
                order.push(current);
                continue;
            }
            currentUnified = current.unify();
            unit = currentUnified.unit.toString();
            j = values[unit];
            if (j === undefined) {
                values[unit] = order.length;
                order.push(current);
                continue;
            }
            referenceUnified = order[j].unify();
            if ( isMin && currentUnified.value < referenceUnified.value ||
                !isMin && currentUnified.value > referenceUnified.value) {
                order[j] = current;
            }
        }
        if (order.length == 1) {
            return order[0];
        }
        args = order.map(function (a) { return a.toCSS(this.env); })
                    .join(this.env.compress ? "," : ", ");
        return new(tree.Anonymous)((isMin ? "min" : "max") + "(" + args + ")");
    },
    min: function () {
        return this._minmax(true, arguments);
    },
    max: function () {
        return this._minmax(false, arguments);
    },
    argb: function (color) {
        return new(tree.Anonymous)(color.toARGB());
    },
    percentage: function (n) {
        return new(tree.Dimension)(n.value * 100, '%');
    },
    color: function (n) {
        if (n instanceof tree.Quoted) {
            var colorCandidate = n.value,
                returnColor;
            returnColor = tree.Color.fromKeyword(colorCandidate);
            if (returnColor) {
                return returnColor;
            }
            if (/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/.test(colorCandidate)) {
                return new(tree.Color)(colorCandidate.slice(1));
            }
            throw { type: "Argument", message: "argument must be a color keyword or 3/6 digit hex e.g. #FFF" };
        } else {
            throw { type: "Argument", message: "argument must be a string" };
        }
    },
    iscolor: function (n) {
        return this._isa(n, tree.Color);
    },
    isnumber: function (n) {
        return this._isa(n, tree.Dimension);
    },
    isstring: function (n) {
        return this._isa(n, tree.Quoted);
    },
    iskeyword: function (n) {
        return this._isa(n, tree.Keyword);
    },
    isurl: function (n) {
        return this._isa(n, tree.URL);
    },
    ispixel: function (n) {
        return this.isunit(n, 'px');
    },
    ispercentage: function (n) {
        return this.isunit(n, '%');
    },
    isem: function (n) {
        return this.isunit(n, 'em');
    },
    isunit: function (n, unit) {
        return (n instanceof tree.Dimension) && n.unit.is(unit.value || unit) ? tree.True : tree.False;
    },
    _isa: function (n, Type) {
        return (n instanceof Type) ? tree.True : tree.False;
    },
    tint: function(color, amount) {
        return this.mix(this.rgb(255,255,255), color, amount);
    },
    shade: function(color, amount) {
        return this.mix(this.rgb(0, 0, 0), color, amount);
    },   
    extract: function(values, index) {
        index = index.value - 1; // (1-based index)       
        // handle non-array values as an array of length 1
        // return 'undefined' if index is invalid
        return Array.isArray(values.value) 
            ? values.value[index] : Array(values)[index];
    },
    length: function(values) {
        var n = Array.isArray(values.value) ? values.value.length : 1;
        return new tree.Dimension(n);
    },

    "data-uri": function(mimetypeNode, filePathNode) {

        if (typeof window !== 'undefined') {
            return new tree.URL(filePathNode || mimetypeNode, this.currentFileInfo).eval(this.env);
        }

        var mimetype = mimetypeNode.value;
        var filePath = (filePathNode && filePathNode.value);

        var fs = require("fs"),
            path = require("path"),
            useBase64 = false;

        if (arguments.length < 2) {
            filePath = mimetype;
        }

        if (this.env.isPathRelative(filePath)) {
            if (this.currentFileInfo.relativeUrls) {
                filePath = path.join(this.currentFileInfo.currentDirectory, filePath);
            } else {
                filePath = path.join(this.currentFileInfo.entryPath, filePath);
            }
        }

        // detect the mimetype if not given
        if (arguments.length < 2) {
            var mime;
            try {
                mime = require('mime');
            } catch (ex) {
                mime = tree._mime;
            }

            mimetype = mime.lookup(filePath);

            // use base 64 unless it's an ASCII or UTF-8 format
            var charset = mime.charsets.lookup(mimetype);
            useBase64 = ['US-ASCII', 'UTF-8'].indexOf(charset) < 0;
            if (useBase64) { mimetype += ';base64'; }
        }
        else {
            useBase64 = /;base64$/.test(mimetype);
        }

        var buf = fs.readFileSync(filePath);

        // IE8 cannot handle a data-uri larger than 32KB. If this is exceeded
        // and the --ieCompat flag is enabled, return a normal url() instead.
        var DATA_URI_MAX_KB = 32,
            fileSizeInKB = parseInt((buf.length / 1024), 10);
        if (fileSizeInKB >= DATA_URI_MAX_KB) {

            if (this.env.ieCompat !== false) {
                if (!this.env.silent) {
                    console.warn("Skipped data-uri embedding of %s because its size (%dKB) exceeds IE8-safe %dKB!", filePath, fileSizeInKB, DATA_URI_MAX_KB);
                }

                return new tree.URL(filePathNode || mimetypeNode, this.currentFileInfo).eval(this.env);
            }
        }

        buf = useBase64 ? buf.toString('base64')
                        : encodeURIComponent(buf);

        var uri = "'data:" + mimetype + ',' + buf + "'";
        return new(tree.URL)(new(tree.Anonymous)(uri));
    },

    "svg-gradient": function(direction) {

        function throwArgumentDescriptor() {
            throw { type: "Argument", message: "svg-gradient expects direction, start_color [start_position], [color position,]..., end_color [end_position]" };
        }

        if (arguments.length < 3) {
            throwArgumentDescriptor();
        }
        var stops = Array.prototype.slice.call(arguments, 1),
            gradientDirectionSvg,
            gradientType = "linear",
            rectangleDimension = 'x="0" y="0" width="1" height="1"',
            useBase64 = true,
            renderEnv = {compress: false},
            returner,
            directionValue = direction.toCSS(renderEnv),
            i, color, position, positionValue, alpha;

        switch (directionValue) {
            case "to bottom":
                gradientDirectionSvg = 'x1="0%" y1="0%" x2="0%" y2="100%"';
                break;
            case "to right":
                gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="0%"';
                break;
            case "to bottom right":
                gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="100%"';
                break;
            case "to top right":
                gradientDirectionSvg = 'x1="0%" y1="100%" x2="100%" y2="0%"';
                break;
            case "ellipse":
            case "ellipse at center":
                gradientType = "radial";
                gradientDirectionSvg = 'cx="50%" cy="50%" r="75%"';
                rectangleDimension = 'x="-50" y="-50" width="101" height="101"';
                break;
            default:
                throw { type: "Argument", message: "svg-gradient direction must be 'to bottom', 'to right', 'to bottom right', 'to top right' or 'ellipse at center'" };
        }
        returner = '<?xml version="1.0" ?>' +
            '<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="100%" height="100%" viewBox="0 0 1 1" preserveAspectRatio="none">' +
            '<' + gradientType + 'Gradient id="gradient" gradientUnits="userSpaceOnUse" ' + gradientDirectionSvg + '>';

        for (i = 0; i < stops.length; i+= 1) {
            if (stops[i].value) {
                color = stops[i].value[0];
                position = stops[i].value[1];
            } else {
                color = stops[i];
                position = undefined;
            }

            if (!(color instanceof tree.Color) || (!((i === 0 || i+1 === stops.length) && position === undefined) && !(position instanceof tree.Dimension))) {
                throwArgumentDescriptor();
            }
            positionValue = position ? position.toCSS(renderEnv) : i === 0 ? "0%" : "100%";
            alpha = color.alpha;
            returner += '<stop offset="' + positionValue + '" stop-color="' + color.toRGB() + '"' + (alpha < 1 ? ' stop-opacity="' + alpha + '"' : '') + '/>';
        }
        returner += '</' + gradientType + 'Gradient>' +
                    '<rect ' + rectangleDimension + ' fill="url(#gradient)" /></svg>';

        if (useBase64) {
            // only works in node, needs interface to what is supported in environment
            try {
                returner = new Buffer(returner).toString('base64');
            } catch(e) {
                useBase64 = false;
            }
        }

        returner = "'data:image/svg+xml" + (useBase64 ? ";base64" : "") + "," + returner + "'";
        return new(tree.URL)(new(tree.Anonymous)(returner));
    }
};

// these static methods are used as a fallback when the optional 'mime' dependency is missing
tree._mime = {
    // this map is intentionally incomplete
    // if you want more, install 'mime' dep
    _types: {
        '.htm' : 'text/html',
        '.html': 'text/html',
        '.gif' : 'image/gif',
        '.jpg' : 'image/jpeg',
        '.jpeg': 'image/jpeg',
        '.png' : 'image/png'
    },
    lookup: function (filepath) {
        var ext = require('path').extname(filepath),
            type = tree._mime._types[ext];
        if (type === undefined) {
            throw new Error('Optional dependency "mime" is required for ' + ext);
        }
        return type;
    },
    charsets: {
        lookup: function (type) {
            // assumes all text types are UTF-8
            return type && (/^text\//).test(type) ? 'UTF-8' : '';
        }
    }
};

// Math

var mathFunctions = {
 // name,  unit
    ceil:  null, 
    floor: null, 
    sqrt:  null, 
    abs:   null,
    tan:   "", 
    sin:   "", 
    cos:   "",
    atan:  "rad", 
    asin:  "rad", 
    acos:  "rad"
};

function _math(fn, unit, n) {
    if (!(n instanceof tree.Dimension)) {
        throw { type: "Argument", message: "argument must be a number" };
    }
    if (unit == null) {
        unit = n.unit;
    } else {
        n = n.unify();
    }
    return new(tree.Dimension)(fn(parseFloat(n.value)), unit);
}

// ~ End of Math

// Color Blending
// ref: http://www.w3.org/TR/compositing-1

function colorBlend(mode, color1, color2) {
    var ab = color1.alpha, cb, // backdrop
        as = color2.alpha, cs, // source
        ar, cr, r = [];        // result
        
    ar = as + ab * (1 - as);
    for (var i = 0; i < 3; i++) {
        cb = color1.rgb[i] / 255;
        cs = color2.rgb[i] / 255;
        cr = mode(cb, cs);
        if (ar) {
            cr = (as * cs + ab * (cb 
                - as * (cb + cs - cr))) / ar;
        }
        r[i] = cr * 255;
    }
    
    return new(tree.Color)(r, ar);
}

var colorBlendMode = {
    multiply: function(cb, cs) {
        return cb * cs;
    },
    screen: function(cb, cs) {
        return cb + cs - cb * cs;
    },   
    overlay: function(cb, cs) {
        cb *= 2;
        return (cb <= 1)
            ? colorBlendMode.multiply(cb, cs)
            : colorBlendMode.screen(cb - 1, cs);
    },
    softlight: function(cb, cs) {
        var d = 1, e = cb;
        if (cs > 0.5) {
            e = 1;
            d = (cb > 0.25) ? Math.sqrt(cb)
                : ((16 * cb - 12) * cb + 4) * cb;
        }            
        return cb - (1 - 2 * cs) * e * (d - cb);
    },
    hardlight: function(cb, cs) {
        return colorBlendMode.overlay(cs, cb);
    },
    difference: function(cb, cs) {
        return Math.abs(cb - cs);
    },
    exclusion: function(cb, cs) {
        return cb + cs - 2 * cb * cs;
    },

    // non-w3c functions:
    average: function(cb, cs) {
        return (cb + cs) / 2;
    },
    negation: function(cb, cs) {
        return 1 - Math.abs(cb + cs - 1);
    }
};

// ~ End of Color Blending

tree.defaultFunc = {
    eval: function () {
        var v = this.value_, e = this.error_;
        if (e) {
            throw e;
        }
        if (v != null) {
            return v ? tree.True : tree.False;
        }
    },
    value: function (v) {
        this.value_ = v;
    },
    error: function (e) {
        this.error_ = e;
    },
    reset: function () {
        this.value_ = this.error_ = null;
    }
};

function initFunctions() {
    var f, tf = tree.functions;
    
    // math
    for (f in mathFunctions) {
        tf[f] = _math.bind(null, Math[f], mathFunctions[f]);
    }
    
    // color blending
    for (f in colorBlendMode) {
        tf[f] = colorBlend.bind(null, colorBlendMode[f]);
    }
    
    // default
    f = tree.defaultFunc;
    tf.default = f.eval.bind(f);
    
} initFunctions();

function hsla(color) {
    return tree.functions.hsla(color.h, color.s, color.l, color.a);
}

function scaled(n, size) {
    if (n instanceof tree.Dimension && n.unit.is('%')) {
        return parseFloat(n.value * size / 100);
    } else {
        return number(n);
    }
}

function number(n) {
    if (n instanceof tree.Dimension) {
        return parseFloat(n.unit.is('%') ? n.value / 100 : n.value);
    } else if (typeof(n) === 'number') {
        return n;
    } else {
        throw {
            error: "RuntimeError",
            message: "color functions take numbers as parameters"
        };
    }
}

function clamp(val) {
    return Math.min(1, Math.max(0, val));
}

tree.functionCall = function(env, currentFileInfo) {
    this.env = env;
    this.currentFileInfo = currentFileInfo;
};

tree.functionCall.prototype = tree.functions;

})(require('./tree'));

(function (tree) {
    tree.colors = {
        'aliceblue':'#f0f8ff',
        'antiquewhite':'#faebd7',
        'aqua':'#00ffff',
        'aquamarine':'#7fffd4',
        'azure':'#f0ffff',
        'beige':'#f5f5dc',
        'bisque':'#ffe4c4',
        'black':'#000000',
        'blanchedalmond':'#ffebcd',
        'blue':'#0000ff',
        'blueviolet':'#8a2be2',
        'brown':'#a52a2a',
        'burlywood':'#deb887',
        'cadetblue':'#5f9ea0',
        'chartreuse':'#7fff00',
        'chocolate':'#d2691e',
        'coral':'#ff7f50',
        'cornflowerblue':'#6495ed',
        'cornsilk':'#fff8dc',
        'crimson':'#dc143c',
        'cyan':'#00ffff',
        'darkblue':'#00008b',
        'darkcyan':'#008b8b',
        'darkgoldenrod':'#b8860b',
        'darkgray':'#a9a9a9',
        'darkgrey':'#a9a9a9',
        'darkgreen':'#006400',
        'darkkhaki':'#bdb76b',
        'darkmagenta':'#8b008b',
        'darkolivegreen':'#556b2f',
        'darkorange':'#ff8c00',
        'darkorchid':'#9932cc',
        'darkred':'#8b0000',
        'darksalmon':'#e9967a',
        'darkseagreen':'#8fbc8f',
        'darkslateblue':'#483d8b',
        'darkslategray':'#2f4f4f',
        'darkslategrey':'#2f4f4f',
        'darkturquoise':'#00ced1',
        'darkviolet':'#9400d3',
        'deeppink':'#ff1493',
        'deepskyblue':'#00bfff',
        'dimgray':'#696969',
        'dimgrey':'#696969',
        'dodgerblue':'#1e90ff',
        'firebrick':'#b22222',
        'floralwhite':'#fffaf0',
        'forestgreen':'#228b22',
        'fuchsia':'#ff00ff',
        'gainsboro':'#dcdcdc',
        'ghostwhite':'#f8f8ff',
        'gold':'#ffd700',
        'goldenrod':'#daa520',
        'gray':'#808080',
        'grey':'#808080',
        'green':'#008000',
        'greenyellow':'#adff2f',
        'honeydew':'#f0fff0',
        'hotpink':'#ff69b4',
        'indianred':'#cd5c5c',
        'indigo':'#4b0082',
        'ivory':'#fffff0',
        'khaki':'#f0e68c',
        'lavender':'#e6e6fa',
        'lavenderblush':'#fff0f5',
        'lawngreen':'#7cfc00',
        'lemonchiffon':'#fffacd',
        'lightblue':'#add8e6',
        'lightcoral':'#f08080',
        'lightcyan':'#e0ffff',
        'lightgoldenrodyellow':'#fafad2',
        'lightgray':'#d3d3d3',
        'lightgrey':'#d3d3d3',
        'lightgreen':'#90ee90',
        'lightpink':'#ffb6c1',
        'lightsalmon':'#ffa07a',
        'lightseagreen':'#20b2aa',
        'lightskyblue':'#87cefa',
        'lightslategray':'#778899',
        'lightslategrey':'#778899',
        'lightsteelblue':'#b0c4de',
        'lightyellow':'#ffffe0',
        'lime':'#00ff00',
        'limegreen':'#32cd32',
        'linen':'#faf0e6',
        'magenta':'#ff00ff',
        'maroon':'#800000',
        'mediumaquamarine':'#66cdaa',
        'mediumblue':'#0000cd',
        'mediumorchid':'#ba55d3',
        'mediumpurple':'#9370d8',
        'mediumseagreen':'#3cb371',
        'mediumslateblue':'#7b68ee',
        'mediumspringgreen':'#00fa9a',
        'mediumturquoise':'#48d1cc',
        'mediumvioletred':'#c71585',
        'midnightblue':'#191970',
        'mintcream':'#f5fffa',
        'mistyrose':'#ffe4e1',
        'moccasin':'#ffe4b5',
        'navajowhite':'#ffdead',
        'navy':'#000080',
        'oldlace':'#fdf5e6',
        'olive':'#808000',
        'olivedrab':'#6b8e23',
        'orange':'#ffa500',
        'orangered':'#ff4500',
        'orchid':'#da70d6',
        'palegoldenrod':'#eee8aa',
        'palegreen':'#98fb98',
        'paleturquoise':'#afeeee',
        'palevioletred':'#d87093',
        'papayawhip':'#ffefd5',
        'peachpuff':'#ffdab9',
        'peru':'#cd853f',
        'pink':'#ffc0cb',
        'plum':'#dda0dd',
        'powderblue':'#b0e0e6',
        'purple':'#800080',
        'red':'#ff0000',
        'rosybrown':'#bc8f8f',
        'royalblue':'#4169e1',
        'saddlebrown':'#8b4513',
        'salmon':'#fa8072',
        'sandybrown':'#f4a460',
        'seagreen':'#2e8b57',
        'seashell':'#fff5ee',
        'sienna':'#a0522d',
        'silver':'#c0c0c0',
        'skyblue':'#87ceeb',
        'slateblue':'#6a5acd',
        'slategray':'#708090',
        'slategrey':'#708090',
        'snow':'#fffafa',
        'springgreen':'#00ff7f',
        'steelblue':'#4682b4',
        'tan':'#d2b48c',
        'teal':'#008080',
        'thistle':'#d8bfd8',
        'tomato':'#ff6347',
        'turquoise':'#40e0d0',
        'violet':'#ee82ee',
        'wheat':'#f5deb3',
        'white':'#ffffff',
        'whitesmoke':'#f5f5f5',
        'yellow':'#ffff00',
        'yellowgreen':'#9acd32'
    };
})(require('./tree'));

(function (tree) {

tree.debugInfo = function(env, ctx, lineSeperator) {
    var result="";
    if (env.dumpLineNumbers && !env.compress) {
        switch(env.dumpLineNumbers) {
            case 'comments':
                result = tree.debugInfo.asComment(ctx);
                break;
            case 'mediaquery':
                result = tree.debugInfo.asMediaQuery(ctx);
                break;
            case 'all':
                result = tree.debugInfo.asComment(ctx) + (lineSeperator || "") + tree.debugInfo.asMediaQuery(ctx);
                break;
        }
    }
    return result;
};

tree.debugInfo.asComment = function(ctx) {
    return '/* line ' + ctx.debugInfo.lineNumber + ', ' + ctx.debugInfo.fileName + ' */\n';
};

tree.debugInfo.asMediaQuery = function(ctx) {
    return '@media -sass-debug-info{filename{font-family:' +
        ('file://' + ctx.debugInfo.fileName).replace(/([.:/\\])/g, function (a) {
            if (a == '\\') {
                a = '\/';
            }
            return '\\' + a;
        }) +
        '}line{font-family:\\00003' + ctx.debugInfo.lineNumber + '}}\n';
};

tree.find = function (obj, fun) {
    for (var i = 0, r; i < obj.length; i++) {
        r = fun.call(obj, obj[i]);
        if (r) { return r; }
    }
    return null;
};

tree.jsify = function (obj) {
    if (Array.isArray(obj.value) && (obj.value.length > 1)) {
        return '[' + obj.value.map(function (v) { return v.toCSS(false); }).join(', ') + ']';
    } else {
        return obj.toCSS(false);
    }
};

tree.toCSS = function (env) {
    var strs = [];
    this.genCSS(env, {
        add: function(chunk, fileInfo, index) {
            strs.push(chunk);
        },
        isEmpty: function () {
            return strs.length === 0;
        }
    });
    return strs.join('');
};

tree.outputRuleset = function (env, output, rules) {
    var ruleCnt = rules.length, i;
    env.tabLevel = (env.tabLevel | 0) + 1;

    // Compressed
    if (env.compress) {
        output.add('{');
        for (i = 0; i < ruleCnt; i++) {
            rules[i].genCSS(env, output);
        }
        output.add('}');
        env.tabLevel--;
        return;
    }

    // Non-compressed
    var tabSetStr = '\n' + Array(env.tabLevel).join("  "), tabRuleStr = tabSetStr + "  ";
    if (!ruleCnt) {
        output.add(" {" + tabSetStr + '}');
    } else {
        output.add(" {" + tabRuleStr);
        rules[0].genCSS(env, output);
        for (i = 1; i < ruleCnt; i++) {
            output.add(tabRuleStr);
            rules[i].genCSS(env, output);
        }
        output.add(tabSetStr + '}');
    }

    env.tabLevel--;
};

})(require('./tree'));

(function (tree) {

tree.Alpha = function (val) {
    this.value = val;
};
tree.Alpha.prototype = {
    type: "Alpha",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    eval: function (env) {
        if (this.value.eval) { return new tree.Alpha(this.value.eval(env)); }
        return this;
    },
    genCSS: function (env, output) {
        output.add("alpha(opacity=");

        if (this.value.genCSS) {
            this.value.genCSS(env, output);
        } else {
            output.add(this.value);
        }

        output.add(")");
    },
    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {

tree.Anonymous = function (string, index, currentFileInfo, mapLines) {
    this.value = string.value || string;
    this.index = index;
    this.mapLines = mapLines;
    this.currentFileInfo = currentFileInfo;
};
tree.Anonymous.prototype = {
    type: "Anonymous",
    eval: function () { 
        return new tree.Anonymous(this.value, this.index, this.currentFileInfo, this.mapLines);
    },
    compare: function (x) {
        if (!x.toCSS) {
            return -1;
        }
        
        var left = this.toCSS(),
            right = x.toCSS();
        
        if (left === right) {
            return 0;
        }
        
        return left < right ? -1 : 1;
    },
    genCSS: function (env, output) {
        output.add(this.value, this.currentFileInfo, this.index, this.mapLines);
    },
    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {

tree.Assignment = function (key, val) {
    this.key = key;
    this.value = val;
};
tree.Assignment.prototype = {
    type: "Assignment",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    eval: function (env) {
        if (this.value.eval) {
            return new(tree.Assignment)(this.key, this.value.eval(env));
        }
        return this;
    },
    genCSS: function (env, output) {
        output.add(this.key + '=');
        if (this.value.genCSS) {
            this.value.genCSS(env, output);
        } else {
            output.add(this.value);
        }
    },
    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {

//
// A function call node.
//
tree.Call = function (name, args, index, currentFileInfo) {
    this.name = name;
    this.args = args;
    this.index = index;
    this.currentFileInfo = currentFileInfo;
};
tree.Call.prototype = {
    type: "Call",
    accept: function (visitor) {
        if (this.args) {
            this.args = visitor.visitArray(this.args);
        }
    },
    //
    // When evaluating a function call,
    // we either find the function in `tree.functions` [1],
    // in which case we call it, passing the  evaluated arguments,
    // if this returns null or we cannot find the function, we 
    // simply print it out as it appeared originally [2].
    //
    // The *functions.js* file contains the built-in functions.
    //
    // The reason why we evaluate the arguments, is in the case where
    // we try to pass a variable to a function, like: `saturate(@color)`.
    // The function should receive the value, not the variable.
    //
    eval: function (env) {
        var args = this.args.map(function (a) { return a.eval(env); }),
            nameLC = this.name.toLowerCase(),
            result, func;

        if (nameLC in tree.functions) { // 1.
            try {
                func = new tree.functionCall(env, this.currentFileInfo);
                result = func[nameLC].apply(func, args);
                if (result != null) {
                    return result;
                }
            } catch (e) {
                throw { type: e.type || "Runtime",
                        message: "error evaluating function `" + this.name + "`" +
                                 (e.message ? ': ' + e.message : ''),
                        index: this.index, filename: this.currentFileInfo.filename };
            }
        }

        return new tree.Call(this.name, args, this.index, this.currentFileInfo);
    },

    genCSS: function (env, output) {
        output.add(this.name + "(", this.currentFileInfo, this.index);

        for(var i = 0; i < this.args.length; i++) {
            this.args[i].genCSS(env, output);
            if (i + 1 < this.args.length) {
                output.add(", ");
            }
        }

        output.add(")");
    },

    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {
//
// RGB Colors - #ff0014, #eee
//
tree.Color = function (rgb, a) {
    //
    // The end goal here, is to parse the arguments
    // into an integer triplet, such as `128, 255, 0`
    //
    // This facilitates operations and conversions.
    //
    if (Array.isArray(rgb)) {
        this.rgb = rgb;
    } else if (rgb.length == 6) {
        this.rgb = rgb.match(/.{2}/g).map(function (c) {
            return parseInt(c, 16);
        });
    } else {
        this.rgb = rgb.split('').map(function (c) {
            return parseInt(c + c, 16);
        });
    }
    this.alpha = typeof(a) === 'number' ? a : 1;
};

var transparentKeyword = "transparent";

tree.Color.prototype = {
    type: "Color",
    eval: function () { return this; },
    luma: function () { return (0.2126 * this.rgb[0] / 255) + (0.7152 * this.rgb[1] / 255) + (0.0722 * this.rgb[2] / 255); },

    genCSS: function (env, output) {
        output.add(this.toCSS(env));
    },
    toCSS: function (env, doNotCompress) {
        var compress = env && env.compress && !doNotCompress;

        // If we have some transparency, the only way to represent it
        // is via `rgba`. Otherwise, we use the hex representation,
        // which has better compatibility with older browsers.
        // Values are capped between `0` and `255`, rounded and zero-padded.
        if (this.alpha < 1) {
            if (this.alpha === 0 && this.isTransparentKeyword) {
                return transparentKeyword;
            }
            return "rgba(" + this.rgb.map(function (c) {
                return clamp(Math.round(c), 255);
            }).concat(clamp(this.alpha, 1))
                .join(',' + (compress ? '' : ' ')) + ")";
        } else {
            var color = this.toRGB();

            if (compress) {
                var splitcolor = color.split('');

                // Convert color to short format
                if (splitcolor[1] === splitcolor[2] && splitcolor[3] === splitcolor[4] && splitcolor[5] === splitcolor[6]) {
                    color = '#' + splitcolor[1] + splitcolor[3] + splitcolor[5];
                }
            }

            return color;
        }
    },

    //
    // Operations have to be done per-channel, if not,
    // channels will spill onto each other. Once we have
    // our result, in the form of an integer triplet,
    // we create a new Color node to hold the result.
    //
    operate: function (env, op, other) {
        var rgb = [];
        var alpha = this.alpha * (1 - other.alpha) + other.alpha;
        for (var c = 0; c < 3; c++) {
            rgb[c] = tree.operate(env, op, this.rgb[c], other.rgb[c]);
        }
        return new(tree.Color)(rgb, alpha);
    },

    toRGB: function () {
        return toHex(this.rgb);
    },

    toHSL: function () {
        var r = this.rgb[0] / 255,
            g = this.rgb[1] / 255,
            b = this.rgb[2] / 255,
            a = this.alpha;

        var max = Math.max(r, g, b), min = Math.min(r, g, b);
        var h, s, l = (max + min) / 2, d = max - min;

        if (max === min) {
            h = s = 0;
        } else {
            s = l > 0.5 ? d / (2 - max - min) : d / (max + min);

            switch (max) {
                case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                case g: h = (b - r) / d + 2;               break;
                case b: h = (r - g) / d + 4;               break;
            }
            h /= 6;
        }
        return { h: h * 360, s: s, l: l, a: a };
    },
    //Adapted from http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
    toHSV: function () {
        var r = this.rgb[0] / 255,
            g = this.rgb[1] / 255,
            b = this.rgb[2] / 255,
            a = this.alpha;

        var max = Math.max(r, g, b), min = Math.min(r, g, b);
        var h, s, v = max;

        var d = max - min;
        if (max === 0) {
            s = 0;
        } else {
            s = d / max;
        }

        if (max === min) {
            h = 0;
        } else {
            switch(max){
                case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                case g: h = (b - r) / d + 2; break;
                case b: h = (r - g) / d + 4; break;
            }
            h /= 6;
        }
        return { h: h * 360, s: s, v: v, a: a };
    },
    toARGB: function () {
        return toHex([this.alpha * 255].concat(this.rgb));
    },
    compare: function (x) {
        if (!x.rgb) {
            return -1;
        }
        
        return (x.rgb[0] === this.rgb[0] &&
            x.rgb[1] === this.rgb[1] &&
            x.rgb[2] === this.rgb[2] &&
            x.alpha === this.alpha) ? 0 : -1;
    }
};

tree.Color.fromKeyword = function(keyword) {
    if (tree.colors.hasOwnProperty(keyword)) {
        // detect named color
        return new(tree.Color)(tree.colors[keyword].slice(1));
    }
    if (keyword === transparentKeyword) {
        var transparent = new(tree.Color)([0, 0, 0], 0);
        transparent.isTransparentKeyword = true;
        return transparent;
    }
};

function toHex(v) {
    return '#' + v.map(function (c) {
        c = clamp(Math.round(c), 255);
        return (c < 16 ? '0' : '') + c.toString(16);
    }).join('');
}

function clamp(v, max) {
    return Math.min(Math.max(v, 0), max); 
}

})(require('../tree'));

(function (tree) {

tree.Comment = function (value, silent, index, currentFileInfo) {
    this.value = value;
    this.silent = !!silent;
    this.currentFileInfo = currentFileInfo;
};
tree.Comment.prototype = {
    type: "Comment",
    genCSS: function (env, output) {
        if (this.debugInfo) {
            output.add(tree.debugInfo(env, this), this.currentFileInfo, this.index);
        }
        output.add(this.value.trim()); //TODO shouldn't need to trim, we shouldn't grab the \n
    },
    toCSS: tree.toCSS,
    isSilent: function(env) {
        var isReference = (this.currentFileInfo && this.currentFileInfo.reference && !this.isReferenced),
            isCompressed = env.compress && !this.value.match(/^\/\*!/);
        return this.silent || isReference || isCompressed;
    },
    eval: function () { return this; },
    markReferenced: function () {
        this.isReferenced = true;
    }
};

})(require('../tree'));

(function (tree) {

tree.Condition = function (op, l, r, i, negate) {
    this.op = op.trim();
    this.lvalue = l;
    this.rvalue = r;
    this.index = i;
    this.negate = negate;
};
tree.Condition.prototype = {
    type: "Condition",
    accept: function (visitor) {
        this.lvalue = visitor.visit(this.lvalue);
        this.rvalue = visitor.visit(this.rvalue);
    },
    eval: function (env) {
        var a = this.lvalue.eval(env),
            b = this.rvalue.eval(env);

        var i = this.index, result;

        result = (function (op) {
            switch (op) {
                case 'and':
                    return a && b;
                case 'or':
                    return a || b;
                default:
                    if (a.compare) {
                        result = a.compare(b);
                    } else if (b.compare) {
                        result = b.compare(a);
                    } else {
                        throw { type: "Type",
                                message: "Unable to perform comparison",
                                index: i };
                    }
                    switch (result) {
                        case -1: return op === '<' || op === '=<' || op === '<=';
                        case  0: return op === '=' || op === '>=' || op === '=<' || op === '<=';
                        case  1: return op === '>' || op === '>=';
                    }
            }
        })(this.op);
        return this.negate ? !result : result;
    }
};

})(require('../tree'));

(function (tree) {

//
// A number with a unit
//
tree.Dimension = function (value, unit) {
    this.value = parseFloat(value);
    this.unit = (unit && unit instanceof tree.Unit) ? unit :
      new(tree.Unit)(unit ? [unit] : undefined);
};

tree.Dimension.prototype = {
    type: "Dimension",
    accept: function (visitor) {
        this.unit = visitor.visit(this.unit);
    },
    eval: function (env) {
        return this;
    },
    toColor: function () {
        return new(tree.Color)([this.value, this.value, this.value]);
    },
    genCSS: function (env, output) {
        if ((env && env.strictUnits) && !this.unit.isSingular()) {
            throw new Error("Multiple units in dimension. Correct the units or use the unit function. Bad unit: "+this.unit.toString());
        }

        var value = this.value,
            strValue = String(value);

        if (value !== 0 && value < 0.000001 && value > -0.000001) {
            // would be output 1e-6 etc.
            strValue = value.toFixed(20).replace(/0+$/, "");
        }

        if (env && env.compress) {
            // Zero values doesn't need a unit
            if (value === 0 && this.unit.isLength()) {
                output.add(strValue);
                return;
            }

            // Float values doesn't need a leading zero
            if (value > 0 && value < 1) {
                strValue = (strValue).substr(1);
            }
        }

        output.add(strValue);
        this.unit.genCSS(env, output);
    },
    toCSS: tree.toCSS,

    // In an operation between two Dimensions,
    // we default to the first Dimension's unit,
    // so `1px + 2` will yield `3px`.
    operate: function (env, op, other) {
        /*jshint noempty:false */
        var value = tree.operate(env, op, this.value, other.value),
            unit = this.unit.clone();

        if (op === '+' || op === '-') {
            if (unit.numerator.length === 0 && unit.denominator.length === 0) {
                unit.numerator = other.unit.numerator.slice(0);
                unit.denominator = other.unit.denominator.slice(0);
            } else if (other.unit.numerator.length === 0 && unit.denominator.length === 0) {
                // do nothing
            } else {
                other = other.convertTo(this.unit.usedUnits());

                if(env.strictUnits && other.unit.toString() !== unit.toString()) {
                  throw new Error("Incompatible units. Change the units or use the unit function. Bad units: '" + unit.toString() +
                    "' and '" + other.unit.toString() + "'.");
                }

                value = tree.operate(env, op, this.value, other.value);
            }
        } else if (op === '*') {
            unit.numerator = unit.numerator.concat(other.unit.numerator).sort();
            unit.denominator = unit.denominator.concat(other.unit.denominator).sort();
            unit.cancel();
        } else if (op === '/') {
            unit.numerator = unit.numerator.concat(other.unit.denominator).sort();
            unit.denominator = unit.denominator.concat(other.unit.numerator).sort();
            unit.cancel();
        }
        return new(tree.Dimension)(value, unit);
    },

    compare: function (other) {
        if (other instanceof tree.Dimension) {
            var a = this.unify(), b = other.unify(),
                aValue = a.value, bValue = b.value;

            if (bValue > aValue) {
                return -1;
            } else if (bValue < aValue) {
                return 1;
            } else {
                if (!b.unit.isEmpty() && a.unit.compare(b.unit) !== 0) {
                    return -1;
                }
                return 0;
            }
        } else {
            return -1;
        }
    },

    unify: function () {
        return this.convertTo({ length: 'm', duration: 's', angle: 'rad' });
    },

    convertTo: function (conversions) {
        var value = this.value, unit = this.unit.clone(),
            i, groupName, group, targetUnit, derivedConversions = {}, applyUnit;

        if (typeof conversions === 'string') {
            for(i in tree.UnitConversions) {
                if (tree.UnitConversions[i].hasOwnProperty(conversions)) {
                    derivedConversions = {};
                    derivedConversions[i] = conversions;
                }
            }
            conversions = derivedConversions;
        }
        applyUnit = function (atomicUnit, denominator) {
          /*jshint loopfunc:true */
            if (group.hasOwnProperty(atomicUnit)) {
                if (denominator) {
                    value = value / (group[atomicUnit] / group[targetUnit]);
                } else {
                    value = value * (group[atomicUnit] / group[targetUnit]);
                }

                return targetUnit;
            }

            return atomicUnit;
        };

        for (groupName in conversions) {
            if (conversions.hasOwnProperty(groupName)) {
                targetUnit = conversions[groupName];
                group = tree.UnitConversions[groupName];

                unit.map(applyUnit);
            }
        }

        unit.cancel();

        return new(tree.Dimension)(value, unit);
    }
};

// http://www.w3.org/TR/css3-values/#absolute-lengths
tree.UnitConversions = {
    length: {
         'm': 1,
        'cm': 0.01,
        'mm': 0.001,
        'in': 0.0254,
        'pt': 0.0254 / 72,
        'pc': 0.0254 / 72 * 12
    },
    duration: {
        's': 1,
        'ms': 0.001
    },
    angle: {
        'rad': 1/(2*Math.PI),
        'deg': 1/360,
        'grad': 1/400,
        'turn': 1
    }
};

tree.Unit = function (numerator, denominator, backupUnit) {
    this.numerator = numerator ? numerator.slice(0).sort() : [];
    this.denominator = denominator ? denominator.slice(0).sort() : [];
    this.backupUnit = backupUnit;
};

tree.Unit.prototype = {
    type: "Unit",
    clone: function () {
        return new tree.Unit(this.numerator.slice(0), this.denominator.slice(0), this.backupUnit);
    },
    genCSS: function (env, output) {
        if (this.numerator.length >= 1) {
            output.add(this.numerator[0]);
        } else
        if (this.denominator.length >= 1) {
            output.add(this.denominator[0]);
        } else
        if ((!env || !env.strictUnits) && this.backupUnit) {
            output.add(this.backupUnit);
        }
    },
    toCSS: tree.toCSS,

    toString: function () {
      var i, returnStr = this.numerator.join("*");
      for (i = 0; i < this.denominator.length; i++) {
          returnStr += "/" + this.denominator[i];
      }
      return returnStr;
    },

    compare: function (other) {
        return this.is(other.toString()) ? 0 : -1;
    },

    is: function (unitString) {
        return this.toString() === unitString;
    },

    isLength: function () {
        return Boolean(this.toCSS().match(/px|em|%|in|cm|mm|pc|pt|ex/));
    },

    isEmpty: function () {
        return this.numerator.length === 0 && this.denominator.length === 0;
    },

    isSingular: function() {
        return this.numerator.length <= 1 && this.denominator.length === 0;
    },

    map: function(callback) {
        var i;

        for (i = 0; i < this.numerator.length; i++) {
            this.numerator[i] = callback(this.numerator[i], false);
        }

        for (i = 0; i < this.denominator.length; i++) {
            this.denominator[i] = callback(this.denominator[i], true);
        }
    },

    usedUnits: function() {
        var group, result = {}, mapUnit;

        mapUnit = function (atomicUnit) {
        /*jshint loopfunc:true */
            if (group.hasOwnProperty(atomicUnit) && !result[groupName]) {
                result[groupName] = atomicUnit;
            }

            return atomicUnit;
        };

        for (var groupName in tree.UnitConversions) {
            if (tree.UnitConversions.hasOwnProperty(groupName)) {
                group = tree.UnitConversions[groupName];

                this.map(mapUnit);
            }
        }

        return result;
    },

    cancel: function () {
        var counter = {}, atomicUnit, i, backup;

        for (i = 0; i < this.numerator.length; i++) {
            atomicUnit = this.numerator[i];
            if (!backup) {
                backup = atomicUnit;
            }
            counter[atomicUnit] = (counter[atomicUnit] || 0) + 1;
        }

        for (i = 0; i < this.denominator.length; i++) {
            atomicUnit = this.denominator[i];
            if (!backup) {
                backup = atomicUnit;
            }
            counter[atomicUnit] = (counter[atomicUnit] || 0) - 1;
        }

        this.numerator = [];
        this.denominator = [];

        for (atomicUnit in counter) {
            if (counter.hasOwnProperty(atomicUnit)) {
                var count = counter[atomicUnit];

                if (count > 0) {
                    for (i = 0; i < count; i++) {
                        this.numerator.push(atomicUnit);
                    }
                } else if (count < 0) {
                    for (i = 0; i < -count; i++) {
                        this.denominator.push(atomicUnit);
                    }
                }
            }
        }

        if (this.numerator.length === 0 && this.denominator.length === 0 && backup) {
            this.backupUnit = backup;
        }

        this.numerator.sort();
        this.denominator.sort();
    }
};

})(require('../tree'));

(function (tree) {

tree.Directive = function (name, value, index, currentFileInfo) {
    this.name = name;

    if (Array.isArray(value)) {
        this.rules = [new(tree.Ruleset)(null, value)];
        this.rules[0].allowImports = true;
    } else {
        this.value = value;
    }
    this.currentFileInfo = currentFileInfo;

};
tree.Directive.prototype = {
    type: "Directive",
    accept: function (visitor) {
        if (this.rules) {
            this.rules = visitor.visitArray(this.rules);
        }
        if (this.value) {
            this.value = visitor.visit(this.value);
        }
    },
    genCSS: function (env, output) {
        output.add(this.name, this.currentFileInfo, this.index);
        if (this.rules) {
            tree.outputRuleset(env, output, this.rules);
        } else {
            output.add(' ');
            this.value.genCSS(env, output);
            output.add(';');
        }
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        var evaldDirective = this;
        if (this.rules) {
            env.frames.unshift(this);
            evaldDirective = new(tree.Directive)(this.name, null, this.index, this.currentFileInfo);
            evaldDirective.rules = [this.rules[0].eval(env)];
            evaldDirective.rules[0].root = true;
            env.frames.shift();
        }
        return evaldDirective;
    },
    variable: function (name) { return tree.Ruleset.prototype.variable.call(this.rules[0], name); },
    find: function () { return tree.Ruleset.prototype.find.apply(this.rules[0], arguments); },
    rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.rules[0]); },
    markReferenced: function () {
        var i, rules;
        this.isReferenced = true;
        if (this.rules) {
            rules = this.rules[0].rules;
            for (i = 0; i < rules.length; i++) {
                if (rules[i].markReferenced) {
                    rules[i].markReferenced();
                }
            }
        }
    }
};

})(require('../tree'));

(function (tree) {

tree.Element = function (combinator, value, index, currentFileInfo) {
    this.combinator = combinator instanceof tree.Combinator ?
                      combinator : new(tree.Combinator)(combinator);

    if (typeof(value) === 'string') {
        this.value = value.trim();
    } else if (value) {
        this.value = value;
    } else {
        this.value = "";
    }
    this.index = index;
    this.currentFileInfo = currentFileInfo;
};
tree.Element.prototype = {
    type: "Element",
    accept: function (visitor) {
        var value = this.value;
        this.combinator = visitor.visit(this.combinator);
        if (typeof value === "object") {
            this.value = visitor.visit(value);
        }
    },
    eval: function (env) {
        return new(tree.Element)(this.combinator,
                                 this.value.eval ? this.value.eval(env) : this.value,
                                 this.index,
                                 this.currentFileInfo);
    },
    genCSS: function (env, output) {
        output.add(this.toCSS(env), this.currentFileInfo, this.index);
    },
    toCSS: function (env) {
        var value = (this.value.toCSS ? this.value.toCSS(env) : this.value);
        if (value === '' && this.combinator.value.charAt(0) === '&') {
            return '';
        } else {
            return this.combinator.toCSS(env || {}) + value;
        }
    }
};

tree.Attribute = function (key, op, value) {
    this.key = key;
    this.op = op;
    this.value = value;
};
tree.Attribute.prototype = {
    type: "Attribute",
    eval: function (env) {
        return new(tree.Attribute)(this.key.eval ? this.key.eval(env) : this.key,
            this.op, (this.value && this.value.eval) ? this.value.eval(env) : this.value);
    },
    genCSS: function (env, output) {
        output.add(this.toCSS(env));
    },
    toCSS: function (env) {
        var value = this.key.toCSS ? this.key.toCSS(env) : this.key;

        if (this.op) {
            value += this.op;
            value += (this.value.toCSS ? this.value.toCSS(env) : this.value);
        }

        return '[' + value + ']';
    }
};

tree.Combinator = function (value) {
    if (value === ' ') {
        this.value = ' ';
    } else {
        this.value = value ? value.trim() : "";
    }
};
tree.Combinator.prototype = {
    type: "Combinator",
    _outputMap: {
        ''  : '',
        ' ' : ' ',
        ':' : ' :',
        '+' : ' + ',
        '~' : ' ~ ',
        '>' : ' > ',
        '|' : '|'
    },
    _outputMapCompressed: {
        ''  : '',
        ' ' : ' ',
        ':' : ' :',
        '+' : '+',
        '~' : '~',
        '>' : '>',
        '|' : '|'
    },
    genCSS: function (env, output) {
        output.add((env.compress ? this._outputMapCompressed : this._outputMap)[this.value]);
    },
    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {

tree.Expression = function (value) { this.value = value; };
tree.Expression.prototype = {
    type: "Expression",
    accept: function (visitor) {
        if (this.value) {
            this.value = visitor.visitArray(this.value);
        }
    },
    eval: function (env) {
        var returnValue,
            inParenthesis = this.parens && !this.parensInOp,
            doubleParen = false;
        if (inParenthesis) {
            env.inParenthesis();
        }
        if (this.value.length > 1) {
            returnValue = new(tree.Expression)(this.value.map(function (e) {
                return e.eval(env);
            }));
        } else if (this.value.length === 1) {
            if (this.value[0].parens && !this.value[0].parensInOp) {
                doubleParen = true;
            }
            returnValue = this.value[0].eval(env);
        } else {
            returnValue = this;
        }
        if (inParenthesis) {
            env.outOfParenthesis();
        }
        if (this.parens && this.parensInOp && !(env.isMathOn()) && !doubleParen) {
            returnValue = new(tree.Paren)(returnValue);
        }
        return returnValue;
    },
    genCSS: function (env, output) {
        for(var i = 0; i < this.value.length; i++) {
            this.value[i].genCSS(env, output);
            if (i + 1 < this.value.length) {
                output.add(" ");
            }
        }
    },
    toCSS: tree.toCSS,
    throwAwayComments: function () {
        this.value = this.value.filter(function(v) {
            return !(v instanceof tree.Comment);
        });
    }
};

})(require('../tree'));

(function (tree) {

tree.Extend = function Extend(selector, option, index) {
    this.selector = selector;
    this.option = option;
    this.index = index;
    this.object_id = tree.Extend.next_id++;
    this.parent_ids = [this.object_id];

    switch(option) {
        case "all":
            this.allowBefore = true;
            this.allowAfter = true;
        break;
        default:
            this.allowBefore = false;
            this.allowAfter = false;
        break;
    }
};
tree.Extend.next_id = 0;

tree.Extend.prototype = {
    type: "Extend",
    accept: function (visitor) {
        this.selector = visitor.visit(this.selector);
    },
    eval: function (env) {
        return new(tree.Extend)(this.selector.eval(env), this.option, this.index);
    },
    clone: function (env) {
        return new(tree.Extend)(this.selector, this.option, this.index);
    },
    findSelfSelectors: function (selectors) {
        var selfElements = [],
            i,
            selectorElements;

        for(i = 0; i < selectors.length; i++) {
            selectorElements = selectors[i].elements;
            // duplicate the logic in genCSS function inside the selector node.
            // future TODO - move both logics into the selector joiner visitor
            if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === "") {
                selectorElements[0].combinator.value = ' ';
            }
            selfElements = selfElements.concat(selectors[i].elements);
        }

        this.selfSelectors = [{ elements: selfElements }];
    }
};

})(require('../tree'));

(function (tree) {
//
// CSS @import node
//
// The general strategy here is that we don't want to wait
// for the parsing to be completed, before we start importing
// the file. That's because in the context of a browser,
// most of the time will be spent waiting for the server to respond.
//
// On creation, we push the import path to our import queue, though
// `import,push`, we also pass it a callback, which it'll call once
// the file has been fetched, and parsed.
//
tree.Import = function (path, features, options, index, currentFileInfo) {
    this.options = options;
    this.index = index;
    this.path = path;
    this.features = features;
    this.currentFileInfo = currentFileInfo;

    if (this.options.less !== undefined || this.options.inline) {
        this.css = !this.options.less || this.options.inline;
    } else {
        var pathValue = this.getPath();
        if (pathValue && /css([\?;].*)?$/.test(pathValue)) {
            this.css = true;
        }
    }
};

//
// The actual import node doesn't return anything, when converted to CSS.
// The reason is that it's used at the evaluation stage, so that the rules
// it imports can be treated like any other rules.
//
// In `eval`, we make sure all Import nodes get evaluated, recursively, so
// we end up with a flat structure, which can easily be imported in the parent
// ruleset.
//
tree.Import.prototype = {
    type: "Import",
    accept: function (visitor) {
        if (this.features) {
            this.features = visitor.visit(this.features);
        }
        this.path = visitor.visit(this.path);
        if (!this.options.inline && this.root) {
            this.root = visitor.visit(this.root);
        }
    },
    genCSS: function (env, output) {
        if (this.css) {
            output.add("@import ", this.currentFileInfo, this.index);
            this.path.genCSS(env, output);
            if (this.features) {
                output.add(" ");
                this.features.genCSS(env, output);
            }
            output.add(';');
        }
    },
    toCSS: tree.toCSS,
    getPath: function () {
        if (this.path instanceof tree.Quoted) {
            var path = this.path.value;
            return (this.css !== undefined || /(\.[a-z]*$)|([\?;].*)$/.test(path)) ? path : path + '.less';
        } else if (this.path instanceof tree.URL) {
            return this.path.value.value;
        }
        return null;
    },
    evalForImport: function (env) {
        return new(tree.Import)(this.path.eval(env), this.features, this.options, this.index, this.currentFileInfo);
    },
    evalPath: function (env) {
        var path = this.path.eval(env);
        var rootpath = this.currentFileInfo && this.currentFileInfo.rootpath;

        if (!(path instanceof tree.URL)) {
            if (rootpath) {
                var pathValue = path.value;
                // Add the base path if the import is relative
                if (pathValue && env.isPathRelative(pathValue)) {
                    path.value = rootpath + pathValue;
                }
            }
            path.value = env.normalizePath(path.value);
        }

        return path;
    },
    eval: function (env) {
        var ruleset, features = this.features && this.features.eval(env);

        if (this.skip) { return []; }

        if (this.options.inline) {
            //todo needs to reference css file not import
            var contents = new(tree.Anonymous)(this.root, 0, {filename: this.importedFilename}, true);
            return this.features ? new(tree.Media)([contents], this.features.value) : [contents];
        } else if (this.css) {
            var newImport = new(tree.Import)(this.evalPath(env), features, this.options, this.index);
            if (!newImport.css && this.error) {
                throw this.error;
            }
            return newImport;
        } else {
            ruleset = new(tree.Ruleset)(null, this.root.rules.slice(0));

            ruleset.evalImports(env);

            return this.features ? new(tree.Media)(ruleset.rules, this.features.value) : ruleset.rules;
        }
    }
};

})(require('../tree'));

(function (tree) {

tree.JavaScript = function (string, index, escaped) {
    this.escaped = escaped;
    this.expression = string;
    this.index = index;
};
tree.JavaScript.prototype = {
    type: "JavaScript",
    eval: function (env) {
        var result,
            that = this,
            context = {};

        var expression = this.expression.replace(/@\{([\w-]+)\}/g, function (_, name) {
            return tree.jsify(new(tree.Variable)('@' + name, that.index).eval(env));
        });

        try {
            expression = new(Function)('return (' + expression + ')');
        } catch (e) {
            throw { message: "JavaScript evaluation error: " + e.message + " from `" + expression + "`" ,
                    index: this.index };
        }

        for (var k in env.frames[0].variables()) {
            /*jshint loopfunc:true */
            context[k.slice(1)] = {
                value: env.frames[0].variables()[k].value,
                toJS: function () {
                    return this.value.eval(env).toCSS();
                }
            };
        }

        try {
            result = expression.call(context);
        } catch (e) {
            throw { message: "JavaScript evaluation error: '" + e.name + ': ' + e.message + "'" ,
                    index: this.index };
        }
        if (typeof(result) === 'number') {
            return new(tree.Dimension)(result);
        } else if (typeof(result) === 'string') {
            return new(tree.Quoted)('"' + result + '"', result, this.escaped, this.index);
        } else if (Array.isArray(result)) {
            return new(tree.Anonymous)(result.join(', '));
        } else {
            return new(tree.Anonymous)(result);
        }
    }
};

})(require('../tree'));


(function (tree) {

tree.Keyword = function (value) { this.value = value; };
tree.Keyword.prototype = {
    type: "Keyword",
    eval: function () { return this; },
    genCSS: function (env, output) {
        output.add(this.value);
    },
    toCSS: tree.toCSS,
    compare: function (other) {
        if (other instanceof tree.Keyword) {
            return other.value === this.value ? 0 : 1;
        } else {
            return -1;
        }
    }
};

tree.True = new(tree.Keyword)('true');
tree.False = new(tree.Keyword)('false');

})(require('../tree'));

(function (tree) {

tree.Media = function (value, features, index, currentFileInfo) {
    this.index = index;
    this.currentFileInfo = currentFileInfo;

    var selectors = this.emptySelectors();

    this.features = new(tree.Value)(features);
    this.rules = [new(tree.Ruleset)(selectors, value)];
    this.rules[0].allowImports = true;
};
tree.Media.prototype = {
    type: "Media",
    accept: function (visitor) {
        if (this.features) {
            this.features = visitor.visit(this.features);
        }
        if (this.rules) {
            this.rules = visitor.visitArray(this.rules);
        }
    },
    genCSS: function (env, output) {
        output.add('@media ', this.currentFileInfo, this.index);
        this.features.genCSS(env, output);
        tree.outputRuleset(env, output, this.rules);
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        if (!env.mediaBlocks) {
            env.mediaBlocks = [];
            env.mediaPath = [];
        }
        
        var media = new(tree.Media)(null, [], this.index, this.currentFileInfo);
        if(this.debugInfo) {
            this.rules[0].debugInfo = this.debugInfo;
            media.debugInfo = this.debugInfo;
        }
        var strictMathBypass = false;
        if (!env.strictMath) {
            strictMathBypass = true;
            env.strictMath = true;
        }
        try {
            media.features = this.features.eval(env);
        }
        finally {
            if (strictMathBypass) {
                env.strictMath = false;
            }
        }
        
        env.mediaPath.push(media);
        env.mediaBlocks.push(media);
        
        env.frames.unshift(this.rules[0]);
        media.rules = [this.rules[0].eval(env)];
        env.frames.shift();
        
        env.mediaPath.pop();

        return env.mediaPath.length === 0 ? media.evalTop(env) :
                    media.evalNested(env);
    },
    variable: function (name) { return tree.Ruleset.prototype.variable.call(this.rules[0], name); },
    find: function () { return tree.Ruleset.prototype.find.apply(this.rules[0], arguments); },
    rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.rules[0]); },
    emptySelectors: function() { 
        var el = new(tree.Element)('', '&', this.index, this.currentFileInfo);
        return [new(tree.Selector)([el], null, null, this.index, this.currentFileInfo)];
    },
    markReferenced: function () {
        var i, rules = this.rules[0].rules;
        this.isReferenced = true;
        for (i = 0; i < rules.length; i++) {
            if (rules[i].markReferenced) {
                rules[i].markReferenced();
            }
        }
    },

    evalTop: function (env) {
        var result = this;

        // Render all dependent Media blocks.
        if (env.mediaBlocks.length > 1) {
            var selectors = this.emptySelectors();
            result = new(tree.Ruleset)(selectors, env.mediaBlocks);
            result.multiMedia = true;
        }

        delete env.mediaBlocks;
        delete env.mediaPath;

        return result;
    },
    evalNested: function (env) {
        var i, value,
            path = env.mediaPath.concat([this]);

        // Extract the media-query conditions separated with `,` (OR).
        for (i = 0; i < path.length; i++) {
            value = path[i].features instanceof tree.Value ?
                        path[i].features.value : path[i].features;
            path[i] = Array.isArray(value) ? value : [value];
        }

        // Trace all permutations to generate the resulting media-query.
        //
        // (a, b and c) with nested (d, e) ->
        //    a and d
        //    a and e
        //    b and c and d
        //    b and c and e
        this.features = new(tree.Value)(this.permute(path).map(function (path) {
            path = path.map(function (fragment) {
                return fragment.toCSS ? fragment : new(tree.Anonymous)(fragment);
            });

            for(i = path.length - 1; i > 0; i--) {
                path.splice(i, 0, new(tree.Anonymous)("and"));
            }

            return new(tree.Expression)(path);
        }));

        // Fake a tree-node that doesn't output anything.
        return new(tree.Ruleset)([], []);
    },
    permute: function (arr) {
      if (arr.length === 0) {
          return [];
      } else if (arr.length === 1) {
          return arr[0];
      } else {
          var result = [];
          var rest = this.permute(arr.slice(1));
          for (var i = 0; i < rest.length; i++) {
              for (var j = 0; j < arr[0].length; j++) {
                  result.push([arr[0][j]].concat(rest[i]));
              }
          }
          return result;
      }
    },
    bubbleSelectors: function (selectors) {
      this.rules = [new(tree.Ruleset)(selectors.slice(0), [this.rules[0]])];
    }
};

})(require('../tree'));

(function (tree) {

tree.mixin = {};
tree.mixin.Call = function (elements, args, index, currentFileInfo, important) {
    this.selector = new(tree.Selector)(elements);
    this.arguments = (args && args.length) ? args : null;
    this.index = index;
    this.currentFileInfo = currentFileInfo;
    this.important = important;
};
tree.mixin.Call.prototype = {
    type: "MixinCall",
    accept: function (visitor) {
        if (this.selector) {
            this.selector = visitor.visit(this.selector);
        }
        if (this.arguments) {
            this.arguments = visitor.visitArray(this.arguments);
        }
    },
    eval: function (env) {
        var mixins, mixin, args, rules = [], match = false, i, m, f, isRecursive, isOneFound, rule;
        var candidates = [], candidate, conditionResult = [], defaultFunc = tree.defaultFunc, defaultUsed = false; 

        args = this.arguments && this.arguments.map(function (a) {
            return { name: a.name, value: a.value.eval(env) };
        });

        for (i = 0; i < env.frames.length; i++) {
            if ((mixins = env.frames[i].find(this.selector)).length > 0) {
                isOneFound = true;
                
                // To make `default()` function independent of definition order we have two "subpasses" here.
                // At first we evaluate each guard *twice* (with `default() == true` and `default() == false`),
                // and build candidate list with corresponding flags. Then, when we know all possible matches,
                // we make a final decision.
                
                for (m = 0; m < mixins.length; m++) {
                    mixin = mixins[m];
                    isRecursive = false;
                    for(f = 0; f < env.frames.length; f++) {
                        if ((!(mixin instanceof tree.mixin.Definition)) && mixin === (env.frames[f].originalRuleset || env.frames[f])) {
                            isRecursive = true;
                            break;
                        }
                    }
                    if (isRecursive) {
                        continue;
                    }
                    
                    if (mixin.matchArgs(args, env)) {  
                        candidate = {mixin: mixin};
                        
                        if (mixin.matchCondition) { 
                            for (f = 0; f < 2; f++) {
                                defaultFunc.value(f);
                                conditionResult[f] = mixin.matchCondition(args, env);
                            }
                            if (conditionResult[0] || conditionResult[1]) {
                                if (conditionResult[0] != conditionResult[1]) {
                                    if (defaultUsed) {
                                        // todo: ideally, it would make sense to also print the candidate 
                                        // mixin definitions that cause the conflict (current one and the
                                        // mixin that set defaultUsed flag). But is there any easy method 
                                        // to get their filename/line/index info here?
                                        throw { type: 'Runtime',
                                            message: 'Ambiguous use of `default()` found when matching for `'
                                                + this.format(args) + '`',
                                            index: this.index, filename: this.currentFileInfo.filename };
                                    }
                                    
                                    defaultUsed                   = true;
                                    candidate.matchIfDefault      = true;
                                    candidate.matchIfDefaultValue = conditionResult[1];
                                }

                                candidates.push(candidate);
                            }   
                        }
                        else {
                            candidates.push(candidate);
                        }
                        
                        match = true;
                    }
                }
                
                defaultFunc.reset();
                
                for (m in candidates) {
                    candidate = candidates[m];
                    if (!candidate.matchIfDefault || (candidate.matchIfDefaultValue == (candidates.length == 1))) {
                        try {
                            mixin = candidate.mixin;
                            if (!(mixin instanceof tree.mixin.Definition)) {
                                mixin = new tree.mixin.Definition("", [], mixin.rules, null, false);
                                mixin.originalRuleset = mixins[m].originalRuleset || mixins[m];
                            }
                            //if (this.important) {
                            //    isImportant = env.isImportant;
                            //    env.isImportant = true;
                            //}
                            Array.prototype.push.apply(
                                  rules, mixin.eval(env, args, this.important).rules);
                            //if (this.important) {
                            //    env.isImportant = isImportant;
                            //}
                        } catch (e) {
                            throw { message: e.message, index: this.index, filename: this.currentFileInfo.filename, stack: e.stack };
                        }
                    }
                }
                
                if (match) {
                    if (!this.currentFileInfo || !this.currentFileInfo.reference) {
                        for (i = 0; i < rules.length; i++) {
                            rule = rules[i];
                            if (rule.markReferenced) {
                                rule.markReferenced();
                            }
                        }
                    }
                    return rules;
                }
            }
        }
        if (isOneFound) {
            throw { type:    'Runtime',
                    message: 'No matching definition was found for `' + this.format(args) + '`',
                    index:   this.index, filename: this.currentFileInfo.filename };
        } else {
            throw { type:    'Name',
                    message: this.selector.toCSS().trim() + " is undefined",
                    index:   this.index, filename: this.currentFileInfo.filename };
        }
    },
    format: function (args) {
        return this.selector.toCSS().trim() + '(' +
            (args ? args.map(function (a) {
                var argValue = "";
                if (a.name) {
                    argValue += a.name + ":";
                }
                if (a.value.toCSS) {
                    argValue += a.value.toCSS();
                } else {
                    argValue += "???";
                }
                return argValue;
            }).join(', ') : "") + ")";
    }
};

tree.mixin.Definition = function (name, params, rules, condition, variadic) {
    this.name = name;
    this.selectors = [new(tree.Selector)([new(tree.Element)(null, name, this.index, this.currentFileInfo)])];
    this.params = params;
    this.condition = condition;
    this.variadic = variadic;
    this.arity = params.length;
    this.rules = rules;
    this._lookups = {};
    this.required = params.reduce(function (count, p) {
        if (!p.name || (p.name && !p.value)) { return count + 1; }
        else                                 { return count; }
    }, 0);
    this.parent = tree.Ruleset.prototype;
    this.frames = [];
};
tree.mixin.Definition.prototype = {
    type: "MixinDefinition",
    accept: function (visitor) {
        if (this.params && this.params.length) {
            this.params = visitor.visitArray(this.params);
        }
        this.rules = visitor.visitArray(this.rules);
        if (this.condition) {
            this.condition = visitor.visit(this.condition);
        }
    },
    variable:  function (name) { return this.parent.variable.call(this, name); },
    variables: function ()     { return this.parent.variables.call(this); },
    find:      function ()     { return this.parent.find.apply(this, arguments); },
    rulesets:  function ()     { return this.parent.rulesets.apply(this); },

    evalParams: function (env, mixinEnv, args, evaldArguments) {
        /*jshint boss:true */
        var frame = new(tree.Ruleset)(null, null),
            varargs, arg,
            params = this.params.slice(0),
            i, j, val, name, isNamedFound, argIndex;

        mixinEnv = new tree.evalEnv(mixinEnv, [frame].concat(mixinEnv.frames));

        if (args) {
            args = args.slice(0);

            for(i = 0; i < args.length; i++) {
                arg = args[i];
                if (name = (arg && arg.name)) {
                    isNamedFound = false;
                    for(j = 0; j < params.length; j++) {
                        if (!evaldArguments[j] && name === params[j].name) {
                            evaldArguments[j] = arg.value.eval(env);
                            frame.prependRule(new(tree.Rule)(name, arg.value.eval(env)));
                            isNamedFound = true;
                            break;
                        }
                    }
                    if (isNamedFound) {
                        args.splice(i, 1);
                        i--;
                        continue;
                    } else {
                        throw { type: 'Runtime', message: "Named argument for " + this.name +
                            ' ' + args[i].name + ' not found' };
                    }
                }
            }
        }
        argIndex = 0;
        for (i = 0; i < params.length; i++) {
            if (evaldArguments[i]) { continue; }

            arg = args && args[argIndex];

            if (name = params[i].name) {
                if (params[i].variadic && args) {
                    varargs = [];
                    for (j = argIndex; j < args.length; j++) {
                        varargs.push(args[j].value.eval(env));
                    }
                    frame.prependRule(new(tree.Rule)(name, new(tree.Expression)(varargs).eval(env)));
                } else {
                    val = arg && arg.value;
                    if (val) {
                        val = val.eval(env);
                    } else if (params[i].value) {
                        val = params[i].value.eval(mixinEnv);
                        frame.resetCache();
                    } else {
                        throw { type: 'Runtime', message: "wrong number of arguments for " + this.name +
                            ' (' + args.length + ' for ' + this.arity + ')' };
                    }
                    
                    frame.prependRule(new(tree.Rule)(name, val));
                    evaldArguments[i] = val;
                }
            }

            if (params[i].variadic && args) {
                for (j = argIndex; j < args.length; j++) {
                    evaldArguments[j] = args[j].value.eval(env);
                }
            }
            argIndex++;
        }

        return frame;
    },
    eval: function (env, args, important) {
        var _arguments = [],
            mixinFrames = this.frames.concat(env.frames),
            frame = this.evalParams(env, new(tree.evalEnv)(env, mixinFrames), args, _arguments),
            rules, ruleset;

        frame.prependRule(new(tree.Rule)('@arguments', new(tree.Expression)(_arguments).eval(env)));

        rules = this.rules.slice(0);

        ruleset = new(tree.Ruleset)(null, rules);
        ruleset.originalRuleset = this;
        ruleset = ruleset.eval(new(tree.evalEnv)(env, [this, frame].concat(mixinFrames)));
        if (important) {
            ruleset = this.parent.makeImportant.apply(ruleset);
        }
        return ruleset;
    },
    matchCondition: function (args, env) {
        if (this.condition && !this.condition.eval(
            new(tree.evalEnv)(env,
                [this.evalParams(env, new(tree.evalEnv)(env, this.frames.concat(env.frames)), args, [])] // the parameter variables
                    .concat(this.frames) // the parent namespace/mixin frames
                    .concat(env.frames)))) { // the current environment frames
            return false;
        }
        return true;
    },
    matchArgs: function (args, env) {
        var argsLength = (args && args.length) || 0, len;

        if (! this.variadic) {
            if (argsLength < this.required)                               { return false; }
            if (argsLength > this.params.length)                          { return false; }
        } else {
            if (argsLength < (this.required - 1))                         { return false; }
        }

        len = Math.min(argsLength, this.arity);

        for (var i = 0; i < len; i++) {
            if (!this.params[i].name && !this.params[i].variadic) {
                if (args[i].value.eval(env).toCSS() != this.params[i].value.eval(env).toCSS()) {
                    return false;
                }
            }
        }
        return true;
    }
};

})(require('../tree'));

(function (tree) {

tree.Negative = function (node) {
    this.value = node;
};
tree.Negative.prototype = {
    type: "Negative",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    genCSS: function (env, output) {
        output.add('-');
        this.value.genCSS(env, output);
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        if (env.isMathOn()) {
            return (new(tree.Operation)('*', [new(tree.Dimension)(-1), this.value])).eval(env);
        }
        return new(tree.Negative)(this.value.eval(env));
    }
};

})(require('../tree'));

(function (tree) {

tree.Operation = function (op, operands, isSpaced) {
    this.op = op.trim();
    this.operands = operands;
    this.isSpaced = isSpaced;
};
tree.Operation.prototype = {
    type: "Operation",
    accept: function (visitor) {
        this.operands = visitor.visit(this.operands);
    },
    eval: function (env) {
        var a = this.operands[0].eval(env),
            b = this.operands[1].eval(env);

        if (env.isMathOn()) {
            if (a instanceof tree.Dimension && b instanceof tree.Color) {
                a = a.toColor();
            }
            if (b instanceof tree.Dimension && a instanceof tree.Color) {
                b = b.toColor();
            }
            if (!a.operate) {
                throw { type: "Operation",
                        message: "Operation on an invalid type" };
            }

            return a.operate(env, this.op, b);
        } else {
            return new(tree.Operation)(this.op, [a, b], this.isSpaced);
        }
    },
    genCSS: function (env, output) {
        this.operands[0].genCSS(env, output);
        if (this.isSpaced) {
            output.add(" ");
        }
        output.add(this.op);
        if (this.isSpaced) {
            output.add(" ");
        }
        this.operands[1].genCSS(env, output);
    },
    toCSS: tree.toCSS
};

tree.operate = function (env, op, a, b) {
    switch (op) {
        case '+': return a + b;
        case '-': return a - b;
        case '*': return a * b;
        case '/': return a / b;
    }
};

})(require('../tree'));


(function (tree) {

tree.Paren = function (node) {
    this.value = node;
};
tree.Paren.prototype = {
    type: "Paren",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    genCSS: function (env, output) {
        output.add('(');
        this.value.genCSS(env, output);
        output.add(')');
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        return new(tree.Paren)(this.value.eval(env));
    }
};

})(require('../tree'));

(function (tree) {

tree.Quoted = function (str, content, escaped, index, currentFileInfo) {
    this.escaped = escaped;
    this.value = content || '';
    this.quote = str.charAt(0);
    this.index = index;
    this.currentFileInfo = currentFileInfo;
};
tree.Quoted.prototype = {
    type: "Quoted",
    genCSS: function (env, output) {
        if (!this.escaped) {
            output.add(this.quote, this.currentFileInfo, this.index);
        }
        output.add(this.value);
        if (!this.escaped) {
            output.add(this.quote);
        }
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        var that = this;
        var value = this.value.replace(/`([^`]+)`/g, function (_, exp) {
            return new(tree.JavaScript)(exp, that.index, true).eval(env).value;
        }).replace(/@\{([\w-]+)\}/g, function (_, name) {
            var v = new(tree.Variable)('@' + name, that.index, that.currentFileInfo).eval(env, true);
            return (v instanceof tree.Quoted) ? v.value : v.toCSS();
        });
        return new(tree.Quoted)(this.quote + value + this.quote, value, this.escaped, this.index, this.currentFileInfo);
    },
    compare: function (x) {
        if (!x.toCSS) {
            return -1;
        }
        
        var left = this.toCSS(),
            right = x.toCSS();
        
        if (left === right) {
            return 0;
        }
        
        return left < right ? -1 : 1;
    }
};

})(require('../tree'));

(function (tree) {

tree.Rule = function (name, value, important, merge, index, currentFileInfo, inline) {
    this.name = name;
    this.value = (value instanceof tree.Value) ? value : new(tree.Value)([value]);
    this.important = important ? ' ' + important.trim() : '';
    this.merge = merge;
    this.index = index;
    this.currentFileInfo = currentFileInfo;
    this.inline = inline || false;
    this.variable = name.charAt && (name.charAt(0) === '@');
};

tree.Rule.prototype = {
    type: "Rule",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    genCSS: function (env, output) {
        output.add(this.name + (env.compress ? ':' : ': '), this.currentFileInfo, this.index);
        try {
            this.value.genCSS(env, output);
        }
        catch(e) {
            e.index = this.index;
            e.filename = this.currentFileInfo.filename;
            throw e;
        }
        output.add(this.important + ((this.inline || (env.lastRule && env.compress)) ? "" : ";"), this.currentFileInfo, this.index);
    },
    toCSS: tree.toCSS,
    eval: function (env) {
        var strictMathBypass = false;
        var name = this.name.map ? 
            this.name.map( function(v) {
                return v.eval ? v.eval(env).value : v;
            }).join('') : this.name;
        if (name === "font" && !env.strictMath) {
            strictMathBypass = true;
            env.strictMath = true;
        }
        try {
            return new(tree.Rule)(name,
                              this.value.eval(env),
                              this.important,
                              this.merge,
                              this.index, this.currentFileInfo, this.inline);
        }
        catch(e) {
            if (e.index === undefined) {
                e.index = this.index;
            }
            throw e;
        }
        finally {
            if (strictMathBypass) {
                env.strictMath = false;
            }
        }
    },
    makeImportant: function () {
        return new(tree.Rule)(this.name,
                              this.value,
                              "!important",
                              this.merge,
                              this.index, this.currentFileInfo, this.inline);
    }
};

})(require('../tree'));

(function (tree) {

tree.Ruleset = function (selectors, rules, strictImports) {
    this.selectors = selectors;
    this.rules = rules;
    this._lookups = {};
    this.strictImports = strictImports;
};
tree.Ruleset.prototype = {
    type: "Ruleset",
    accept: function (visitor) {
        if (this.paths) {
            visitor.visitArray(this.paths, true);
        } else if (this.selectors) {
            this.selectors = visitor.visitArray(this.selectors);
        }
        if (this.rules && this.rules.length) {
            this.rules = visitor.visitArray(this.rules);
        }
    },
    eval: function (env) {
        var thisSelectors = this.selectors, selectors, 
            selCnt, i, defaultFunc = tree.defaultFunc;
        if (thisSelectors && (selCnt = thisSelectors.length)) {
            selectors = [];
            defaultFunc.error({
                type: "Syntax", 
                message: "it is currently only allowed in parametric mixin guards," 
            });
            for (i = 0; i < selCnt; i++) {
                selectors.push(thisSelectors[i].eval(env));
            }
            defaultFunc.reset();  
        }

        var rules = this.rules ? this.rules.slice(0) : null,
            ruleset = new(tree.Ruleset)(selectors, rules, this.strictImports),
            rule;

        ruleset.originalRuleset = this;
        ruleset.root = this.root;
        ruleset.firstRoot = this.firstRoot;
        ruleset.allowImports = this.allowImports;

        if(this.debugInfo) {
            ruleset.debugInfo = this.debugInfo;
        }

        // push the current ruleset to the frames stack
        var envFrames = env.frames;
        envFrames.unshift(ruleset);

        // currrent selectors
        var envSelectors = env.selectors;
        if (!envSelectors) {
            env.selectors = envSelectors = [];
        }
        envSelectors.unshift(this.selectors);

        // Evaluate imports
        if (ruleset.root || ruleset.allowImports || !ruleset.strictImports) {
            ruleset.evalImports(env);
        }

        // Store the frames around mixin definitions,
        // so they can be evaluated like closures when the time comes.
        var rsRules = ruleset.rules, rsRuleCnt = rsRules ? rsRules.length : 0;
        for (i = 0; i < rsRuleCnt; i++) {
            if (rsRules[i] instanceof tree.mixin.Definition) {
                rsRules[i].frames = envFrames.slice(0);
            }
        }

        var mediaBlockCount = (env.mediaBlocks && env.mediaBlocks.length) || 0;

        // Evaluate mixin calls.
        for (i = 0; i < rsRuleCnt; i++) {
            if (rsRules[i] instanceof tree.mixin.Call) {
                /*jshint loopfunc:true */
                rules = rsRules[i].eval(env).filter(function(r) {
                    if ((r instanceof tree.Rule) && r.variable) {
                        // do not pollute the scope if the variable is
                        // already there. consider returning false here
                        // but we need a way to "return" variable from mixins
                        return !(ruleset.variable(r.name));
                    }
                    return true;
                });
                rsRules.splice.apply(rsRules, [i, 1].concat(rules));
                rsRuleCnt += rules.length - 1;
                i += rules.length-1;
                ruleset.resetCache();
            }
        }

        // Evaluate everything else
        for (i = 0; i < rsRuleCnt; i++) {
            rule = rsRules[i];
            if (! (rule instanceof tree.mixin.Definition)) {
                rsRules[i] = rule.eval ? rule.eval(env) : rule;
            }
        }

        // Pop the stack
        envFrames.shift();
        envSelectors.shift();
        
        if (env.mediaBlocks) {
            for (i = mediaBlockCount; i < env.mediaBlocks.length; i++) {
                env.mediaBlocks[i].bubbleSelectors(selectors);
            }
        }

        return ruleset;
    },
    evalImports: function(env) {
        var rules = this.rules, i, importRules;
        if (!rules) { return; }

        for (i = 0; i < rules.length; i++) {
            if (rules[i] instanceof tree.Import) {
                importRules = rules[i].eval(env);
                if (importRules && importRules.length) {
                    rules.splice.apply(rules, [i, 1].concat(importRules));
                    i+= importRules.length-1;
                } else {
                    rules.splice(i, 1, importRules);
                }
                this.resetCache();
            }
        }
    },
    makeImportant: function() {
        return new tree.Ruleset(this.selectors, this.rules.map(function (r) {
                    if (r.makeImportant) {
                        return r.makeImportant();
                    } else {
                        return r;
                    }
                }), this.strictImports);
    },
    matchArgs: function (args) {
        return !args || args.length === 0;
    },
    matchCondition: function (args, env) {
        var lastSelector = this.selectors[this.selectors.length-1];
        if (lastSelector.condition &&
            !lastSelector.condition.eval(
                new(tree.evalEnv)(env,
                    env.frames))) {
            return false;
        }
        return true;
    },
    resetCache: function () {
        this._rulesets = null;
        this._variables = null;
        this._lookups = {};
    },
    variables: function () {
        if (!this._variables) {
            this._variables = !this.rules ? {} : this.rules.reduce(function (hash, r) {
                if (r instanceof tree.Rule && r.variable === true) {
                    hash[r.name] = r;
                }
                return hash;
            }, {});
        }
        return this._variables;
    },
    variable: function (name) {
        return this.variables()[name];
    },
    rulesets: function () {
        if (!this.rules) { return null; }

        var _Ruleset = tree.Ruleset, _MixinDefinition = tree.mixin.Definition,
            filtRules = [], rules = this.rules, cnt = rules.length,
            i, rule;

        for (i = 0; i < cnt; i++) {
            rule = rules[i];
            if ((rule instanceof _Ruleset) || (rule instanceof _MixinDefinition)) {
                filtRules.push(rule);
            }
        }

        return filtRules;
    },
    prependRule: function (rule) {
        var rules = this.rules;
        if (rules) { rules.unshift(rule); } else { this.rules = [ rule ]; }
    },
    find: function (selector, self) {
        self = self || this;
        var rules = [], match,
            key = selector.toCSS();

        if (key in this._lookups) { return this._lookups[key]; }

        this.rulesets().forEach(function (rule) {
            if (rule !== self) {
                for (var j = 0; j < rule.selectors.length; j++) {
                    match = selector.match(rule.selectors[j]);
                    if (match) {
                        if (selector.elements.length > match) {
                            Array.prototype.push.apply(rules, rule.find(
                                new(tree.Selector)(selector.elements.slice(match)), self));
                        } else {
                            rules.push(rule);
                        }
                        break;
                    }
                }
            }
        });
        this._lookups[key] = rules;
        return rules;
    },
    genCSS: function (env, output) {
        var i, j,
            ruleNodes = [],
            rulesetNodes = [],
            rulesetNodeCnt,
            debugInfo,     // Line number debugging
            rule,
            path;

        env.tabLevel = (env.tabLevel || 0);

        if (!this.root) {
            env.tabLevel++;
        }

        var tabRuleStr = env.compress ? '' : Array(env.tabLevel + 1).join("  "),
            tabSetStr = env.compress ? '' : Array(env.tabLevel).join("  "),
            sep;

        for (i = 0; i < this.rules.length; i++) {
            rule = this.rules[i];
            if (rule.rules || (rule instanceof tree.Media) || rule instanceof tree.Directive || (this.root && rule instanceof tree.Comment)) {
                rulesetNodes.push(rule);
            } else {
                ruleNodes.push(rule);
            }
        }

        // If this is the root node, we don't render
        // a selector, or {}.
        if (!this.root) {
            debugInfo = tree.debugInfo(env, this, tabSetStr);

            if (debugInfo) {
                output.add(debugInfo);
                output.add(tabSetStr);
            }

            var paths = this.paths, pathCnt = paths.length,
                pathSubCnt;

            sep = env.compress ? ',' : (',\n' + tabSetStr);

            for (i = 0; i < pathCnt; i++) {
                path = paths[i];
                if (!(pathSubCnt = path.length)) { continue; }
                if (i > 0) { output.add(sep); }

                env.firstSelector = true;
                path[0].genCSS(env, output);

                env.firstSelector = false;
                for (j = 1; j < pathSubCnt; j++) {
                    path[j].genCSS(env, output);
                }
            }

            output.add((env.compress ? '{' : ' {\n') + tabRuleStr);
        }

        // Compile rules and rulesets
        for (i = 0; i < ruleNodes.length; i++) {
            rule = ruleNodes[i];

            // @page{ directive ends up with root elements inside it, a mix of rules and rulesets
            // In this instance we do not know whether it is the last property
            if (i + 1 === ruleNodes.length && (!this.root || rulesetNodes.length === 0 || this.firstRoot)) {
                env.lastRule = true;
            }

            if (rule.genCSS) {
                rule.genCSS(env, output);
            } else if (rule.value) {
                output.add(rule.value.toString());
            }

            if (!env.lastRule) {
                output.add(env.compress ? '' : ('\n' + tabRuleStr));
            } else {
                env.lastRule = false;
            }
        }

        if (!this.root) {
            output.add((env.compress ? '}' : '\n' + tabSetStr + '}'));
            env.tabLevel--;
        }

        sep = (env.compress ? "" : "\n") + (this.root ? tabRuleStr : tabSetStr);
        rulesetNodeCnt = rulesetNodes.length;
        if (rulesetNodeCnt) {
            if (ruleNodes.length && sep) { output.add(sep); }
            rulesetNodes[0].genCSS(env, output);
            for (i = 1; i < rulesetNodeCnt; i++) {
                if (sep) { output.add(sep); }
                rulesetNodes[i].genCSS(env, output);
            }
        }

        if (!output.isEmpty() && !env.compress && this.firstRoot) {
            output.add('\n');
        }
    },

    toCSS: tree.toCSS,

    markReferenced: function () {
        for (var s = 0; s < this.selectors.length; s++) {
            this.selectors[s].markReferenced();
        }
    },

    joinSelectors: function (paths, context, selectors) {
        for (var s = 0; s < selectors.length; s++) {
            this.joinSelector(paths, context, selectors[s]);
        }
    },

    joinSelector: function (paths, context, selector) {

        var i, j, k, 
            hasParentSelector, newSelectors, el, sel, parentSel, 
            newSelectorPath, afterParentJoin, newJoinedSelector, 
            newJoinedSelectorEmpty, lastSelector, currentElements,
            selectorsMultiplied;
    
        for (i = 0; i < selector.elements.length; i++) {
            el = selector.elements[i];
            if (el.value === '&') {
                hasParentSelector = true;
            }
        }
    
        if (!hasParentSelector) {
            if (context.length > 0) {
                for (i = 0; i < context.length; i++) {
                    paths.push(context[i].concat(selector));
                }
            }
            else {
                paths.push([selector]);
            }
            return;
        }

        // The paths are [[Selector]]
        // The first list is a list of comma seperated selectors
        // The inner list is a list of inheritance seperated selectors
        // e.g.
        // .a, .b {
        //   .c {
        //   }
        // }
        // == [[.a] [.c]] [[.b] [.c]]
        //

        // the elements from the current selector so far
        currentElements = [];
        // the current list of new selectors to add to the path.
        // We will build it up. We initiate it with one empty selector as we "multiply" the new selectors
        // by the parents
        newSelectors = [[]];

        for (i = 0; i < selector.elements.length; i++) {
            el = selector.elements[i];
            // non parent reference elements just get added
            if (el.value !== "&") {
                currentElements.push(el);
            } else {
                // the new list of selectors to add
                selectorsMultiplied = [];

                // merge the current list of non parent selector elements
                // on to the current list of selectors to add
                if (currentElements.length > 0) {
                    this.mergeElementsOnToSelectors(currentElements, newSelectors);
                }

                // loop through our current selectors
                for (j = 0; j < newSelectors.length; j++) {
                    sel = newSelectors[j];
                    // if we don't have any parent paths, the & might be in a mixin so that it can be used
                    // whether there are parents or not
                    if (context.length === 0) {
                        // the combinator used on el should now be applied to the next element instead so that
                        // it is not lost
                        if (sel.length > 0) {
                            sel[0].elements = sel[0].elements.slice(0);
                            sel[0].elements.push(new(tree.Element)(el.combinator, '', 0, el.index, el.currentFileInfo));
                        }
                        selectorsMultiplied.push(sel);
                    }
                    else {
                        // and the parent selectors
                        for (k = 0; k < context.length; k++) {
                            parentSel = context[k];
                            // We need to put the current selectors
                            // then join the last selector's elements on to the parents selectors

                            // our new selector path
                            newSelectorPath = [];
                            // selectors from the parent after the join
                            afterParentJoin = [];
                            newJoinedSelectorEmpty = true;

                            //construct the joined selector - if & is the first thing this will be empty,
                            // if not newJoinedSelector will be the last set of elements in the selector
                            if (sel.length > 0) {
                                newSelectorPath = sel.slice(0);
                                lastSelector = newSelectorPath.pop();
                                newJoinedSelector = selector.createDerived(lastSelector.elements.slice(0));
                                newJoinedSelectorEmpty = false;
                            }
                            else {
                                newJoinedSelector = selector.createDerived([]);
                            }

                            //put together the parent selectors after the join
                            if (parentSel.length > 1) {
                                afterParentJoin = afterParentJoin.concat(parentSel.slice(1));
                            }

                            if (parentSel.length > 0) {
                                newJoinedSelectorEmpty = false;

                                // join the elements so far with the first part of the parent
                                newJoinedSelector.elements.push(new(tree.Element)(el.combinator, parentSel[0].elements[0].value, el.index, el.currentFileInfo));
                                newJoinedSelector.elements = newJoinedSelector.elements.concat(parentSel[0].elements.slice(1));
                            }

                            if (!newJoinedSelectorEmpty) {
                                // now add the joined selector
                                newSelectorPath.push(newJoinedSelector);
                            }

                            // and the rest of the parent
                            newSelectorPath = newSelectorPath.concat(afterParentJoin);

                            // add that to our new set of selectors
                            selectorsMultiplied.push(newSelectorPath);
                        }
                    }
                }

                // our new selectors has been multiplied, so reset the state
                newSelectors = selectorsMultiplied;
                currentElements = [];
            }
        }

        // if we have any elements left over (e.g. .a& .b == .b)
        // add them on to all the current selectors
        if (currentElements.length > 0) {
            this.mergeElementsOnToSelectors(currentElements, newSelectors);
        }

        for (i = 0; i < newSelectors.length; i++) {
            if (newSelectors[i].length > 0) {
                paths.push(newSelectors[i]);
            }
        }
    },
    
    mergeElementsOnToSelectors: function(elements, selectors) {
        var i, sel;

        if (selectors.length === 0) {
            selectors.push([ new(tree.Selector)(elements) ]);
            return;
        }

        for (i = 0; i < selectors.length; i++) {
            sel = selectors[i];

            // if the previous thing in sel is a parent this needs to join on to it
            if (sel.length > 0) {
                sel[sel.length - 1] = sel[sel.length - 1].createDerived(sel[sel.length - 1].elements.concat(elements));
            }
            else {
                sel.push(new(tree.Selector)(elements));
            }
        }
    }
};
})(require('../tree'));

(function (tree) {

tree.Selector = function (elements, extendList, condition, index, currentFileInfo, isReferenced) {
    this.elements = elements;
    this.extendList = extendList;
    this.condition = condition;
    this.currentFileInfo = currentFileInfo || {};
    this.isReferenced = isReferenced;
    if (!condition) {
        this.evaldCondition = true;
    }
};
tree.Selector.prototype = {
    type: "Selector",
    accept: function (visitor) {
        if (this.elements) {
            this.elements = visitor.visitArray(this.elements);
        }
        if (this.extendList) {
            this.extendList = visitor.visitArray(this.extendList);
        }
        if (this.condition) {
            this.condition = visitor.visit(this.condition);
        }
    },
    createDerived: function(elements, extendList, evaldCondition) {
        evaldCondition = (evaldCondition != null) ? evaldCondition : this.evaldCondition;
        var newSelector = new(tree.Selector)(elements, extendList || this.extendList, this.condition, this.index, this.currentFileInfo, this.isReferenced);
        newSelector.evaldCondition = evaldCondition;
        return newSelector;
    },
    match: function (other) {
        var elements = this.elements,
            len = elements.length,
            oelements, olen, i;
            
        oelements = other.elements.map( function(v) {
            return v.combinator.value + (v.value.value || v.value);
        }).join("").match(/[,&#\.\w-]([\w-]|(\\.))*/g); 
        // ^ regexp could be more simple but see test/less/css-escapes.less:17, doh!
        
        if (!oelements) {
            return 0;
        }

        if (oelements[0] === "&") {
            oelements.shift();
        }

        olen = oelements.length;
        if (olen === 0 || len < olen) {
            return 0;
        } else {
            for (i = 0; i < olen; i++) {
                if (elements[i].value !== oelements[i]) {
                    return 0;
                }
            }
        }
        return olen; // return number of matched elements
    },
    eval: function (env) {
        var evaldCondition = this.condition && this.condition.eval(env),
            elements = this.elements, extendList = this.extendList;

        elements = elements && elements.map(function (e) { return e.eval(env); });
        extendList = extendList && extendList.map(function(extend) { return extend.eval(env); });

        return this.createDerived(elements, extendList, evaldCondition);
    },
    genCSS: function (env, output) {
        var i, element;
        if ((!env || !env.firstSelector) && this.elements[0].combinator.value === "") {
            output.add(' ', this.currentFileInfo, this.index);
        }
        if (!this._css) {
            //TODO caching? speed comparison?
            for(i = 0; i < this.elements.length; i++) {
                element = this.elements[i];
                element.genCSS(env, output);
            }
        }
    },
    toCSS: tree.toCSS,
    markReferenced: function () {
        this.isReferenced = true;
    },
    getIsReferenced: function() {
        return !this.currentFileInfo.reference || this.isReferenced;
    },
    getIsOutput: function() {
        return this.evaldCondition;
    }
};

})(require('../tree'));

(function (tree) {

tree.UnicodeDescriptor = function (value) {
    this.value = value;
};
tree.UnicodeDescriptor.prototype = {
    type: "UnicodeDescriptor",
    genCSS: function (env, output) {
        output.add(this.value);
    },
    toCSS: tree.toCSS,
    eval: function () { return this; }
};

})(require('../tree'));

(function (tree) {

tree.URL = function (val, currentFileInfo, isEvald) {
    this.value = val;
    this.currentFileInfo = currentFileInfo;
    this.isEvald = isEvald;
};
tree.URL.prototype = {
    type: "Url",
    accept: function (visitor) {
        this.value = visitor.visit(this.value);
    },
    genCSS: function (env, output) {
        output.add("url(");
        this.value.genCSS(env, output);
        output.add(")");
    },
    toCSS: tree.toCSS,
    eval: function (ctx) {
        var val = this.value.eval(ctx),
            rootpath;

        if (!this.isEvald) {
            // Add the base path if the URL is relative
            rootpath = this.currentFileInfo && this.currentFileInfo.rootpath;
            if (rootpath && typeof val.value === "string" && ctx.isPathRelative(val.value)) {
                if (!val.quote) {
                    rootpath = rootpath.replace(/[\(\)'"\s]/g, function(match) { return "\\"+match; });
                }
                val.value = rootpath + val.value;
            }
            
            val.value = ctx.normalizePath(val.value);
        }

        return new(tree.URL)(val, this.currentFileInfo, true);
    }
};

})(require('../tree'));

(function (tree) {

tree.Value = function (value) {
    this.value = value;
};
tree.Value.prototype = {
    type: "Value",
    accept: function (visitor) {
        if (this.value) {
            this.value = visitor.visitArray(this.value);
        }
    },
    eval: function (env) {
        if (this.value.length === 1) {
            return this.value[0].eval(env);
        } else {
            return new(tree.Value)(this.value.map(function (v) {
                return v.eval(env);
            }));
        }
    },
    genCSS: function (env, output) {
        var i;
        for(i = 0; i < this.value.length; i++) {
            this.value[i].genCSS(env, output);
            if (i+1 < this.value.length) {
                output.add((env && env.compress) ? ',' : ', ');
            }
        }
    },
    toCSS: tree.toCSS
};

})(require('../tree'));

(function (tree) {

tree.Variable = function (name, index, currentFileInfo) {
    this.name = name;
    this.index = index;
    this.currentFileInfo = currentFileInfo || {};
};
tree.Variable.prototype = {
    type: "Variable",
    eval: function (env) {
        var variable, name = this.name;

        if (name.indexOf('@@') === 0) {
            name = '@' + new(tree.Variable)(name.slice(1)).eval(env).value;
        }
        
        if (this.evaluating) {
            throw { type: 'Name',
                    message: "Recursive variable definition for " + name,
                    filename: this.currentFileInfo.file,
                    index: this.index };
        }
        
        this.evaluating = true;

        variable = tree.find(env.frames, function (frame) {
            var v = frame.variable(name);
            if (v) {
                return v.value.eval(env);
            }
        });
        if (variable) { 
            this.evaluating = false;
            return variable;
        } else {
            throw { type: 'Name',
                    message: "variable " + name + " is undefined",
                    filename: this.currentFileInfo.filename,
                    index: this.index };
        }
    }
};

})(require('../tree'));

(function (tree) {

    var parseCopyProperties = [
        'paths',            // option - unmodified - paths to search for imports on
        'optimization',     // option - optimization level (for the chunker)
        'files',            // list of files that have been imported, used for import-once
        'contents',         // map - filename to contents of all the files
        'contentsIgnoredChars', // map - filename to lines at the begining of each file to ignore
        'relativeUrls',     // option - whether to adjust URL's to be relative
        'rootpath',         // option - rootpath to append to URL's
        'strictImports',    // option -
        'insecure',         // option - whether to allow imports from insecure ssl hosts
        'dumpLineNumbers',  // option - whether to dump line numbers
        'compress',         // option - whether to compress
        'processImports',   // option - whether to process imports. if false then imports will not be imported
        'syncImport',       // option - whether to import synchronously
        'javascriptEnabled',// option - whether JavaScript is enabled. if undefined, defaults to true
        'mime',             // browser only - mime type for sheet import
        'useFileCache',     // browser only - whether to use the per file session cache
        'currentFileInfo'   // information about the current file - for error reporting and importing and making urls relative etc.
    ];

    //currentFileInfo = {
    //  'relativeUrls' - option - whether to adjust URL's to be relative
    //  'filename' - full resolved filename of current file
    //  'rootpath' - path to append to normal URLs for this node
    //  'currentDirectory' - path to the current file, absolute
    //  'rootFilename' - filename of the base file
    //  'entryPath' - absolute path to the entry file
    //  'reference' - whether the file should not be output and only output parts that are referenced

    tree.parseEnv = function(options) {
        copyFromOriginal(options, this, parseCopyProperties);

        if (!this.contents) { this.contents = {}; }
        if (!this.contentsIgnoredChars) { this.contentsIgnoredChars = {}; }
        if (!this.files) { this.files = {}; }

        if (!this.currentFileInfo) {
            var filename = (options && options.filename) || "input";
            var entryPath = filename.replace(/[^\/\\]*$/, "");
            if (options) {
                options.filename = null;
            }
            this.currentFileInfo = {
                filename: filename,
                relativeUrls: this.relativeUrls,
                rootpath: (options && options.rootpath) || "",
                currentDirectory: entryPath,
                entryPath: entryPath,
                rootFilename: filename
            };
        }
    };

    var evalCopyProperties = [
        'silent',      // whether to swallow errors and warnings
        'verbose',     // whether to log more activity
        'compress',    // whether to compress
        'yuicompress', // whether to compress with the outside tool yui compressor
        'ieCompat',    // whether to enforce IE compatibility (IE8 data-uri)
        'strictMath',  // whether math has to be within parenthesis
        'strictUnits', // whether units need to evaluate correctly
        'cleancss',    // whether to compress with clean-css
        'sourceMap',   // whether to output a source map
        'importMultiple'// whether we are currently importing multiple copies
        ];

    tree.evalEnv = function(options, frames) {
        copyFromOriginal(options, this, evalCopyProperties);

        this.frames = frames || [];
    };

    tree.evalEnv.prototype.inParenthesis = function () {
        if (!this.parensStack) {
            this.parensStack = [];
        }
        this.parensStack.push(true);
    };

    tree.evalEnv.prototype.outOfParenthesis = function () {
        this.parensStack.pop();
    };

    tree.evalEnv.prototype.isMathOn = function () {
        return this.strictMath ? (this.parensStack && this.parensStack.length) : true;
    };

    tree.evalEnv.prototype.isPathRelative = function (path) {
        return !/^(?:[a-z-]+:|\/)/.test(path);
    };

    tree.evalEnv.prototype.normalizePath = function( path ) {
        var
          segments = path.split("/").reverse(),
          segment;

        path = [];
        while (segments.length !== 0 ) {
            segment = segments.pop();
            switch( segment ) {
                case ".":
                    break;
                case "..":
                    if ((path.length === 0) || (path[path.length - 1] === "..")) {
                        path.push( segment );
                    } else {
                        path.pop();
                    }
                    break;
                default:
                    path.push( segment );
                    break;
            }
        }

        return path.join("/");
    };

    //todo - do the same for the toCSS env
    //tree.toCSSEnv = function (options) {
    //};

    var copyFromOriginal = function(original, destination, propertiesToCopy) {
        if (!original) { return; }

        for(var i = 0; i < propertiesToCopy.length; i++) {
            if (original.hasOwnProperty(propertiesToCopy[i])) {
                destination[propertiesToCopy[i]] = original[propertiesToCopy[i]];
            }
        }
    };

})(require('./tree'));

(function (tree) {

    var _visitArgs = { visitDeeper: true },
        _hasIndexed = false;

    function _noop(node) {
        return node;
    }

    function indexNodeTypes(parent, ticker) {
        // add .typeIndex to tree node types for lookup table
        var key, child;
        for (key in parent) {
            child = parent[key];
            switch (typeof child) {
                case "function":
                    // ignore bound functions directly on tree which do not have a prototype
                    // or aren't nodes
                    if (child.prototype && child.prototype.type) {
                        child.prototype.typeIndex = ticker++;
                    }
                    break;
                case "object":
                    ticker = indexNodeTypes(child, ticker);
                    break;
            }
        }
        return ticker;
    }

    tree.visitor = function(implementation) {
        this._implementation = implementation;
        this._visitFnCache = [];

        if (!_hasIndexed) {
            indexNodeTypes(tree, 1);
            _hasIndexed = true;
        }
    };

    tree.visitor.prototype = {
        visit: function(node) {
            if (!node) {
                return node;
            }

            var nodeTypeIndex = node.typeIndex;
            if (!nodeTypeIndex) {
                return node;
            }

            var visitFnCache = this._visitFnCache,
                impl = this._implementation,
                aryIndx = nodeTypeIndex << 1,
                outAryIndex = aryIndx | 1,
                func = visitFnCache[aryIndx],
                funcOut = visitFnCache[outAryIndex],
                visitArgs = _visitArgs,
                fnName;

            visitArgs.visitDeeper = true;

            if (!func) {
                fnName = "visit" + node.type;
                func = impl[fnName] || _noop;
                funcOut = impl[fnName + "Out"] || _noop;
                visitFnCache[aryIndx] = func;
                visitFnCache[outAryIndex] = funcOut;
            }

            if (func !== _noop) {
                var newNode = func.call(impl, node, visitArgs);
                if (impl.isReplacing) {
                    node = newNode;
                }
            }

            if (visitArgs.visitDeeper && node && node.accept) {
                node.accept(this);
            }

            if (funcOut != _noop) {
                funcOut.call(impl, node);
            }

            return node;
        },
        visitArray: function(nodes, nonReplacing) {
            if (!nodes) {
                return nodes;
            }

            var cnt = nodes.length, i;

            // Non-replacing
            if (nonReplacing || !this._implementation.isReplacing) {
                for (i = 0; i < cnt; i++) {
                    this.visit(nodes[i]);
                }
                return nodes;
            }

            // Replacing
            var out = [];
            for (i = 0; i < cnt; i++) {
                var evald = this.visit(nodes[i]);
                if (!evald.splice) {
                    out.push(evald);
                } else if (evald.length) {
                    this.flatten(evald, out);
                }
            }
            return out;
        },
        flatten: function(arr, out) {
            if (!out) {
                out = [];
            }

            var cnt, i, item,
                nestedCnt, j, nestedItem;

            for (i = 0, cnt = arr.length; i < cnt; i++) {
                item = arr[i];
                if (!item.splice) {
                    out.push(item);
                    continue;
                }

                for (j = 0, nestedCnt = item.length; j < nestedCnt; j++) {
                    nestedItem = item[j];
                    if (!nestedItem.splice) {
                        out.push(nestedItem);
                    } else if (nestedItem.length) {
                        this.flatten(nestedItem, out);
                    }
                }
            }

            return out;
        }
    };

})(require('./tree'));
(function (tree) {
    tree.importVisitor = function(importer, finish, evalEnv) {
        this._visitor = new tree.visitor(this);
        this._importer = importer;
        this._finish = finish;
        this.env = evalEnv || new tree.evalEnv();
        this.importCount = 0;
    };

    tree.importVisitor.prototype = {
        isReplacing: true,
        run: function (root) {
            var error;
            try {
                // process the contents
                this._visitor.visit(root);
            }
            catch(e) {
                error = e;
            }

            this.isFinished = true;

            if (this.importCount === 0) {
                this._finish(error);
            }
        },
        visitImport: function (importNode, visitArgs) {
            var importVisitor = this,
                evaldImportNode,
                inlineCSS = importNode.options.inline;

            if (!importNode.css || inlineCSS) {

                try {
                    evaldImportNode = importNode.evalForImport(this.env);
                } catch(e){
                    if (!e.filename) { e.index = importNode.index; e.filename = importNode.currentFileInfo.filename; }
                    // attempt to eval properly and treat as css
                    importNode.css = true;
                    // if that fails, this error will be thrown
                    importNode.error = e;
                }

                if (evaldImportNode && (!evaldImportNode.css || inlineCSS)) {
                    importNode = evaldImportNode;
                    this.importCount++;
                    var env = new tree.evalEnv(this.env, this.env.frames.slice(0));

                    if (importNode.options.multiple) {
                        env.importMultiple = true;
                    }

                    this._importer.push(importNode.getPath(), importNode.currentFileInfo, importNode.options, function (e, root, imported, fullPath) {
                        if (e && !e.filename) { e.index = importNode.index; e.filename = importNode.currentFileInfo.filename; }

                        if (imported && !env.importMultiple) { importNode.skip = imported; }

                        var subFinish = function(e) {
                            importVisitor.importCount--;

                            if (importVisitor.importCount === 0 && importVisitor.isFinished) {
                                importVisitor._finish(e);
                            }
                        };

                        if (root) {
                            importNode.root = root;
                            importNode.importedFilename = fullPath;
                            if (!inlineCSS && !importNode.skip) {
                                new(tree.importVisitor)(importVisitor._importer, subFinish, env)
                                    .run(root);
                                return;
                            }
                        }

                        subFinish();
                    });
                }
            }
            visitArgs.visitDeeper = false;
            return importNode;
        },
        visitRule: function (ruleNode, visitArgs) {
            visitArgs.visitDeeper = false;
            return ruleNode;
        },
        visitDirective: function (directiveNode, visitArgs) {
            this.env.frames.unshift(directiveNode);
            return directiveNode;
        },
        visitDirectiveOut: function (directiveNode) {
            this.env.frames.shift();
        },
        visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
            this.env.frames.unshift(mixinDefinitionNode);
            return mixinDefinitionNode;
        },
        visitMixinDefinitionOut: function (mixinDefinitionNode) {
            this.env.frames.shift();
        },
        visitRuleset: function (rulesetNode, visitArgs) {
            this.env.frames.unshift(rulesetNode);
            return rulesetNode;
        },
        visitRulesetOut: function (rulesetNode) {
            this.env.frames.shift();
        },
        visitMedia: function (mediaNode, visitArgs) {
            this.env.frames.unshift(mediaNode.ruleset);
            return mediaNode;
        },
        visitMediaOut: function (mediaNode) {
            this.env.frames.shift();
        }
    };

})(require('./tree'));
(function (tree) {
    tree.joinSelectorVisitor = function() {
        this.contexts = [[]];
        this._visitor = new tree.visitor(this);
    };

    tree.joinSelectorVisitor.prototype = {
        run: function (root) {
            return this._visitor.visit(root);
        },
        visitRule: function (ruleNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },

        visitRuleset: function (rulesetNode, visitArgs) {
            var context = this.contexts[this.contexts.length - 1],
                paths = [], selectors;

            this.contexts.push(paths);

            if (! rulesetNode.root) {
                selectors = rulesetNode.selectors;
                if (selectors) {
                    selectors = selectors.filter(function(selector) { return selector.getIsOutput(); });
                    rulesetNode.selectors = selectors.length ? selectors : (selectors = null);
                    if (selectors) { rulesetNode.joinSelectors(paths, context, selectors); }
                }
                if (!selectors) { rulesetNode.rules = null; }
                rulesetNode.paths = paths;
            }
        },
        visitRulesetOut: function (rulesetNode) {
            this.contexts.length = this.contexts.length - 1;
        },
        visitMedia: function (mediaNode, visitArgs) {
            var context = this.contexts[this.contexts.length - 1];
            mediaNode.rules[0].root = (context.length === 0 || context[0].multiMedia);
        }
    };

})(require('./tree'));
(function (tree) {
    tree.toCSSVisitor = function(env) {
        this._visitor = new tree.visitor(this);
        this._env = env;
    };

    tree.toCSSVisitor.prototype = {
        isReplacing: true,
        run: function (root) {
            return this._visitor.visit(root);
        },

        visitRule: function (ruleNode, visitArgs) {
            if (ruleNode.variable) {
                return [];
            }
            return ruleNode;
        },

        visitMixinDefinition: function (mixinNode, visitArgs) {
            return [];
        },

        visitExtend: function (extendNode, visitArgs) {
            return [];
        },

        visitComment: function (commentNode, visitArgs) {
            if (commentNode.isSilent(this._env)) {
                return [];
            }
            return commentNode;
        },

        visitMedia: function(mediaNode, visitArgs) {
            mediaNode.accept(this._visitor);
            visitArgs.visitDeeper = false;

            if (!mediaNode.rules.length) {
                return [];
            }
            return mediaNode;
        },

        visitDirective: function(directiveNode, visitArgs) {
            if (directiveNode.currentFileInfo.reference && !directiveNode.isReferenced) {
                return [];
            }
            if (directiveNode.name === "@charset") {
                // Only output the debug info together with subsequent @charset definitions
                // a comment (or @media statement) before the actual @charset directive would
                // be considered illegal css as it has to be on the first line
                if (this.charset) {
                    if (directiveNode.debugInfo) {
                        var comment = new tree.Comment("/* " + directiveNode.toCSS(this._env).replace(/\n/g, "")+" */\n");
                        comment.debugInfo = directiveNode.debugInfo;
                        return this._visitor.visit(comment);
                    }
                    return [];
                }
                this.charset = true;
            }
            return directiveNode;
        },

        checkPropertiesInRoot: function(rules) {
            var ruleNode;
            for(var i = 0; i < rules.length; i++) {
                ruleNode = rules[i];
                if (ruleNode instanceof tree.Rule && !ruleNode.variable) {
                    throw { message: "properties must be inside selector blocks, they cannot be in the root.",
                        index: ruleNode.index, filename: ruleNode.currentFileInfo ? ruleNode.currentFileInfo.filename : null};
                }
            }
        },

        visitRuleset: function (rulesetNode, visitArgs) {
            var rule, rulesets = [];
            if (rulesetNode.firstRoot) {
                this.checkPropertiesInRoot(rulesetNode.rules);
            }
            if (! rulesetNode.root) {
                if (rulesetNode.paths) {
                    rulesetNode.paths = rulesetNode.paths
                        .filter(function(p) {
                            var i;
                            if (p[0].elements[0].combinator.value === ' ') {
                                p[0].elements[0].combinator = new(tree.Combinator)('');
                            }
                            for(i = 0; i < p.length; i++) {
                                if (p[i].getIsReferenced() && p[i].getIsOutput()) {
                                    return true;
                                }
                            }
                            return false;
                        });
                }

                // Compile rules and rulesets
                var nodeRules = rulesetNode.rules, nodeRuleCnt = nodeRules ? nodeRules.length : 0;
                for (var i = 0; i < nodeRuleCnt; ) {
                    rule = nodeRules[i];
                    if (rule && rule.rules) {
                        // visit because we are moving them out from being a child
                        rulesets.push(this._visitor.visit(rule));
                        nodeRules.splice(i, 1);
                        nodeRuleCnt--;
                        continue;
                    }
                    i++;
                }
                // accept the visitor to remove rules and refactor itself
                // then we can decide now whether we want it or not
                if (nodeRuleCnt > 0) {
                    rulesetNode.accept(this._visitor);
                } else {
                    rulesetNode.rules = null;
                }
                visitArgs.visitDeeper = false;

                nodeRules = rulesetNode.rules;
                if (nodeRules) {
                    this._mergeRules(nodeRules);
                    nodeRules = rulesetNode.rules;
                }
                if (nodeRules) {
                    this._removeDuplicateRules(nodeRules);
                    nodeRules = rulesetNode.rules;
                }

                // now decide whether we keep the ruleset
                if (nodeRules && nodeRules.length > 0 && rulesetNode.paths.length > 0) {
                    rulesets.splice(0, 0, rulesetNode);
                }
            } else {
                rulesetNode.accept(this._visitor);
                visitArgs.visitDeeper = false;
                if (rulesetNode.firstRoot || (rulesetNode.rules && rulesetNode.rules.length > 0)) {
                    rulesets.splice(0, 0, rulesetNode);
                }
            }
            if (rulesets.length === 1) {
                return rulesets[0];
            }
            return rulesets;
        },

        _removeDuplicateRules: function(rules) {
            if (!rules) { return; }

            // remove duplicates
            var ruleCache = {},
                ruleList, rule, i;

            for(i = rules.length - 1; i >= 0 ; i--) {
                rule = rules[i];
                if (rule instanceof tree.Rule) {
                    if (!ruleCache[rule.name]) {
                        ruleCache[rule.name] = rule;
                    } else {
                        ruleList = ruleCache[rule.name];
                        if (ruleList instanceof tree.Rule) {
                            ruleList = ruleCache[rule.name] = [ruleCache[rule.name].toCSS(this._env)];
                        }
                        var ruleCSS = rule.toCSS(this._env);
                        if (ruleList.indexOf(ruleCSS) !== -1) {
                            rules.splice(i, 1);
                        } else {
                            ruleList.push(ruleCSS);
                        }
                    }
                }
            }
        },

        _mergeRules: function (rules) {
            if (!rules) { return; }

            var groups = {},
                parts,
                rule,
                key;

            for (var i = 0; i < rules.length; i++) {
                rule = rules[i];

                if ((rule instanceof tree.Rule) && rule.merge) {
                    key = [rule.name,
                        rule.important ? "!" : ""].join(",");

                    if (!groups[key]) {
                        groups[key] = [];
                    } else {
                        rules.splice(i--, 1);
                    }

                    groups[key].push(rule);
                }
            }

            Object.keys(groups).map(function (k) {
                parts = groups[k];

                if (parts.length > 1) {
                    rule = parts[0];

                    rule.value = new (tree.Value)(parts.map(function (p) {
                        return p.value;
                    }));
                }
            });
        }
    };

})(require('./tree'));
(function (tree) {
    /*jshint loopfunc:true */

    tree.extendFinderVisitor = function() {
        this._visitor = new tree.visitor(this);
        this.contexts = [];
        this.allExtendsStack = [[]];
    };

    tree.extendFinderVisitor.prototype = {
        run: function (root) {
            root = this._visitor.visit(root);
            root.allExtends = this.allExtendsStack[0];
            return root;
        },
        visitRule: function (ruleNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitRuleset: function (rulesetNode, visitArgs) {
            if (rulesetNode.root) {
                return;
            }

            var i, j, extend, allSelectorsExtendList = [], extendList;

            // get &:extend(.a); rules which apply to all selectors in this ruleset
            var rules = rulesetNode.rules, ruleCnt = rules ? rules.length : 0;
            for(i = 0; i < ruleCnt; i++) {
                if (rulesetNode.rules[i] instanceof tree.Extend) {
                    allSelectorsExtendList.push(rules[i]);
                    rulesetNode.extendOnEveryPath = true;
                }
            }

            // now find every selector and apply the extends that apply to all extends
            // and the ones which apply to an individual extend
            var paths = rulesetNode.paths;
            for(i = 0; i < paths.length; i++) {
                var selectorPath = paths[i],
                    selector = selectorPath[selectorPath.length - 1],
                    selExtendList = selector.extendList;

                extendList = selExtendList ? selExtendList.slice(0).concat(allSelectorsExtendList)
                                           : allSelectorsExtendList;

                if (extendList) {
                    extendList = extendList.map(function(allSelectorsExtend) {
                        return allSelectorsExtend.clone();
                    });
                }

                for(j = 0; j < extendList.length; j++) {
                    this.foundExtends = true;
                    extend = extendList[j];
                    extend.findSelfSelectors(selectorPath);
                    extend.ruleset = rulesetNode;
                    if (j === 0) { extend.firstExtendOnThisSelectorPath = true; }
                    this.allExtendsStack[this.allExtendsStack.length-1].push(extend);
                }
            }

            this.contexts.push(rulesetNode.selectors);
        },
        visitRulesetOut: function (rulesetNode) {
            if (!rulesetNode.root) {
                this.contexts.length = this.contexts.length - 1;
            }
        },
        visitMedia: function (mediaNode, visitArgs) {
            mediaNode.allExtends = [];
            this.allExtendsStack.push(mediaNode.allExtends);
        },
        visitMediaOut: function (mediaNode) {
            this.allExtendsStack.length = this.allExtendsStack.length - 1;
        },
        visitDirective: function (directiveNode, visitArgs) {
            directiveNode.allExtends = [];
            this.allExtendsStack.push(directiveNode.allExtends);
        },
        visitDirectiveOut: function (directiveNode) {
            this.allExtendsStack.length = this.allExtendsStack.length - 1;
        }
    };

    tree.processExtendsVisitor = function() {
        this._visitor = new tree.visitor(this);
    };

    tree.processExtendsVisitor.prototype = {
        run: function(root) {
            var extendFinder = new tree.extendFinderVisitor();
            extendFinder.run(root);
            if (!extendFinder.foundExtends) { return root; }
            root.allExtends = root.allExtends.concat(this.doExtendChaining(root.allExtends, root.allExtends));
            this.allExtendsStack = [root.allExtends];
            return this._visitor.visit(root);
        },
        doExtendChaining: function (extendsList, extendsListTarget, iterationCount) {
            //
            // chaining is different from normal extension.. if we extend an extend then we are not just copying, altering and pasting
            // the selector we would do normally, but we are also adding an extend with the same target selector
            // this means this new extend can then go and alter other extends
            //
            // this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
            // this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already processed if
            // we look at each selector at a time, as is done in visitRuleset

            var extendIndex, targetExtendIndex, matches, extendsToAdd = [], newSelector, extendVisitor = this, selectorPath, extend, targetExtend, newExtend;

            iterationCount = iterationCount || 0;

            //loop through comparing every extend with every target extend.
            // a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
            // e.g.  .a:extend(.b) {}  and .b:extend(.c) {} then the first extend extends the second one
            // and the second is the target.
            // the seperation into two lists allows us to process a subset of chains with a bigger set, as is the
            // case when processing media queries
            for(extendIndex = 0; extendIndex < extendsList.length; extendIndex++){
                for(targetExtendIndex = 0; targetExtendIndex < extendsListTarget.length; targetExtendIndex++){

                    extend = extendsList[extendIndex];
                    targetExtend = extendsListTarget[targetExtendIndex];

                    // look for circular references
                    if( extend.parent_ids.indexOf( targetExtend.object_id ) >= 0 ){ continue; }

                    // find a match in the target extends self selector (the bit before :extend)
                    selectorPath = [targetExtend.selfSelectors[0]];
                    matches = extendVisitor.findMatch(extend, selectorPath);

                    if (matches.length) {

                        // we found a match, so for each self selector..
                        extend.selfSelectors.forEach(function(selfSelector) {

                            // process the extend as usual
                            newSelector = extendVisitor.extendSelector(matches, selectorPath, selfSelector);

                            // but now we create a new extend from it
                            newExtend = new(tree.Extend)(targetExtend.selector, targetExtend.option, 0);
                            newExtend.selfSelectors = newSelector;

                            // add the extend onto the list of extends for that selector
                            newSelector[newSelector.length-1].extendList = [newExtend];

                            // record that we need to add it.
                            extendsToAdd.push(newExtend);
                            newExtend.ruleset = targetExtend.ruleset;

                            //remember its parents for circular references
                            newExtend.parent_ids = newExtend.parent_ids.concat(targetExtend.parent_ids, extend.parent_ids);

                            // only process the selector once.. if we have :extend(.a,.b) then multiple
                            // extends will look at the same selector path, so when extending
                            // we know that any others will be duplicates in terms of what is added to the css
                            if (targetExtend.firstExtendOnThisSelectorPath) {
                                newExtend.firstExtendOnThisSelectorPath = true;
                                targetExtend.ruleset.paths.push(newSelector);
                            }
                        });
                    }
                }
            }

            if (extendsToAdd.length) {
                // try to detect circular references to stop a stack overflow.
                // may no longer be needed.
                this.extendChainCount++;
                if (iterationCount > 100) {
                    var selectorOne = "{unable to calculate}";
                    var selectorTwo = "{unable to calculate}";
                    try
                    {
                        selectorOne = extendsToAdd[0].selfSelectors[0].toCSS();
                        selectorTwo = extendsToAdd[0].selector.toCSS();
                    }
                    catch(e) {}
                    throw {message: "extend circular reference detected. One of the circular extends is currently:"+selectorOne+":extend(" + selectorTwo+")"};
                }

                // now process the new extends on the existing rules so that we can handle a extending b extending c ectending d extending e...
                return extendsToAdd.concat(extendVisitor.doExtendChaining(extendsToAdd, extendsListTarget, iterationCount+1));
            } else {
                return extendsToAdd;
            }
        },
        visitRule: function (ruleNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitSelector: function (selectorNode, visitArgs) {
            visitArgs.visitDeeper = false;
        },
        visitRuleset: function (rulesetNode, visitArgs) {
            if (rulesetNode.root) {
                return;
            }
            var matches, pathIndex, extendIndex, allExtends = this.allExtendsStack[this.allExtendsStack.length-1], selectorsToAdd = [], extendVisitor = this, selectorPath;

            // look at each selector path in the ruleset, find any extend matches and then copy, find and replace

            for(extendIndex = 0; extendIndex < allExtends.length; extendIndex++) {
                for(pathIndex = 0; pathIndex < rulesetNode.paths.length; pathIndex++) {
                    selectorPath = rulesetNode.paths[pathIndex];

                    // extending extends happens initially, before the main pass
                    if (rulesetNode.extendOnEveryPath) { continue; }
                    var extendList = selectorPath[selectorPath.length-1].extendList;
                    if (extendList && extendList.length) { continue; }

                    matches = this.findMatch(allExtends[extendIndex], selectorPath);

                    if (matches.length) {

                        allExtends[extendIndex].selfSelectors.forEach(function(selfSelector) {
                            selectorsToAdd.push(extendVisitor.extendSelector(matches, selectorPath, selfSelector));
                        });
                    }
                }
            }
            rulesetNode.paths = rulesetNode.paths.concat(selectorsToAdd);
        },
        findMatch: function (extend, haystackSelectorPath) {
            //
            // look through the haystack selector path to try and find the needle - extend.selector
            // returns an array of selector matches that can then be replaced
            //
            var haystackSelectorIndex, hackstackSelector, hackstackElementIndex, haystackElement,
                targetCombinator, i,
                extendVisitor = this,
                needleElements = extend.selector.elements,
                potentialMatches = [], potentialMatch, matches = [];

            // loop through the haystack elements
            for(haystackSelectorIndex = 0; haystackSelectorIndex < haystackSelectorPath.length; haystackSelectorIndex++) {
                hackstackSelector = haystackSelectorPath[haystackSelectorIndex];

                for(hackstackElementIndex = 0; hackstackElementIndex < hackstackSelector.elements.length; hackstackElementIndex++) {

                    haystackElement = hackstackSelector.elements[hackstackElementIndex];

                    // if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
                    if (extend.allowBefore || (haystackSelectorIndex === 0 && hackstackElementIndex === 0)) {
                        potentialMatches.push({pathIndex: haystackSelectorIndex, index: hackstackElementIndex, matched: 0, initialCombinator: haystackElement.combinator});
                    }

                    for(i = 0; i < potentialMatches.length; i++) {
                        potentialMatch = potentialMatches[i];

                        // selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
                        // then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to work out
                        // what the resulting combinator will be
                        targetCombinator = haystackElement.combinator.value;
                        if (targetCombinator === '' && hackstackElementIndex === 0) {
                            targetCombinator = ' ';
                        }

                        // if we don't match, null our match to indicate failure
                        if (!extendVisitor.isElementValuesEqual(needleElements[potentialMatch.matched].value, haystackElement.value) ||
                            (potentialMatch.matched > 0 && needleElements[potentialMatch.matched].combinator.value !== targetCombinator)) {
                            potentialMatch = null;
                        } else {
                            potentialMatch.matched++;
                        }

                        // if we are still valid and have finished, test whether we have elements after and whether these are allowed
                        if (potentialMatch) {
                            potentialMatch.finished = potentialMatch.matched === needleElements.length;
                            if (potentialMatch.finished &&
                                (!extend.allowAfter && (hackstackElementIndex+1 < hackstackSelector.elements.length || haystackSelectorIndex+1 < haystackSelectorPath.length))) {
                                potentialMatch = null;
                            }
                        }
                        // if null we remove, if not, we are still valid, so either push as a valid match or continue
                        if (potentialMatch) {
                            if (potentialMatch.finished) {
                                potentialMatch.length = needleElements.length;
                                potentialMatch.endPathIndex = haystackSelectorIndex;
                                potentialMatch.endPathElementIndex = hackstackElementIndex + 1; // index after end of match
                                potentialMatches.length = 0; // we don't allow matches to overlap, so start matching again
                                matches.push(potentialMatch);
                            }
                        } else {
                            potentialMatches.splice(i, 1);
                            i--;
                        }
                    }
                }
            }
            return matches;
        },
        isElementValuesEqual: function(elementValue1, elementValue2) {
            if (typeof elementValue1 === "string" || typeof elementValue2 === "string") {
                return elementValue1 === elementValue2;
            }
            if (elementValue1 instanceof tree.Attribute) {
                if (elementValue1.op !== elementValue2.op || elementValue1.key !== elementValue2.key) {
                    return false;
                }
                if (!elementValue1.value || !elementValue2.value) {
                    if (elementValue1.value || elementValue2.value) {
                        return false;
                    }
                    return true;
                }
                elementValue1 = elementValue1.value.value || elementValue1.value;
                elementValue2 = elementValue2.value.value || elementValue2.value;
                return elementValue1 === elementValue2;
            }
            elementValue1 = elementValue1.value;
            elementValue2 = elementValue2.value;
            if (elementValue1 instanceof tree.Selector) {
                if (!(elementValue2 instanceof tree.Selector) || elementValue1.elements.length !== elementValue2.elements.length) {
                    return false;
                }
                for(var i = 0; i <elementValue1.elements.length; i++) {
                    if (elementValue1.elements[i].combinator.value !== elementValue2.elements[i].combinator.value) {
                        if (i !== 0 || (elementValue1.elements[i].combinator.value || ' ') !== (elementValue2.elements[i].combinator.value || ' ')) {
                            return false;
                        }
                    }
                    if (!this.isElementValuesEqual(elementValue1.elements[i].value, elementValue2.elements[i].value)) {
                        return false;
                    }
                }
                return true;
            }
            return false;
        },
        extendSelector:function (matches, selectorPath, replacementSelector) {

            //for a set of matches, replace each match with the replacement selector

            var currentSelectorPathIndex = 0,
                currentSelectorPathElementIndex = 0,
                path = [],
                matchIndex,
                selector,
                firstElement,
                match,
                newElements;

            for (matchIndex = 0; matchIndex < matches.length; matchIndex++) {
                match = matches[matchIndex];
                selector = selectorPath[match.pathIndex];
                firstElement = new tree.Element(
                    match.initialCombinator,
                    replacementSelector.elements[0].value,
                    replacementSelector.elements[0].index,
                    replacementSelector.elements[0].currentFileInfo
                );

                if (match.pathIndex > currentSelectorPathIndex && currentSelectorPathElementIndex > 0) {
                    path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
                    currentSelectorPathElementIndex = 0;
                    currentSelectorPathIndex++;
                }

                newElements = selector.elements
                    .slice(currentSelectorPathElementIndex, match.index)
                    .concat([firstElement])
                    .concat(replacementSelector.elements.slice(1));

                if (currentSelectorPathIndex === match.pathIndex && matchIndex > 0) {
                    path[path.length - 1].elements =
                        path[path.length - 1].elements.concat(newElements);
                } else {
                    path = path.concat(selectorPath.slice(currentSelectorPathIndex, match.pathIndex));

                    path.push(new tree.Selector(
                        newElements
                    ));
                }
                currentSelectorPathIndex = match.endPathIndex;
                currentSelectorPathElementIndex = match.endPathElementIndex;
                if (currentSelectorPathElementIndex >= selectorPath[currentSelectorPathIndex].elements.length) {
                    currentSelectorPathElementIndex = 0;
                    currentSelectorPathIndex++;
                }
            }

            if (currentSelectorPathIndex < selectorPath.length && currentSelectorPathElementIndex > 0) {
                path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
                currentSelectorPathIndex++;
            }

            path = path.concat(selectorPath.slice(currentSelectorPathIndex, selectorPath.length));

            return path;
        },
        visitRulesetOut: function (rulesetNode) {
        },
        visitMedia: function (mediaNode, visitArgs) {
            var newAllExtends = mediaNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length-1]);
            newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, mediaNode.allExtends));
            this.allExtendsStack.push(newAllExtends);
        },
        visitMediaOut: function (mediaNode) {
            this.allExtendsStack.length = this.allExtendsStack.length - 1;
        },
        visitDirective: function (directiveNode, visitArgs) {
            var newAllExtends = directiveNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length-1]);
            newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, directiveNode.allExtends));
            this.allExtendsStack.push(newAllExtends);
        },
        visitDirectiveOut: function (directiveNode) {
            this.allExtendsStack.length = this.allExtendsStack.length - 1;
        }
    };

})(require('./tree'));

(function (tree) {

    tree.sourceMapOutput = function (options) {
        this._css = [];
        this._rootNode = options.rootNode;
        this._writeSourceMap = options.writeSourceMap;
        this._contentsMap = options.contentsMap;
        this._contentsIgnoredCharsMap = options.contentsIgnoredCharsMap;
        this._sourceMapFilename = options.sourceMapFilename;
        this._outputFilename = options.outputFilename;
        this._sourceMapURL = options.sourceMapURL;
        if (options.sourceMapBasepath) {
            this._sourceMapBasepath = options.sourceMapBasepath.replace(/\\/g, '/');
        }
        this._sourceMapRootpath = options.sourceMapRootpath;
        this._outputSourceFiles = options.outputSourceFiles;
        this._sourceMapGeneratorConstructor = options.sourceMapGenerator || require("source-map").SourceMapGenerator;

        if (this._sourceMapRootpath && this._sourceMapRootpath.charAt(this._sourceMapRootpath.length-1) !== '/') {
            this._sourceMapRootpath += '/';
        }

        this._lineNumber = 0;
        this._column = 0;
    };

    tree.sourceMapOutput.prototype.normalizeFilename = function(filename) {
        filename = filename.replace(/\\/g, '/');

        if (this._sourceMapBasepath && filename.indexOf(this._sourceMapBasepath) === 0) {
            filename = filename.substring(this._sourceMapBasepath.length);
            if (filename.charAt(0) === '\\' || filename.charAt(0) === '/') {
               filename = filename.substring(1);
            }
        }
        return (this._sourceMapRootpath || "") + filename;
    };

    tree.sourceMapOutput.prototype.add = function(chunk, fileInfo, index, mapLines) {

        //ignore adding empty strings
        if (!chunk) {
            return;
        }

        var lines,
            sourceLines,
            columns,
            sourceColumns,
            i;

        if (fileInfo) {
            var inputSource = this._contentsMap[fileInfo.filename];
            
            // remove vars/banner added to the top of the file
            if (this._contentsIgnoredCharsMap[fileInfo.filename]) {
                // adjust the index
                index -= this._contentsIgnoredCharsMap[fileInfo.filename];
                if (index < 0) { index = 0; }
                // adjust the source
                inputSource = inputSource.slice(this._contentsIgnoredCharsMap[fileInfo.filename]);
            }
            inputSource = inputSource.substring(0, index);
            sourceLines = inputSource.split("\n");
            sourceColumns = sourceLines[sourceLines.length-1];
        }

        lines = chunk.split("\n");
        columns = lines[lines.length-1];

        if (fileInfo) {
            if (!mapLines) {
                this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + 1, column: this._column},
                    original: { line: sourceLines.length, column: sourceColumns.length},
                    source: this.normalizeFilename(fileInfo.filename)});
            } else {
                for(i = 0; i < lines.length; i++) {
                    this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + i + 1, column: i === 0 ? this._column : 0},
                        original: { line: sourceLines.length + i, column: i === 0 ? sourceColumns.length : 0},
                        source: this.normalizeFilename(fileInfo.filename)});
                }
            }
        }

        if (lines.length === 1) {
            this._column += columns.length;
        } else {
            this._lineNumber += lines.length - 1;
            this._column = columns.length;
        }

        this._css.push(chunk);
    };

    tree.sourceMapOutput.prototype.isEmpty = function() {
        return this._css.length === 0;
    };

    tree.sourceMapOutput.prototype.toCSS = function(env) {
        this._sourceMapGenerator = new this._sourceMapGeneratorConstructor({ file: this._outputFilename, sourceRoot: null });

        if (this._outputSourceFiles) {
            for(var filename in this._contentsMap) {
                var source = this._contentsMap[filename];
                if (this._contentsIgnoredCharsMap[filename]) {
                    source = source.slice(this._contentsIgnoredCharsMap[filename]);
                }
                this._sourceMapGenerator.setSourceContent(this.normalizeFilename(filename), source);
            }
        }

        this._rootNode.genCSS(env, this);

        if (this._css.length > 0) {
            var sourceMapURL,
                sourceMapContent = JSON.stringify(this._sourceMapGenerator.toJSON());

            if (this._sourceMapURL) {
                sourceMapURL = this._sourceMapURL;
            } else if (this._sourceMapFilename) {
                sourceMapURL = this.normalizeFilename(this._sourceMapFilename);
            }

            if (this._writeSourceMap) {
                this._writeSourceMap(sourceMapContent);
            } else {
                sourceMapURL = "data:application/json," + encodeURIComponent(sourceMapContent);
            }

            if (sourceMapURL) {
                this._css.push("/*# sourceMappingURL=" + sourceMapURL + " */");
            }
        }

        return this._css.join('');
    };

})(require('./tree'));

//
// browser.js - client-side engine
//
/*global less, window, document, XMLHttpRequest, location */

var isFileProtocol = /^(file|chrome(-extension)?|resource|qrc|app):/.test(location.protocol);

less.env = less.env || (location.hostname == '127.0.0.1' ||
                        location.hostname == '0.0.0.0'   ||
                        location.hostname == 'localhost' ||
                        (location.port &&
                          location.port.length > 0)      ||
                        isFileProtocol                   ? 'development'
                                                         : 'production');

var logLevel = {
    info: 2,
    errors: 1,
    none: 0
};

// The amount of logging in the javascript console.
// 2 - Information and errors
// 1 - Errors
// 0 - None
// Defaults to 2
less.logLevel = typeof(less.logLevel) != 'undefined' ? less.logLevel : logLevel.info;

// Load styles asynchronously (default: false)
//
// This is set to `false` by default, so that the body
// doesn't start loading before the stylesheets are parsed.
// Setting this to `true` can result in flickering.
//
less.async = less.async || false;
less.fileAsync = less.fileAsync || false;

// Interval between watch polls
less.poll = less.poll || (isFileProtocol ? 1000 : 1500);

//Setup user functions
if (less.functions) {
    for(var func in less.functions) {
        less.tree.functions[func] = less.functions[func];
   }
}

var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(location.hash);
if (dumpLineNumbers) {
    less.dumpLineNumbers = dumpLineNumbers[1];
}

var typePattern = /^text\/(x-)?less$/;
var cache = null;
var fileCache = {};

function log(str, level) {
    if (less.env == 'development' && typeof(console) !== 'undefined' && less.logLevel >= level) {
        console.log('less: ' + str);
    }
}

function extractId(href) {
    return href.replace(/^[a-z-]+:\/+?[^\/]+/, '' )  // Remove protocol & domain
        .replace(/^\//,                 '' )  // Remove root /
        .replace(/\.[a-zA-Z]+$/,        '' )  // Remove simple extension
        .replace(/[^\.\w-]+/g,          '-')  // Replace illegal characters
        .replace(/\./g,                 ':'); // Replace dots with colons(for valid id)
}

function errorConsole(e, rootHref) {
    var template = '{line} {content}';
    var filename = e.filename || rootHref;
    var errors = [];
    var content = (e.type || "Syntax") + "Error: " + (e.message || 'There is an error in your .less file') +
        " in " + filename + " ";

    var errorline = function (e, i, classname) {
        if (e.extract[i] !== undefined) {
            errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                .replace(/\{class\}/, classname)
                .replace(/\{content\}/, e.extract[i]));
        }
    };

    if (e.extract) {
        errorline(e, 0, '');
        errorline(e, 1, 'line');
        errorline(e, 2, '');
        content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':\n' +
            errors.join('\n');
    } else if (e.stack) {
        content += e.stack;
    }
    log(content, logLevel.errors);
}

function createCSS(styles, sheet, lastModified) {
    // Strip the query-string
    var href = sheet.href || '';

    // If there is no title set, use the filename, minus the extension
    var id = 'less:' + (sheet.title || extractId(href));

    // If this has already been inserted into the DOM, we may need to replace it
    var oldCss = document.getElementById(id);
    var keepOldCss = false;

    // Create a new stylesheet node for insertion or (if necessary) replacement
    var css = document.createElement('style');
    css.setAttribute('type', 'text/css');
    if (sheet.media) {
        css.setAttribute('media', sheet.media);
    }
    css.id = id;

    if (css.styleSheet) { // IE
        try {
            css.styleSheet.cssText = styles;
        } catch (e) {
            throw new(Error)("Couldn't reassign styleSheet.cssText.");
        }
    } else {
        css.appendChild(document.createTextNode(styles));

        // If new contents match contents of oldCss, don't replace oldCss
        keepOldCss = (oldCss !== null && oldCss.childNodes.length > 0 && css.childNodes.length > 0 &&
            oldCss.firstChild.nodeValue === css.firstChild.nodeValue);
    }

    var head = document.getElementsByTagName('head')[0];

    // If there is no oldCss, just append; otherwise, only append if we need
    // to replace oldCss with an updated stylesheet
    if (oldCss === null || keepOldCss === false) {
        var nextEl = sheet && sheet.nextSibling || null;
        if (nextEl) {
            nextEl.parentNode.insertBefore(css, nextEl);
        } else {
            head.appendChild(css);
        }
    }
    if (oldCss && keepOldCss === false) {
        oldCss.parentNode.removeChild(oldCss);
    }

    // Don't update the local store if the file wasn't modified
    if (lastModified && cache) {
        log('saving ' + href + ' to cache.', logLevel.info);
        try {
            cache.setItem(href, styles);
            cache.setItem(href + ':timestamp', lastModified);
        } catch(e) {
            //TODO - could do with adding more robust error handling
            log('failed to save', logLevel.errors);
        }
    }
}

function errorHTML(e, rootHref) {
    var id = 'less-error-message:' + extractId(rootHref || "");
    var template = '<li><label>{line}</label><pre class="{class}">{content}</pre></li>';
    var elem = document.createElement('div'), timer, content, errors = [];
    var filename = e.filename || rootHref;
    var filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];

    elem.id        = id;
    elem.className = "less-error-message";

    content = '<h3>'  + (e.type || "Syntax") + "Error: " + (e.message || 'There is an error in your .less file') +
        '</h3>' + '<p>in <a href="' + filename   + '">' + filenameNoPath + "</a> ";

    var errorline = function (e, i, classname) {
        if (e.extract[i] !== undefined) {
            errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                .replace(/\{class\}/, classname)
                .replace(/\{content\}/, e.extract[i]));
        }
    };

    if (e.extract) {
        errorline(e, 0, '');
        errorline(e, 1, 'line');
        errorline(e, 2, '');
        content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':</p>' +
            '<ul>' + errors.join('') + '</ul>';
    } else if (e.stack) {
        content += '<br/>' + e.stack.split('\n').slice(1).join('<br/>');
    }
    elem.innerHTML = content;

    // CSS for error messages
    createCSS([
        '.less-error-message ul, .less-error-message li {',
        'list-style-type: none;',
        'margin-right: 15px;',
        'padding: 4px 0;',
        'margin: 0;',
        '}',
        '.less-error-message label {',
        'font-size: 12px;',
        'margin-right: 15px;',
        'padding: 4px 0;',
        'color: #cc7777;',
        '}',
        '.less-error-message pre {',
        'color: #dd6666;',
        'padding: 4px 0;',
        'margin: 0;',
        'display: inline-block;',
        '}',
        '.less-error-message pre.line {',
        'color: #ff0000;',
        '}',
        '.less-error-message h3 {',
        'font-size: 20px;',
        'font-weight: bold;',
        'padding: 15px 0 5px 0;',
        'margin: 0;',
        '}',
        '.less-error-message a {',
        'color: #10a',
        '}',
        '.less-error-message .error {',
        'color: red;',
        'font-weight: bold;',
        'padding-bottom: 2px;',
        'border-bottom: 1px dashed red;',
        '}'
    ].join('\n'), { title: 'error-message' });

    elem.style.cssText = [
        "font-family: Arial, sans-serif",
        "border: 1px solid #e00",
        "background-color: #eee",
        "border-radius: 5px",
        "-webkit-border-radius: 5px",
        "-moz-border-radius: 5px",
        "color: #e00",
        "padding: 15px",
        "margin-bottom: 15px"
    ].join(';');

    if (less.env == 'development') {
        timer = setInterval(function () {
            if (document.body) {
                if (document.getElementById(id)) {
                    document.body.replaceChild(elem, document.getElementById(id));
                } else {
                    document.body.insertBefore(elem, document.body.firstChild);
                }
                clearInterval(timer);
            }
        }, 10);
    }
}

function error(e, rootHref) {
    if (!less.errorReporting || less.errorReporting === "html") {
        errorHTML(e, rootHref);
    } else if (less.errorReporting === "console") {
        errorConsole(e, rootHref);
    } else if (typeof less.errorReporting === 'function') {
        less.errorReporting("add", e, rootHref);
    }
}

function removeErrorHTML(path) {
    var node = document.getElementById('less-error-message:' + extractId(path));
    if (node) {
        node.parentNode.removeChild(node);
    }
}

function removeErrorConsole(path) {
    //no action
}

function removeError(path) {
    if (!less.errorReporting || less.errorReporting === "html") {
        removeErrorHTML(path);
    } else if (less.errorReporting === "console") {
        removeErrorConsole(path);
    } else if (typeof less.errorReporting === 'function') {
        less.errorReporting("remove", path);
    }
}

function loadStyles(modifyVars) {
    var styles = document.getElementsByTagName('style'),
        style;
    for (var i = 0; i < styles.length; i++) {
        style = styles[i];
        if (style.type.match(typePattern)) {
            var env = new less.tree.parseEnv(less),
                lessText = style.innerHTML || '';
            env.filename = document.location.href.replace(/#.*$/, '');

            if (modifyVars || less.globalVars) {
                env.useFileCache = true;
            }

            /*jshint loopfunc:true */
            // use closure to store current value of i
            var callback = (function(style) {
                return function (e, cssAST) {
                    if (e) {
                        return error(e, "inline");
                    }
                    var css = cssAST.toCSS(less);
                    style.type = 'text/css';
                    if (style.styleSheet) {
                        style.styleSheet.cssText = css;
                    } else {
                        style.innerHTML = css;
                    }
                };
            })(style);
            new(less.Parser)(env).parse(lessText, callback, {globalVars: less.globalVars, modifyVars: modifyVars});
        }
    }
}

function extractUrlParts(url, baseUrl) {
    // urlParts[1] = protocol&hostname || /
    // urlParts[2] = / if path relative to host base
    // urlParts[3] = directories
    // urlParts[4] = filename
    // urlParts[5] = parameters

    var urlPartsRegex = /^((?:[a-z-]+:)?\/+?(?:[^\/\?#]*\/)|([\/\\]))?((?:[^\/\\\?#]*[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/i,
        urlParts = url.match(urlPartsRegex),
        returner = {}, directories = [], i, baseUrlParts;

    if (!urlParts) {
        throw new Error("Could not parse sheet href - '"+url+"'");
    }

    // Stylesheets in IE don't always return the full path
    if (!urlParts[1] || urlParts[2]) {
        baseUrlParts = baseUrl.match(urlPartsRegex);
        if (!baseUrlParts) {
            throw new Error("Could not parse page url - '"+baseUrl+"'");
        }
        urlParts[1] = urlParts[1] || baseUrlParts[1] || "";
        if (!urlParts[2]) {
            urlParts[3] = baseUrlParts[3] + urlParts[3];
        }
    }

    if (urlParts[3]) {
        directories = urlParts[3].replace(/\\/g, "/").split("/");

        // extract out . before .. so .. doesn't absorb a non-directory
        for(i = 0; i < directories.length; i++) {
            if (directories[i] === ".") {
                directories.splice(i, 1);
                i -= 1;
            }
        }

        for(i = 0; i < directories.length; i++) {
            if (directories[i] === ".." && i > 0) {
                directories.splice(i-1, 2);
                i -= 2;
            }
        }
    }

    returner.hostPart = urlParts[1];
    returner.directories = directories;
    returner.path = urlParts[1] + directories.join("/");
    returner.fileUrl = returner.path + (urlParts[4] || "");
    returner.url = returner.fileUrl + (urlParts[5] || "");
    return returner;
}

function pathDiff(url, baseUrl) {
    // diff between two paths to create a relative path

    var urlParts = extractUrlParts(url),
        baseUrlParts = extractUrlParts(baseUrl),
        i, max, urlDirectories, baseUrlDirectories, diff = "";
    if (urlParts.hostPart !== baseUrlParts.hostPart) {
        return "";
    }
    max = Math.max(baseUrlParts.directories.length, urlParts.directories.length);
    for(i = 0; i < max; i++) {
        if (baseUrlParts.directories[i] !== urlParts.directories[i]) { break; }
    }
    baseUrlDirectories = baseUrlParts.directories.slice(i);
    urlDirectories = urlParts.directories.slice(i);
    for(i = 0; i < baseUrlDirectories.length-1; i++) {
        diff += "../";
    }
    for(i = 0; i < urlDirectories.length-1; i++) {
        diff += urlDirectories[i] + "/";
    }
    return diff;
}

function getXMLHttpRequest() {
    if (window.XMLHttpRequest) {
        return new XMLHttpRequest();
    } else {
        try {
            /*global ActiveXObject */
            return new ActiveXObject("MSXML2.XMLHTTP.3.0");
        } catch (e) {
            log("browser doesn't support AJAX.", logLevel.errors);
            return null;
        }
    }
}

function doXHR(url, type, callback, errback) {
    var xhr = getXMLHttpRequest();
    var async = isFileProtocol ? less.fileAsync : less.async;

    if (typeof(xhr.overrideMimeType) === 'function') {
        xhr.overrideMimeType('text/css');
    }
    log("XHR: Getting '" + url + "'", logLevel.info);
    xhr.open('GET', url, async);
    xhr.setRequestHeader('Accept', type || 'text/x-less, text/css; q=0.9, */*; q=0.5');
    xhr.send(null);

    function handleResponse(xhr, callback, errback) {
        if (xhr.status >= 200 && xhr.status < 300) {
            callback(xhr.responseText,
                xhr.getResponseHeader("Last-Modified"));
        } else if (typeof(errback) === 'function') {
            errback(xhr.status, url);
        }
    }

    if (isFileProtocol && !less.fileAsync) {
        if (xhr.status === 0 || (xhr.status >= 200 && xhr.status < 300)) {
            callback(xhr.responseText);
        } else {
            errback(xhr.status, url);
        }
    } else if (async) {
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4) {
                handleResponse(xhr, callback, errback);
            }
        };
    } else {
        handleResponse(xhr, callback, errback);
    }
}

function loadFile(originalHref, currentFileInfo, callback, env, modifyVars) {

    if (currentFileInfo && currentFileInfo.currentDirectory && !/^([a-z-]+:)?\//.test(originalHref)) {
        originalHref = currentFileInfo.currentDirectory + originalHref;
    }

    // sheet may be set to the stylesheet for the initial load or a collection of properties including
    // some env variables for imports
    var hrefParts = extractUrlParts(originalHref, window.location.href);
    var href      = hrefParts.url;
    var newFileInfo = {
        currentDirectory: hrefParts.path,
        filename: href
    };

    if (currentFileInfo) {
        newFileInfo.entryPath = currentFileInfo.entryPath;
        newFileInfo.rootpath = currentFileInfo.rootpath;
        newFileInfo.rootFilename = currentFileInfo.rootFilename;
        newFileInfo.relativeUrls = currentFileInfo.relativeUrls;
    } else {
        newFileInfo.entryPath = hrefParts.path;
        newFileInfo.rootpath = less.rootpath || hrefParts.path;
        newFileInfo.rootFilename = href;
        newFileInfo.relativeUrls = env.relativeUrls;
    }

    if (newFileInfo.relativeUrls) {
        if (env.rootpath) {
            newFileInfo.rootpath = extractUrlParts(env.rootpath + pathDiff(hrefParts.path, newFileInfo.entryPath)).path;
        } else {
            newFileInfo.rootpath = hrefParts.path;
        }
    }

    if (env.useFileCache && fileCache[href]) {
        try {
            var lessText = fileCache[href];
            callback(null, lessText, href, newFileInfo, { lastModified: new Date() });
        } catch (e) {
            callback(e, null, href);
        }
        return;
    }

    doXHR(href, env.mime, function (data, lastModified) {
        // per file cache
        fileCache[href] = data;

        // Use remote copy (re-parse)
        try {
            callback(null, data, href, newFileInfo, { lastModified: lastModified });
        } catch (e) {
            callback(e, null, href);
        }
    }, function (status, url) {
        callback({ type: 'File', message: "'" + url + "' wasn't found (" + status + ")" }, null, href);
    });
}

function loadStyleSheet(sheet, callback, reload, remaining, modifyVars) {

    var env = new less.tree.parseEnv(less);
    env.mime = sheet.type;

    if (modifyVars || less.globalVars) {
        env.useFileCache = true;
    }

    loadFile(sheet.href, null, function(e, data, path, newFileInfo, webInfo) {

        if (webInfo) {
            webInfo.remaining = remaining;

            var css       = cache && cache.getItem(path),
                timestamp = cache && cache.getItem(path + ':timestamp');

            if (!reload && timestamp && webInfo.lastModified &&
                (new(Date)(webInfo.lastModified).valueOf() ===
                    new(Date)(timestamp).valueOf())) {
                // Use local copy
                createCSS(css, sheet);
                webInfo.local = true;
                callback(null, null, data, sheet, webInfo, path);
                return;
            }
        }

        //TODO add tests around how this behaves when reloading
        removeError(path);

        if (data) {
            env.currentFileInfo = newFileInfo;
            new(less.Parser)(env).parse(data, function (e, root) {
                if (e) { return callback(e, null, null, sheet); }
                try {
                    callback(e, root, data, sheet, webInfo, path);
                } catch (e) {
                    callback(e, null, null, sheet);
                }
            }, {modifyVars: modifyVars, globalVars: less.globalVars});
        } else {
            callback(e, null, null, sheet, webInfo, path);
        }
    }, env, modifyVars);
}

function loadStyleSheets(callback, reload, modifyVars) {
    for (var i = 0; i < less.sheets.length; i++) {
        loadStyleSheet(less.sheets[i], callback, reload, less.sheets.length - (i + 1), modifyVars);
    }
}

function initRunningMode(){
    if (less.env === 'development') {
        less.optimization = 0;
        less.watchTimer = setInterval(function () {
            if (less.watchMode) {
                loadStyleSheets(function (e, root, _, sheet, env) {
                    if (e) {
                        error(e, sheet.href);
                    } else if (root) {
                        createCSS(root.toCSS(less), sheet, env.lastModified);
                    }
                });
            }
        }, less.poll);
    } else {
        less.optimization = 3;
    }
}



//
// Watch mode
//
less.watch   = function () {
    if (!less.watchMode ){
        less.env = 'development';
         initRunningMode();
    }
    this.watchMode = true;
    return true;
};

less.unwatch = function () {clearInterval(less.watchTimer); this.watchMode = false; return false; };

if (/!watch/.test(location.hash)) {
    less.watch();
}

if (less.env != 'development') {
    try {
        cache = (typeof(window.localStorage) === 'undefined') ? null : window.localStorage;
    } catch (_) {}
}

//
// Get all <link> tags with the 'rel' attribute set to "stylesheet/less"
//
var links = document.getElementsByTagName('link');

less.sheets = [];

for (var i = 0; i < links.length; i++) {
    if (links[i].rel === 'stylesheet/less' || (links[i].rel.match(/stylesheet/) &&
       (links[i].type.match(typePattern)))) {
        less.sheets.push(links[i]);
    }
}

//
// With this function, it's possible to alter variables and re-render
// CSS without reloading less-files
//
less.modifyVars = function(record) {
    less.refresh(false, record);
};

less.refresh = function (reload, modifyVars) {
    var startTime, endTime;
    startTime = endTime = new Date();

    loadStyleSheets(function (e, root, _, sheet, env) {
        if (e) {
            return error(e, sheet.href);
        }
        if (env.local) {
            log("loading " + sheet.href + " from cache.", logLevel.info);
        } else {
            log("parsed " + sheet.href + " successfully.", logLevel.info);
            createCSS(root.toCSS(less), sheet, env.lastModified);
        }
        log("css for " + sheet.href + " generated in " + (new Date() - endTime) + 'ms', logLevel.info);
        if (env.remaining === 0) {
            log("css generated in " + (new Date() - startTime) + 'ms', logLevel.info);
        }
        endTime = new Date();
    }, reload, modifyVars);

    loadStyles(modifyVars);
};

less.refreshStyles = loadStyles;

less.Parser.fileLoader = loadFile;

less.refresh(less.env === 'development');

// amd.js
//
// Define Less as an AMD module.
if (typeof define === "function" && define.amd) {
    define(function () { return less; } );
}

})(window);
;!function(exports, undefined) {

  var isArray = Array.isArray ? Array.isArray : function _isArray(obj) {
    return Object.prototype.toString.call(obj) === "[object Array]";
  };
  var defaultMaxListeners = 10;

  function init() {
    this._events = {};
    if (this._conf) {
      configure.call(this, this._conf);
    }
  }

  function configure(conf) {
    if (conf) {

      this._conf = conf;

      conf.delimiter && (this.delimiter = conf.delimiter);
      conf.maxListeners && (this._events.maxListeners = conf.maxListeners);
      conf.wildcard && (this.wildcard = conf.wildcard);
      conf.newListener && (this.newListener = conf.newListener);

      if (this.wildcard) {
        this.listenerTree = {};
      }
    }
  }

  function EventEmitter(conf) {
    this._events = {};
    this.newListener = false;
    configure.call(this, conf);
  }

  //
  // Attention, function return type now is array, always !
  // It has zero elements if no any matches found and one or more
  // elements (leafs) if there are matches
  //
  function searchListenerTree(handlers, type, tree, i) {
    if (!tree) {
      return [];
    }
    var listeners=[], leaf, len, branch, xTree, xxTree, isolatedBranch, endReached,
        typeLength = type.length, currentType = type[i], nextType = type[i+1];
    if (i === typeLength && tree._listeners) {
      //
      // If at the end of the event(s) list and the tree has listeners
      // invoke those listeners.
      //
      if (typeof tree._listeners === 'function') {
        handlers && handlers.push(tree._listeners);
        return [tree];
      } else {
        for (leaf = 0, len = tree._listeners.length; leaf < len; leaf++) {
          handlers && handlers.push(tree._listeners[leaf]);
        }
        return [tree];
      }
    }

    if ((currentType === '*' || currentType === '**') || tree[currentType]) {
      //
      // If the event emitted is '*' at this part
      // or there is a concrete match at this patch
      //
      if (currentType === '*') {
        for (branch in tree) {
          if (branch !== '_listeners' && tree.hasOwnProperty(branch)) {
            listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i+1));
          }
        }
        return listeners;
      } else if(currentType === '**') {
        endReached = (i+1 === typeLength || (i+2 === typeLength && nextType === '*'));
        if(endReached && tree._listeners) {
          // The next element has a _listeners, add it to the handlers.
          listeners = listeners.concat(searchListenerTree(handlers, type, tree, typeLength));
        }

        for (branch in tree) {
          if (branch !== '_listeners' && tree.hasOwnProperty(branch)) {
            if(branch === '*' || branch === '**') {
              if(tree[branch]._listeners && !endReached) {
                listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], typeLength));
              }
              listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i));
            } else if(branch === nextType) {
              listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i+2));
            } else {
              // No match on this one, shift into the tree but not in the type array.
              listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i));
            }
          }
        }
        return listeners;
      }

      listeners = listeners.concat(searchListenerTree(handlers, type, tree[currentType], i+1));
    }

    xTree = tree['*'];
    if (xTree) {
      //
      // If the listener tree will allow any match for this part,
      // then recursively explore all branches of the tree
      //
      searchListenerTree(handlers, type, xTree, i+1);
    }

    xxTree = tree['**'];
    if(xxTree) {
      if(i < typeLength) {
        if(xxTree._listeners) {
          // If we have a listener on a '**', it will catch all, so add its handler.
          searchListenerTree(handlers, type, xxTree, typeLength);
        }

        // Build arrays of matching next branches and others.
        for(branch in xxTree) {
          if(branch !== '_listeners' && xxTree.hasOwnProperty(branch)) {
            if(branch === nextType) {
              // We know the next element will match, so jump twice.
              searchListenerTree(handlers, type, xxTree[branch], i+2);
            } else if(branch === currentType) {
              // Current node matches, move into the tree.
              searchListenerTree(handlers, type, xxTree[branch], i+1);
            } else {
              isolatedBranch = {};
              isolatedBranch[branch] = xxTree[branch];
              searchListenerTree(handlers, type, { '**': isolatedBranch }, i+1);
            }
          }
        }
      } else if(xxTree._listeners) {
        // We have reached the end and still on a '**'
        searchListenerTree(handlers, type, xxTree, typeLength);
      } else if(xxTree['*'] && xxTree['*']._listeners) {
        searchListenerTree(handlers, type, xxTree['*'], typeLength);
      }
    }

    return listeners;
  }

  function growListenerTree(type, listener) {

    type = typeof type === 'string' ? type.split(this.delimiter) : type.slice();

    //
    // Looks for two consecutive '**', if so, don't add the event at all.
    //
    for(var i = 0, len = type.length; i+1 < len; i++) {
      if(type[i] === '**' && type[i+1] === '**') {
        return;
      }
    }

    var tree = this.listenerTree;
    var name = type.shift();

    while (name) {

      if (!tree[name]) {
        tree[name] = {};
      }

      tree = tree[name];

      if (type.length === 0) {

        if (!tree._listeners) {
          tree._listeners = listener;
        }
        else if(typeof tree._listeners === 'function') {
          tree._listeners = [tree._listeners, listener];
        }
        else if (isArray(tree._listeners)) {

          tree._listeners.push(listener);

          if (!tree._listeners.warned) {

            var m = defaultMaxListeners;

            if (typeof this._events.maxListeners !== 'undefined') {
              m = this._events.maxListeners;
            }

            if (m > 0 && tree._listeners.length > m) {

              tree._listeners.warned = true;
              console.error('(node) warning: possible EventEmitter memory ' +
                            'leak detected. %d listeners added. ' +
                            'Use emitter.setMaxListeners() to increase limit.',
                            tree._listeners.length);
              console.trace();
            }
          }
        }
        return true;
      }
      name = type.shift();
    }
    return true;
  }

  // By default EventEmitters will print a warning if more than
  // 10 listeners are added to it. This is a useful default which
  // helps finding memory leaks.
  //
  // Obviously not all Emitters should be limited to 10. This function allows
  // that to be increased. Set to zero for unlimited.

  EventEmitter.prototype.delimiter = '.';

  EventEmitter.prototype.setMaxListeners = function(n) {
    this._events || init.call(this);
    this._events.maxListeners = n;
    if (!this._conf) this._conf = {};
    this._conf.maxListeners = n;
  };

  EventEmitter.prototype.event = '';

  EventEmitter.prototype.once = function(event, fn) {
    this.many(event, 1, fn);
    return this;
  };

  EventEmitter.prototype.many = function(event, ttl, fn) {
    var self = this;

    if (typeof fn !== 'function') {
      throw new Error('many only accepts instances of Function');
    }

    function listener() {
      if (--ttl === 0) {
        self.off(event, listener);
      }
      fn.apply(this, arguments);
    }

    listener._origin = fn;

    this.on(event, listener);

    return self;
  };

  EventEmitter.prototype.emit = function() {

    this._events || init.call(this);

    var type = arguments[0];

    if (type === 'newListener' && !this.newListener) {
      if (!this._events.newListener) { return false; }
    }

    // Loop through the *_all* functions and invoke them.
    if (this._all) {
      var l = arguments.length;
      var args = new Array(l - 1);
      for (var i = 1; i < l; i++) args[i - 1] = arguments[i];
      for (i = 0, l = this._all.length; i < l; i++) {
        this.event = type;
        this._all[i].apply(this, args);
      }
    }

    // If there is no 'error' event listener then throw.
    if (type === 'error') {

      if (!this._all &&
        !this._events.error &&
        !(this.wildcard && this.listenerTree.error)) {

        if (arguments[1] instanceof Error) {
          throw arguments[1]; // Unhandled 'error' event
        } else {
          throw new Error("Uncaught, unspecified 'error' event.");
        }
        return false;
      }
    }

    var handler;

    if(this.wildcard) {
      handler = [];
      var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
      searchListenerTree.call(this, handler, ns, this.listenerTree, 0);
    }
    else {
      handler = this._events[type];
    }

    if (typeof handler === 'function') {
      this.event = type;
      if (arguments.length === 1) {
        handler.call(this);
      }
      else if (arguments.length > 1)
        switch (arguments.length) {
          case 2:
            handler.call(this, arguments[1]);
            break;
          case 3:
            handler.call(this, arguments[1], arguments[2]);
            break;
          // slower
          default:
            var l = arguments.length;
            var args = new Array(l - 1);
            for (var i = 1; i < l; i++) args[i - 1] = arguments[i];
            handler.apply(this, args);
        }
      return true;
    }
    else if (handler) {
      var l = arguments.length;
      var args = new Array(l - 1);
      for (var i = 1; i < l; i++) args[i - 1] = arguments[i];

      var listeners = handler.slice();
      for (var i = 0, l = listeners.length; i < l; i++) {
        this.event = type;
        listeners[i].apply(this, args);
      }
      return (listeners.length > 0) || this._all;
    }
    else {
      return this._all;
    }

  };

  EventEmitter.prototype.on = function(type, listener) {

    if (typeof type === 'function') {
      this.onAny(type);
      return this;
    }

    if (typeof listener !== 'function') {
      throw new Error('on only accepts instances of Function');
    }
    this._events || init.call(this);

    // To avoid recursion in the case that type == "newListeners"! Before
    // adding it to the listeners, first emit "newListeners".
    this.emit('newListener', type, listener);

    if(this.wildcard) {
      growListenerTree.call(this, type, listener);
      return this;
    }

    if (!this._events[type]) {
      // Optimize the case of one listener. Don't need the extra array object.
      this._events[type] = listener;
    }
    else if(typeof this._events[type] === 'function') {
      // Adding the second element, need to change to array.
      this._events[type] = [this._events[type], listener];
    }
    else if (isArray(this._events[type])) {
      // If we've already got an array, just append.
      this._events[type].push(listener);

      // Check for listener leak
      if (!this._events[type].warned) {

        var m = defaultMaxListeners;

        if (typeof this._events.maxListeners !== 'undefined') {
          m = this._events.maxListeners;
        }

        if (m > 0 && this._events[type].length > m) {

          this._events[type].warned = true;
          console.error('(node) warning: possible EventEmitter memory ' +
                        'leak detected. %d listeners added. ' +
                        'Use emitter.setMaxListeners() to increase limit.',
                        this._events[type].length);
          console.trace();
        }
      }
    }
    return this;
  };

  EventEmitter.prototype.onAny = function(fn) {

    if(!this._all) {
      this._all = [];
    }

    if (typeof fn !== 'function') {
      throw new Error('onAny only accepts instances of Function');
    }

    // Add the function to the event listener collection.
    this._all.push(fn);
    return this;
  };

  EventEmitter.prototype.addListener = EventEmitter.prototype.on;

  EventEmitter.prototype.off = function(type, listener) {
    if (typeof listener !== 'function') {
      throw new Error('removeListener only takes instances of Function');
    }

    var handlers,leafs=[];

    if(this.wildcard) {
      var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
      leafs = searchListenerTree.call(this, null, ns, this.listenerTree, 0);
    }
    else {
      // does not use listeners(), so no side effect of creating _events[type]
      if (!this._events[type]) return this;
      handlers = this._events[type];
      leafs.push({_listeners:handlers});
    }

    for (var iLeaf=0; iLeaf<leafs.length; iLeaf++) {
      var leaf = leafs[iLeaf];
      handlers = leaf._listeners;
      if (isArray(handlers)) {

        var position = -1;

        for (var i = 0, length = handlers.length; i < length; i++) {
          if (handlers[i] === listener ||
            (handlers[i].listener && handlers[i].listener === listener) ||
            (handlers[i]._origin && handlers[i]._origin === listener)) {
            position = i;
            break;
          }
        }

        if (position < 0) {
          continue;
        }

        if(this.wildcard) {
          leaf._listeners.splice(position, 1);
        }
        else {
          this._events[type].splice(position, 1);
        }

        if (handlers.length === 0) {
          if(this.wildcard) {
            delete leaf._listeners;
          }
          else {
            delete this._events[type];
          }
        }
        return this;
      }
      else if (handlers === listener ||
        (handlers.listener && handlers.listener === listener) ||
        (handlers._origin && handlers._origin === listener)) {
        if(this.wildcard) {
          delete leaf._listeners;
        }
        else {
          delete this._events[type];
        }
      }
    }

    return this;
  };

  EventEmitter.prototype.offAny = function(fn) {
    var i = 0, l = 0, fns;
    if (fn && this._all && this._all.length > 0) {
      fns = this._all;
      for(i = 0, l = fns.length; i < l; i++) {
        if(fn === fns[i]) {
          fns.splice(i, 1);
          return this;
        }
      }
    } else {
      this._all = [];
    }
    return this;
  };

  EventEmitter.prototype.removeListener = EventEmitter.prototype.off;

  EventEmitter.prototype.removeAllListeners = function(type) {
    if (arguments.length === 0) {
      !this._events || init.call(this);
      return this;
    }

    if(this.wildcard) {
      var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
      var leafs = searchListenerTree.call(this, null, ns, this.listenerTree, 0);

      for (var iLeaf=0; iLeaf<leafs.length; iLeaf++) {
        var leaf = leafs[iLeaf];
        leaf._listeners = null;
      }
    }
    else {
      if (!this._events[type]) return this;
      this._events[type] = null;
    }
    return this;
  };

  EventEmitter.prototype.listeners = function(type) {
    if(this.wildcard) {
      var handlers = [];
      var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
      searchListenerTree.call(this, handlers, ns, this.listenerTree, 0);
      return handlers;
    }

    this._events || init.call(this);

    if (!this._events[type]) this._events[type] = [];
    if (!isArray(this._events[type])) {
      this._events[type] = [this._events[type]];
    }
    return this._events[type];
  };

  EventEmitter.prototype.listenersAny = function() {

    if(this._all) {
      return this._all;
    }
    else {
      return [];
    }

  };

  if (typeof define === 'function' && define.amd) {
    define(function() {
      return EventEmitter;
    });
  } else {
    exports.EventEmitter2 = EventEmitter;
  }

}(typeof process !== 'undefined' && typeof process.title !== 'undefined' && typeof exports !== 'undefined' ? exports : window);

(function(window) {
  'use strict';

  // Public: Create a new SelectorSet.
  function SelectorSet() {
    // Construct new SelectorSet if called as a function.
    if (!(this instanceof SelectorSet)) {
      return new SelectorSet();
    }

    // Public: Number of selectors added to the set
    this.size = 0;

    // Internal: Incrementing ID counter
    this.uid = 0;

    // Internal: Array of String selectors in the set
    this.selectors = [];

    // Internal: All Object index String names mapping to Index objects.
    this.indexes = Object.create(this.indexes);

    // Internal: Used Object index String names mapping to Index objects.
    this.activeIndexes = [];
  }

  // Detect prefixed Element#matches function.
  var docElem = window.document.documentElement;
  var matches = (docElem.webkitMatchesSelector ||
                  docElem.mozMatchesSelector ||
                  docElem.oMatchesSelector ||
                  docElem.msMatchesSelector);

  // Public: Check if element matches selector.
  //
  // Maybe overridden with custom Element.matches function.
  //
  // el       - An Element
  // selector - String CSS selector
  //
  // Returns true or false.
  SelectorSet.prototype.matchesSelector = function(el, selector) {
    return matches.call(el, selector);
  };

  // Public: Find all elements in the context that match the selector.
  //
  // Maybe overridden with custom querySelectorAll function.
  //
  // selectors - String CSS selectors.
  // context   - Element context
  //
  // Returns non-live list of Elements.
  SelectorSet.prototype.querySelectorAll = function(selectors, context) {
    return context.querySelectorAll(selectors);
  };


  // Public: Array of indexes.
  //
  // name     - Unique String name
  // selector - Function that takes a String selector and returns a String key
  //            or undefined if it can't be used by the index.
  // element  - Function that takes an Element and returns an Array of String
  //            keys that point to indexed values.
  //
  SelectorSet.prototype.indexes = [];

  // Index by element id
  var idRe = /^#((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
  SelectorSet.prototype.indexes.push({
    name: 'ID',
    selector: function matchIdSelector(sel) {
      var m;
      if (m = sel.match(idRe)) {
        return m[0].slice(1);
      }
    },
    element: function getElementId(el) {
      if (el.id) {
        return [el.id];
      }
    }
  });

  // Index by all of its class names
  var classRe = /^\.((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
  SelectorSet.prototype.indexes.push({
    name: 'CLASS',
    selector: function matchClassSelector(sel) {
      var m;
      if (m = sel.match(classRe)) {
        return m[0].slice(1);
      }
    },
    element: function getElementClassNames(el) {
      var className = el.className;
      if (className) {
        if (typeof className === 'string') {
          return className.split(/\s/);
        } else if (typeof className === 'object' && 'baseVal' in className) {
          // className is a SVGAnimatedString
          // global SVGAnimatedString is not an exposed global in Opera 12
          return className.baseVal.split(/\s/);
        }
      }
    }
  });

  // Index by tag/node name: `DIV`, `FORM`, `A`
  var tagRe = /^((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
  SelectorSet.prototype.indexes.push({
    name: 'TAG',
    selector: function matchTagSelector(sel) {
      var m;
      if (m = sel.match(tagRe)) {
        return m[0].toUpperCase();
      }
    },
    element: function getElementTagName(el) {
      return [el.nodeName.toUpperCase()];
    }
  });

  // Default index just contains a single array of elements.
  SelectorSet.prototype.indexes['default'] = {
    name: 'UNIVERSAL',
    selector: function() {
      return true;
    },
    element: function() {
      return [true];
    }
  };


  // Use ES Maps when supported
  var Map;
  if (typeof window.Map === 'function') {
    Map = window.Map;
  } else {
    Map = (function() {
      function Map() {
        this.map = {};
      }
      Map.prototype.get = function(key) {
        return this.map[key + ' '];
      };
      Map.prototype.set = function(key, value) {
        this.map[key + ' '] = value;
      };
      return Map;
    })();
  }


  // Regexps adopted from Sizzle
  //   https://github.com/jquery/sizzle/blob/1.7/sizzle.js
  //
  var chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?((?:.|\r|\n)*)/g;

  // Internal: Get indexes for selector.
  //
  // selector - String CSS selector
  //
  // Returns Array of {index, key}.
  function parseSelectorIndexes(allIndexes, selector) {
    allIndexes = allIndexes.slice(0).concat(allIndexes['default']);

    var allIndexesLen = allIndexes.length,
        i, j, m, dup, rest = selector,
        key, index, indexes = [];

    do {
      chunker.exec('');
      if (m = chunker.exec(rest)) {
        rest = m[3];
        if (m[2] || !rest) {
          for (i = 0; i < allIndexesLen; i++) {
            index = allIndexes[i];
            if (key = index.selector(m[1])) {
              j = indexes.length;
              dup = false;
              while (j--) {
                if (indexes[j].index === index && indexes[j].key === key) {
                  dup = true;
                  break;
                }
              }
              if (!dup) {
                indexes.push({index: index, key: key});
              }
              break;
            }
          }
        }
      }
    } while (m);

    return indexes;
  }

  // Internal: Find first item in Array that is a prototype of `proto`.
  //
  // ary   - Array of objects
  // proto - Prototype of expected item in `ary`
  //
  // Returns object from `ary` if found. Otherwise returns undefined.
  function findByPrototype(ary, proto) {
    var i, len, item;
    for (i = 0, len = ary.length; i < len; i++) {
      item = ary[i];
      if (proto.isPrototypeOf(item)) {
        return item;
      }
    }
  }

  // Public: Log when added selector falls under the default index.
  //
  // This API should not be considered stable. May change between
  // minor versions.
  //
  // obj - {selector, data} Object
  //
  //   SelectorSet.prototype.logDefaultIndexUsed = function(obj) {
  //     console.warn(obj.selector, "could not be indexed");
  //   };
  //
  // Returns nothing.
  SelectorSet.prototype.logDefaultIndexUsed = function() {};

  // Public: Add selector to set.
  //
  // selector - String CSS selector
  // data     - Optional data Object (default: undefined)
  //
  // Returns nothing.
  SelectorSet.prototype.add = function(selector, data) {
    var obj, i, indexProto, key, index, objs,
        selectorIndexes, selectorIndex,
        indexes = this.activeIndexes,
        selectors = this.selectors;

    if (typeof selector !== 'string') {
      return;
    }

    obj = {
      id: this.uid++,
      selector: selector,
      data: data
    };

    selectorIndexes = parseSelectorIndexes(this.indexes, selector);
    for (i = 0; i < selectorIndexes.length; i++) {
      selectorIndex = selectorIndexes[i];
      key = selectorIndex.key;
      indexProto = selectorIndex.index;

      index = findByPrototype(indexes, indexProto);
      if (!index) {
        index = Object.create(indexProto);
        index.map = new Map();
        indexes.push(index);
      }

      if (indexProto === this.indexes['default']) {
        this.logDefaultIndexUsed(obj);
      }
      objs = index.map.get(key);
      if (!objs) {
        objs = [];
        index.map.set(key, objs);
      }
      objs.push(obj);
    }

    this.size++;
    selectors.push(selector);
  };

  // Public: Remove selector from set.
  //
  // selector - String CSS selector
  // data     - Optional data Object (default: undefined)
  //
  // Returns nothing.
  SelectorSet.prototype.remove = function(selector, data) {
    if (typeof selector !== 'string') {
      return;
    }

    var selectorIndexes, selectorIndex, i, j, k, selIndex, objs, obj;
    var indexes = this.activeIndexes;
    var removedIds = {};
    var removeAll = arguments.length === 1;

    selectorIndexes = parseSelectorIndexes(this.indexes, selector);
    for (i = 0; i < selectorIndexes.length; i++) {
      selectorIndex = selectorIndexes[i];

      j = indexes.length;
      while (j--) {
        selIndex = indexes[j];
        if (selectorIndex.index.isPrototypeOf(selIndex)) {
          objs = selIndex.map.get(selectorIndex.key);
          if (objs) {
            k = objs.length;
            while (k--) {
              obj = objs[k];
              if (obj.selector === selector && (removeAll || obj.data === data)) {
                objs.splice(k, 1);
                removedIds[obj.id] = true;
              }
            }
          }
          break;
        }
      }
    }

    this.size -= Object.keys(removedIds).length;
  };

  // Sort by id property handler.
  //
  // a - Selector obj.
  // b - Selector obj.
  //
  // Returns Number.
  function sortById(a, b) {
    return a.id - b.id;
  }

  // Public: Find all matching decendants of the context element.
  //
  // context - An Element
  //
  // Returns Array of {selector, data, elements} matches.
  SelectorSet.prototype.queryAll = function(context) {
    if (!this.selectors.length) {
      return [];
    }

    var matches = {}, results = [];
    var els = this.querySelectorAll(this.selectors.join(', '), context);

    var i, j, len, len2, el, m, match, obj;
    for (i = 0, len = els.length; i < len; i++) {
      el = els[i];
      m = this.matches(el);
      for (j = 0, len2 = m.length; j < len2; j++) {
        obj = m[j];
        if (!matches[obj.id]) {
          match = {
            id: obj.id,
            selector: obj.selector,
            data: obj.data,
            elements: []
          };
          matches[obj.id] = match;
          results.push(match);
        } else {
          match = matches[obj.id];
        }
        match.elements.push(el);
      }
    }

    return results.sort(sortById);
  };

  // Public: Match element against all selectors in set.
  //
  // el - An Element
  //
  // Returns Array of {selector, data} matches.
  SelectorSet.prototype.matches = function(el) {
    if (!el) {
      return [];
    }

    var i, j, k, len, len2, len3, index, keys, objs, obj, id;
    var indexes = this.activeIndexes, matchedIds = {}, matches = [];

    for (i = 0, len = indexes.length; i < len; i++) {
      index = indexes[i];
      keys = index.element(el);
      if (keys) {
        for (j = 0, len2 = keys.length; j < len2; j++) {
          if (objs = index.map.get(keys[j])) {
            for (k = 0, len3 = objs.length; k < len3; k++) {
              obj = objs[k];
              id = obj.id;
              if (!matchedIds[id] && this.matchesSelector(el, obj.selector)) {
                matchedIds[id] = true;
                matches.push(obj);
              }
            }
          }
        }
      }
    }

    return matches.sort(sortById);
  };

  // Public: Expose SelectorSet as a global on window.
  window.SelectorSet = SelectorSet;
})(window);

(function() {
  var MODULES;

  MODULES = {
    underscore: this._,
    sizzle: this.Sizzle,
    less: this.less,
    eventemitter2: this.EventEmitter2,
    'selector-set': this.SelectorSet
  };

  this._ = this.__polyfills_originalGlobals['underscore'];

  this.less = this.__polyfills_originalGlobals['less'];

  this.EventEmitter2 = this.__polyfills_originalGlobals['eventemitter2'];

  this.define = function(moduleName, deps, callback) {
    var args, depName, first, second, val;
    args = (function() {
      var _i, _len, _ref, _results;
      _results = [];
      for (_i = 0, _len = deps.length; _i < _len; _i++) {
        depName = deps[_i];
        _ref = depName.split('!'), first = _ref[0], second = _ref[1];
        depName = second || first;
        if (!MODULES[depName]) {
          throw new Error('Files are not concatenated based on their dependencies');
        }
        _results.push(MODULES[depName]);
      }
      return _results;
    })();
    val = callback.apply(this, args);
    MODULES[moduleName] = val;
    return val;
  };

}).call(this);

(function() {
  var __slice = [].slice;

  define('polyfill-path/selector-tree', [], function() {
    var CHUNKIFY, SelectorTree, chunker;
    chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?((?:.|\r|\n)*)/g;
    CHUNKIFY = function(selector) {
      var chunks, m, rest;
      rest = selector;
      chunks = [];
      while (true) {
        chunker.exec('');
        if (m = chunker.exec(rest)) {
          rest = m[3];
          chunks.push(m[1]);
          if (m[2] || !rest) {
            break;
          }
        }
        if (!m) {
          break;
        }
      }
      return chunks;
    };
    return SelectorTree = (function() {
      function SelectorTree(children, data) {
        this.children = children != null ? children : {};
        this.data = data != null ? data : [];
      }

      SelectorTree.prototype._add = function(chunks, datum) {
        var first, rest;
        if (chunks.length === 0) {
          return this.data.push(datum);
        } else {
          first = chunks[0], rest = 2 <= chunks.length ? __slice.call(chunks, 1) : [];
          if (!this.children[first]) {
            this.children[first] = new SelectorTree();
          }
          return this.children[first]._add(rest, datum);
        }
      };

      SelectorTree.prototype.clear = function() {
        this.children = {};
        return this.data = [];
      };

      SelectorTree.prototype.add = function(selector, datum) {
        var sel, selectors, _i, _len, _results;
        selectors = selector.split(',');
        _results = [];
        for (_i = 0, _len = selectors.length; _i < _len; _i++) {
          sel = selectors[_i];
          _results.push(this._add(CHUNKIFY(sel), datum));
        }
        return _results;
      };

      SelectorTree.prototype.findMatches = function(rootEl, acc, selectorFirst) {
        var els, selector, selectorSnippet, tree, _ref;
        if (acc == null) {
          acc = {};
        }
        if (selectorFirst == null) {
          selectorFirst = '';
        }
        _ref = this.children;
        for (selectorSnippet in _ref) {
          tree = _ref[selectorSnippet];
          selector = "" + selectorFirst + " " + selectorSnippet;
          if (tree.data.length > 0) {
            console.log("KLASDJFKLAJF Querying " + selector);
            els = rootEl.querySelectorAll(selector);
            acc[selector] = {
              els: els,
              data: tree.data
            };
          } else {
            tree.findMatches(rootEl, acc, selector);
          }
        }
        return acc;
      };

      SelectorTree.prototype.getSelectors = function(acc, selectorFirst) {
        var selector, selectorSnippet, tree, _ref;
        if (acc == null) {
          acc = {};
        }
        if (selectorFirst == null) {
          selectorFirst = '';
        }
        _ref = this.children;
        for (selectorSnippet in _ref) {
          tree = _ref[selectorSnippet];
          selector = "" + selectorFirst + " " + selectorSnippet;
          if (tree.data.length > 0) {
            acc[selector] = tree.data;
          } else {
            tree.getSelector(acc, selector);
          }
        }
        return acc;
      };

      SelectorTree.prototype._get = function(chunks) {
        var child, first;
        if (chunks.length) {
          first = chunks.shift();
          child = this.children[first];
          if (child) {
            return child._get(chunks);
          } else {
            return [];
          }
        } else {
          return this.data;
        }
      };

      SelectorTree.prototype.get = function(selector) {
        var chunks;
        chunks = CHUNKIFY(selector);
        return this._get(chunks);
      };

      return SelectorTree;

    })();
  });

}).call(this);

(function() {
  var __slice = [].slice,
    __hasProp = {}.hasOwnProperty,
    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };

  define('polyfill-path/fixed-point-runner', ['underscore', 'less', 'eventemitter2', 'selector-set'], function(_, less, EventEmitter, SelectorSet) {
    var CSS_FUNCTION_WRAPPER, CSS_SELECTIVITY_COMPARATOR, FixedPointRunner, IMPORTANT_COMPARATOR, IMPORTANT_FIXER, SPECIFICITY_SORT;
    CSS_SELECTIVITY_COMPARATOR = function(cls1, cls2) {
      var compare, elements1, elements2, isClassOrAttrib, isElementOrPseudo, isIdAttrib;
      elements1 = cls1.elements;
      elements2 = cls2.elements;
      if (!(elements1 || elements2)) {
        console.error('BUG: Selectivity Comparator has null elements');
      }
      compare = function(iterator, els1, els2) {
        var x1, x2;
        x1 = _.reduce(elements1, iterator, 0);
        x2 = _.reduce(elements2, iterator, 0);
        if (x1 < x2) {
          return -1;
        }
        if (x1 > x2) {
          return 1;
        }
        return 0;
      };
      isIdAttrib = function(n, el) {
        var _ref, _ref1;
        return (_ref = '#' === ((_ref1 = el.value) != null ? _ref1[0] : void 0)) != null ? _ref : n + {
          1: n
        };
      };
      isClassOrAttrib = function(n, el) {
        if ('.' === el.value[0] || '[' === el.value[0]) {
          return n + 1;
        }
        return n;
      };
      isElementOrPseudo = function(n, el) {
        if ((el.value instanceof less.tree.Attribute) || ':' === el.value[0] || /^[a-zA-Z]/.test(el.value)) {
          return n + 1;
        }
        return n;
      };
      return compare(isIdAttrib) || compare(isClassOrAttrib) || compare(isElementOrPseudo);
    };
    SPECIFICITY_SORT = function(autogenClasses) {
      var autogenClass, foundDisplayRule, i, newRules, rule, _i, _j, _len, _len1, _ref;
      newRules = [];
      autogenClasses.sort(CSS_SELECTIVITY_COMPARATOR);
      for (_i = 0, _len = autogenClasses.length; _i < _len; _i++) {
        autogenClass = autogenClasses[_i];
        _ref = autogenClass.rules;
        for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
          rule = _ref[_j];
          newRules.push(rule);
        }
      }
      foundDisplayRule = false;
      newRules.reverse();
      i = 0;
      while (i < newRules.length) {
        if ('display' === newRules[i].name) {
          if (foundDisplayRule) {
            newRules.splice(i, 1);
            continue;
          } else {
            foundDisplayRule = true;
          }
        }
        i += 1;
      }
      return newRules;
    };
    IMPORTANT_FIXER = function(autogenRules) {
      var r, v, _i, _len, _ref, _results;
      _results = [];
      for (_i = 0, _len = autogenRules.length; _i < _len; _i++) {
        r = autogenRules[_i];
        if (!r.important) {
          v = (_ref = r.value.value) != null ? _ref[0] : void 0;
          if (v instanceof less.tree.Anonymous && /\!important$/.test(v.value)) {
            r.important = ' !important';
            _results.push(v.value = v.value.replace(/\s+\!important$/, ''));
          } else {
            _results.push(void 0);
          }
        } else {
          _results.push(void 0);
        }
      }
      return _results;
    };
    IMPORTANT_COMPARATOR = function(a, b) {
      if (a.important && b.important) {
        return 0;
      }
      if (a.important) {
        return -1;
      }
      if (b.important) {
        return 1;
      }
      return 0;
    };
    CSS_FUNCTION_WRAPPER = function(funcName, func) {
      return function() {
        var ret;
        ret = func.apply(this, [this.env].concat(__slice.call(arguments)));
        if (ret == null) {
          return new less.tree.Call(funcName, _.toArray(arguments));
        } else if (ret.toCSS) {
          return ret;
        } else if (ret instanceof Array) {
          return new less.tree.ArrayTreeNode(ret);
        } else if (_.isString(ret)) {
          return new less.tree.Quoted("'" + ret + "'", ret);
        } else if (_.isNumber(ret)) {
          return new less.tree.Dimension(ret);
        } else {
          return new less.tree.Anonymous(ret);
        }
      };
    };
    return FixedPointRunner = (function(_super) {
      __extends(FixedPointRunner, _super);

      function FixedPointRunner(rootNode, plugins, set, removeAutogenClasses) {
        var func, funcName, plugin, ruleFunc, ruleName, _i, _len, _ref, _ref1, _ref2;
        this.rootNode = rootNode;
        this.plugins = plugins;
        this.set = set;
        this.removeAutogenClasses = removeAutogenClasses;
        FixedPointRunner.__super__.constructor.call(this, {
          wildcard: true
        });
        this.squirreledEnv = {};
        this.functions = {};
        this.lookupClasses = {};
        this.lookupCounter = 0;
        this.rules = [];
        _ref = this.plugins;
        for (_i = 0, _len = _ref.length; _i < _len; _i++) {
          plugin = _ref[_i];
          _ref1 = plugin.functions;
          for (funcName in _ref1) {
            func = _ref1[funcName];
            this.functions[funcName] = func.bind(plugin);
          }
          _ref2 = plugin.rules;
          for (ruleName in _ref2) {
            ruleFunc = _ref2[ruleName];
            this.rules.push({
              name: ruleName,
              func: ruleFunc.bind(plugin)
            });
          }
        }
      }

      FixedPointRunner.prototype.lookupAutogenClasses = function(domnode) {
        var classes, cls, foundClasses, _i, _len;
        if (domnode.className) {
          if ('string' === typeof domnode.className) {
            classes = domnode.className;
          } else {
            classes = domnode.className.baseVal;
          }
          classes = classes.split(' ');
          foundClasses = [];
          for (_i = 0, _len = classes.length; _i < _len; _i++) {
            cls = classes[_i];
            if (/^js-polyfill-autoclass-/.test(cls)) {
              foundClasses = foundClasses.concat(this.set.get("." + cls));
            }
          }
          return foundClasses;
        } else {
          return [];
        }
      };

      FixedPointRunner.prototype.tick = function(interestingNodes) {
        var domnode, env, _i, _len,
          _this = this;
        this.emit('tick.start', interestingNodes.length);
        this.somethingChanged = 0;
        env = new less.tree.evalEnv();
        env.state = {};
        env.helpers = {
          interestingByHref: function(href) {
            var id;
            if ('#' !== href[0]) {
              console.error('ERROR: href must start with a # character');
            }
            id = href.substring(1);
            if (!_this.squirreledEnv[id]) {
              console.error('BUG: id was not marked and squirreled before being looked up');
            }
            return _this.squirreledEnv[id];
          },
          markInterestingByHref: function(href) {
            var id, target, wasAlreadyMarked;
            if ('#' !== href[0]) {
              console.error('ERROR: href must start with a # character');
            }
            id = href.substring(1);
            wasAlreadyMarked = !!_this.squirreledEnv[id];
            if (!wasAlreadyMarked) {
              target = document.getElementById(id);
              if (target) {
                _this.somethingChanged += 1;
                target.classList.add('js-polyfill-interesting');
                target.classList.add('js-polyfill-target');
              } else {
                console.warn("ERROR: Invalid target id: #" + id);
              }
            }
            return !wasAlreadyMarked;
          },
          didSomthingNonIdempotent: function(msg) {
            return _this.somethingChanged += 1;
          }
        };
        for (_i = 0, _len = interestingNodes.length; _i < _len; _i++) {
          domnode = interestingNodes[_i];
          this.evalNode(env, domnode);
        }
        this.emit('tick.end', this.somethingChanged);
        return this.somethingChanged;
      };

      FixedPointRunner.prototype.pullRulesFromCache = function(domnode) {
        var autogenClasses, autogenRule, autogenRules, filteredRules, id, name, _i, _len;
        if (domnode.jsPolyfillId) {
          filteredRules = this.lookupClasses[domnode.jsPolyfillId];
          if (filteredRules) {
            return filteredRules;
          }
        }
        id = this.lookupCounter += 1;
        autogenClasses = this.lookupAutogenClasses(domnode);
        autogenRules = SPECIFICITY_SORT(autogenClasses);
        IMPORTANT_FIXER(autogenRules);
        autogenRules.sort(IMPORTANT_COMPARATOR);
        filteredRules = {};
        for (_i = 0, _len = autogenRules.length; _i < _len; _i++) {
          autogenRule = autogenRules[_i];
          name = autogenRule.name;
          if (name instanceof Array) {
            name = name.join('');
          }
          if (filteredRules[name] == null) {
            filteredRules[name] = [];
          }
          filteredRules[name].push(autogenRule);
        }
        this.lookupClasses[id] = filteredRules;
        domnode.jsPolyfillId = id;
        return filteredRules;
      };

      FixedPointRunner.prototype.evalNode = function(env, domnode) {
        var autogenRule, autogenRules, beforeSomethingChanged, filteredRules, i, pluginRule, rule, ruleName, ruleValNode, rules, somethingNotCompleted, targetEnv, understood, understoodRules, unused, _i, _j, _k, _len, _len1, _len2, _ref;
        this.emit('tick.node', domnode);
        somethingNotCompleted = false;
        if (domnode.compareDocumentPosition(document.body) & Node.DOCUMENT_POSITION_DISCONNECTED) {
          return;
        }
        env.helpers.contextNode = domnode;
        autogenRules = this.pullRulesFromCache(domnode);
        _ref = this.rules;
        for (_i = 0, _len = _ref.length; _i < _len; _i++) {
          pluginRule = _ref[_i];
          if ('*' === pluginRule.name) {
            filteredRules = [];
            for (unused in autogenRules) {
              rules = autogenRules[unused];
              for (_j = 0, _len1 = rules.length; _j < _len1; _j++) {
                rule = rules[_j];
                filteredRules.push(rule);
              }
            }
          } else {
            filteredRules = autogenRules[pluginRule.name];
          }
          understoodRules = {};
          if (filteredRules) {
            for (i = _k = 0, _len2 = filteredRules.length; _k < _len2; i = ++_k) {
              autogenRule = filteredRules[i];
              ruleName = autogenRule.name;
              if (ruleName instanceof Array) {
                ruleName = ruleName.join('');
              }
              ruleValNode = autogenRule.value;
              if (!ruleName) {
                continue;
              }
              if (ruleName in understoodRules) {
                continue;
              }
              if ('completed' === domnode.getAttribute("data-js-polyfill-rule-" + ruleName)) {
                continue;
              }
              beforeSomethingChanged = this.somethingChanged;
              if ('*' === pluginRule.name) {
                understood = pluginRule.func(env, ruleName, ruleValNode);
              } else {
                understood = pluginRule.func(env, ruleValNode);
              }
              somethingNotCompleted = true;
              if (understood) {
                understoodRules[ruleName] = true;
                domnode.setAttribute("data-js-polyfill-rule-" + ruleName, 'evaluated');
                if (understood === 'RULE_COMPLETED') {
                  this.somethingChanged += 1;
                  domnode.setAttribute("data-js-polyfill-rule-" + ruleName, 'completed');
                } else if (understood === 'NODE_REMOVED') {
                  if (domnode.jsPolyfillId) {
                    delete this.lookupClasses[domnode.jsPolyfillId];
                  }
                  return;
                }
                break;
              }
              if (beforeSomethingChanged !== this.somethingChanged) {
                break;
              }
            }
          }
        }
        if (domnode.classList.contains('js-polyfill-target')) {
          targetEnv = {
            helpers: _.clone(env.helpers),
            state: JSON.parse(JSON.stringify(_.omit(env.state, 'buckets')))
          };
          targetEnv.helpers.contextNode = domnode;
          return this.squirreledEnv[domnode.id] = targetEnv;
        } else if (!somethingNotCompleted) {
          domnode.classList.remove('js-polyfill-interesting');
          if (domnode.jsPolyfillId) {
            return delete this.lookupClasses[domnode.jsPolyfillId];
          }
        }
      };

      FixedPointRunner.prototype.setUp = function() {
        var func, funcName, _ref, _results;
        this.emit('runner.start');
        _ref = this.functions;
        _results = [];
        for (funcName in _ref) {
          func = _ref[funcName];
          _results.push(less.tree.functions[funcName] = CSS_FUNCTION_WRAPPER(funcName, func));
        }
        return _results;
      };

      FixedPointRunner.prototype.done = function() {
        var className, classes, discardedClasses, el, funcName, node, nonPolyfillClasses, _i, _j, _k, _l, _len, _len1, _len2, _len3, _ref, _ref1;
        for (funcName in this.functions) {
          delete less.tree.functions[funcName];
        }
        discardedClasses = ['js-polyfill-evaluated', 'js-polyfill-interesting', 'js-polyfill-target'];
        for (_i = 0, _len = discardedClasses.length; _i < _len; _i++) {
          className = discardedClasses[_i];
          _ref = this.rootNode.querySelectorAll("." + className);
          for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
            el = _ref[_j];
            el.classList.remove(className);
          }
        }
        _ref1 = this.rootNode.querySelectorAll('.js-polyfill-autoclass:not(.js-polyfill-autoclass-keep), .js-polyfill-pseudo');
        for (_k = 0, _len2 = _ref1.length; _k < _len2; _k++) {
          node = _ref1[_k];
          if (node.classList) {
            if ('string' === typeof node.className) {
              classes = node.className;
            } else {
              classes = node.className.baseVal;
            }
            classes = classes.split(' ');
            nonPolyfillClasses = [];
            for (_l = 0, _len3 = classes.length; _l < _len3; _l++) {
              className = classes[_l];
              if (!/^js-polyfill-/.test(className)) {
                nonPolyfillClasses.push(className);
              }
              if (!this.removeAutogenClasses) {
                if (/^js-polyfill-autoclass-/.test(className)) {
                  nonPolyfillClasses.push(className);
                }
              }
            }
            if (nonPolyfillClasses.length > 0) {
              node.className = nonPolyfillClasses.join(' ');
            } else {
              node.removeAttribute('class');
            }
          }
        }
        return this.emit('runner.end');
      };

      FixedPointRunner.prototype.run = function() {
        var changes, interestingNodes;
        this.setUp();
        interestingNodes = this.rootNode.querySelectorAll('.js-polyfill-interesting');
        while (changes = this.tick(interestingNodes)) {
          interestingNodes = this.rootNode.querySelectorAll('.js-polyfill-interesting');
        }
        return this.done();
      };

      return FixedPointRunner;

    })(EventEmitter);
  });

}).call(this);

(function() {
  var __hasProp = {}.hasOwnProperty,
    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
    __indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };

  define('polyfill-path/selector-visitor', ['underscore', 'less', 'sizzle', 'eventemitter2'], function(_, less, Sizzle, EventEmitter) {
    var AbstractSelectorVisitor, LessVisitor, PSEUDO_CLASSES, _ref;
    LessVisitor = (function(_super) {
      __extends(LessVisitor, _super);

      function LessVisitor(rootNode) {
        this.rootNode = rootNode;
        this._visitor = new less.tree.visitor(this);
        this._frames = [];
      }

      LessVisitor.prototype.run = function(root) {
        return this._visitor.visit(root);
      };

      LessVisitor.prototype.peek = function() {
        return this._frames[this._frames.length - 1];
      };

      LessVisitor.prototype.push = function(val) {
        return this._frames.push(val);
      };

      LessVisitor.prototype.pop = function() {
        return this._frames.pop();
      };

      return LessVisitor;

    })(EventEmitter);
    PSEUDO_CLASSES = ['before', 'after', 'outside', 'footnote-call', 'footnote-marker', 'deferred'];
    return AbstractSelectorVisitor = (function(_super) {
      __extends(AbstractSelectorVisitor, _super);

      function AbstractSelectorVisitor() {
        _ref = AbstractSelectorVisitor.__super__.constructor.apply(this, arguments);
        return _ref;
      }

      AbstractSelectorVisitor.prototype.isPreEvalVisitor = false;

      AbstractSelectorVisitor.prototype.isPreVisitor = false;

      AbstractSelectorVisitor.prototype.isReplacing = false;

      AbstractSelectorVisitor.prototype.operateOnElements = function(frame, nodes, ruleSet, domSelector, pseudoSelector, originalSelector) {};

      AbstractSelectorVisitor.prototype.doSelector = function(node, visitArgs) {
        var element, i, isPseudo, sliceIndex, _i, _len, _ref1;
        isPseudo = function(name) {
          var _ref1;
          return _.isString(name) && /^:/.test(name) && (_ref1 = name.replace(/:/g, ''), __indexOf.call(PSEUDO_CLASSES, _ref1) >= 0);
        };
        sliceIndex = node.elements.length;
        _ref1 = node.elements;
        for (i = _i = 0, _len = _ref1.length; _i < _len; i = ++_i) {
          element = _ref1[i];
          if (isPseudo(element.value)) {
            sliceIndex = i;
            break;
          }
        }
        return {
          originalSelector: node,
          domSelector: node.createDerived(node.elements.slice(0, sliceIndex)),
          pseudoSelector: node.createDerived(node.elements.slice(sliceIndex))
        };
      };

      AbstractSelectorVisitor.prototype.getNodes = function(selectorStr) {
        var err;
        try {
          return this.rootNode.querySelectorAll(selectorStr);
        } catch (_error) {
          err = _error;
          return Sizzle(selectorStr, this.rootNode);
        }
      };

      AbstractSelectorVisitor.prototype.visitRuleset = function(node) {
        var context, el, path, sel, selector, selectorStr, _i, _j, _k, _len, _len1, _len2, _ref1, _ref2, _results,
          _this = this;
        if (node.root) {
          return;
        }
        _ref1 = node.paths;
        _results = [];
        for (_i = 0, _len = _ref1.length; _i < _len; _i++) {
          path = _ref1[_i];
          context = [];
          for (_j = 0, _len1 = path.length; _j < _len1; _j++) {
            sel = path[_j];
            selector = this.doSelector(sel);
            selectorStr = [];
            _ref2 = selector.domSelector.elements;
            for (_k = 0, _len2 = _ref2.length; _k < _len2; _k++) {
              el = _ref2[_k];
              selectorStr.push(el.toCSS({}));
              if (/^[\*]/.test(el.value)) {
                selectorStr.push(':not(.js-polyfill-pseudo)');
              }
            }
            selectorStr = selectorStr.join('');
            context.push(selectorStr);
          }
          selectorStr = context.join('');
          this.emit('selector.start', selectorStr, node.debugInfo);
          this.emit('selector.end', selectorStr, node.debugInfo, function() {
            return _this.getNodes(selectorStr);
          });
          if (__indexOf.call(selectorStr, '@') >= 0 || __indexOf.call(selectorStr, '|') >= 0) {

          } else {
            this.operateOnElements(null, node, selector.domSelector, selector.pseudoSelector, selector.originalSelector, selectorStr);
          }
          _results.push(context.pop());
        }
        return _results;
      };

      return AbstractSelectorVisitor;

    })(LessVisitor);
  });

}).call(this);

(function() {
  define('polyfill-path/extras', ['underscore', 'sizzle', 'less'], function(_, Sizzle, less) {
    var ElementExtras, pseudo, uniqueId, uniqueIdCount, _base, _base1, _base2, _i, _len, _ref;
    uniqueIdCount = 0;
    uniqueId = function() {
      return "id-added-via-x-ensure-id-" + (uniqueIdCount++);
    };
    _ref = ['deferred', 'pass', 'match'];
    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
      pseudo = _ref[_i];
      if ((_base = Sizzle.selectors.match)[pseudo] == null) {
        _base[pseudo] = RegExp(":?" + pseudo);
      }
      if ((_base1 = Sizzle.selectors.find)[pseudo] == null) {
        _base1[pseudo] = function(match, context, isXML) {
          return context;
        };
      }
      if ((_base2 = Sizzle.selectors.pseudos)[pseudo] == null) {
        _base2[pseudo] = function(elem) {
          return elem;
        };
      }
    }
    ElementExtras = (function() {
      function ElementExtras() {}

      ElementExtras.prototype.functions = {
        'x-selector': function(env, selectorNode) {
          if (!(selectorNode instanceof less.tree.Quoted)) {
            console.warn("ERROR: x-selector(): expects a Quoted");
          }
          return selectorNode.value;
        },
        'x-sort': function(env, bucketElementsNode, sortBySelector) {
          var domAry, sorted,
            _this = this;
          if (sortBySelector == null) {
            sortBySelector = null;
          }
          domAry = bucketElementsNode["eval"](env).values;
          sorted = _.clone(domAry).sort(function(a, b) {
            if (sortBySelector) {
              a = a.querySelector(sortBySelector.value);
              if (!a) {
                console.error('ERROR: Attempting to sort but cannot find selector');
              }
              a = a != null ? a.textContent.trim() : void 0;
              b = b.querySelector(sortBySelector.value);
              if (!b) {
                console.error('ERROR: Attempting to sort but cannot find selector');
              }
              b = b != null ? b.textContent.trim() : void 0;
            } else {
              a = a.textContent.trim();
              b = b.textContent.trim();
            }
            if (a < b) {
              return -1;
            }
            if (a > b) {
              return 1;
            }
            return 0;
          });
          return sorted;
        },
        'x-target-is': function(env, targetIdNode, selectorNode) {
          var context, href, targetEnv;
          if (selectorNode == null) {
            selectorNode = null;
          }
          href = targetIdNode["eval"](env).value;
          selectorNode = selectorNode["eval"](env);
          if (!(selectorNode instanceof less.tree.Quoted)) {
            console.warn("ERROR: x-target-is() expects a Quoted");
          }
          if (!env.helpers.markInterestingByHref(href)) {
            targetEnv = env.helpers.interestingByHref(href);
            context = targetEnv.helpers.contextNode;
            if (Sizzle.matchesSelector(context, selectorNode.value)) {
              return '';
            } else {
              return null;
            }
          }
          return null;
        }
      };

      ElementExtras.prototype.rules = {
        'x-tag-name': function(env, tagNameNode) {
          var child, context, newEl, oldTagName, tagName, _j, _len1, _ref1;
          tagNameNode = tagNameNode["eval"](env);
          if (!(tagNameNode instanceof less.tree.Quoted)) {
            console.warn("ERROR: move-to: expects a Quoted");
          }
          context = env.helpers.contextNode;
          oldTagName = context.tagName.toLowerCase();
          tagName = tagNameNode.value.toLowerCase();
          if (oldTagName !== tagName) {
            newEl = document.createElement(tagName);
            newEl.className = context.className;
            newEl.setAttribute('data-js-polyfill-tagname-orig', oldTagName);
            _ref1 = context.childNodes;
            for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
              child = _ref1[_j];
              newEl.appendChild(child);
            }
            context.parentNode.replaceChild(newEl, context);
            env.helpers.contextNode = newEl;
            env.helpers.didSomthingNonIdempotent('x-tag-name');
            return 'RULE_COMPLETED';
          }
          return false;
        },
        'x-ensure-id': function(env, attributeNameNode) {
          attributeNameNode = attributeNameNode["eval"](env);
          if (!(attributeNameNode instanceof less.tree.Quoted)) {
            console.warn("ERROR: x-ensure-id: expects a Quoted");
          }
          if (!env.helpers.contextNode.getAttribute(attributeNameNode.value)) {
            env.helpers.contextNode.setAttribute(attributeNameNode.value, uniqueId());
            env.helpers.didSomthingNonIdempotent('x-ensure-id');
            return 'RULE_COMPLETED';
          }
          return false;
        },
        'x-attr': function(env, attrsAndVals) {
          var setAttr, v, _j, _len1, _ref1, _results,
            _this = this;
          attrsAndVals = attrsAndVals["eval"](env);
          setAttr = function(val) {
            var arg, args, attrName, str, _j, _len1;
            attrName = _.first(val.value).value;
            args = _.rest(val.value);
            str = [];
            for (_j = 0, _len1 = args.length; _j < _len1; _j++) {
              arg = args[_j];
              if (arg instanceof less.tree.Quoted) {
                str.push(arg.value);
              } else if (arg instanceof less.tree.Call) {
                if ('content' === arg.name) {
                  arg.name = 'x-string-set-content';
                  val = arg["eval"](env);
                  if (val instanceof less.tree.Call) {
                    return null;
                  }
                  str.push(val.value);
                  arg.name = 'content';
                } else {
                  return null;
                }
              } else {
                str.push(arg.value);
              }
            }
            return env.helpers.contextNode.setAttribute(attrName, str.join(''));
          };
          if (attrsAndVals instanceof less.tree.Expression) {
            return setAttr(attrsAndVals);
          } else if (attrsAndVals instanceof less.tree.Value) {
            _ref1 = attrsAndVals.value;
            _results = [];
            for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
              v = _ref1[_j];
              _results.push(setAttr(v));
            }
            return _results;
          } else {
            return console.warn('ERROR: invalid arguments given to "x-attr:"');
          }
        }
      };

      return ElementExtras;

    })();
    return {
      ElementExtras: ElementExtras
    };
  });

}).call(this);

(function() {
  define('polyfill-path/plugins', ['underscore', 'sizzle', 'less'], function(_, Sizzle, less) {
    var ArrayTreeNode, ContentSet, DisplayNone, MoveTo, StringSet, TargetCounter, TargetText, contentsFuncBuilder;
    less.tree.ArrayTreeNode = ArrayTreeNode = (function() {
      function ArrayTreeNode(values) {
        this.values = values;
      }

      ArrayTreeNode.prototype["eval"] = function() {
        return this;
      };

      return ArrayTreeNode;

    })();
    MoveTo = (function() {
      function MoveTo() {}

      MoveTo.prototype.functions = {
        'pending': function(env, bucketNameNode) {
          var domAry, footnote, node, pendingPseudo, _i, _j, _len, _len1, _ref;
          bucketNameNode = bucketNameNode["eval"](env);
          if (!(bucketNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: pending(): expects a Keyword");
          }
          domAry = ((_ref = env.state.buckets) != null ? _ref[bucketNameNode.value] : void 0) || [];
          for (_i = 0, _len = domAry.length; _i < _len; _i++) {
            node = domAry[_i];
            pendingPseudo = node.querySelector('.js-polyfill-pseudo[data-js-polyfill-rule-content="pending"]');
            if (pendingPseudo) {
              return null;
            }
          }
          for (_j = 0, _len1 = domAry.length; _j < _len1; _j++) {
            node = domAry[_j];
            footnote = node.querySelector('.js-polyfill-pseudo-footnote-call');
            if (footnote) {
              if (node.nextSibling) {
                node.parentNode.insertBefore(footnote, node.nextSibling);
              } else {
                node.parentNode.append(footnote);
              }
            }
          }
          if (env.state.buckets) {
            delete env.state.buckets[bucketNameNode.value];
          }
          return domAry || [];
        }
      };

      MoveTo.prototype.rules = {
        'move-to': function(env, bucketNameNode) {
          var bucketName, domnode, ruleName, _base, _base1;
          bucketNameNode = bucketNameNode["eval"](env);
          if (!(bucketNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: move-to: expects a Keyword");
          }
          ruleName = 'move-to';
          domnode = env.helpers.contextNode;
          if ('pending' === domnode.getAttribute('data-js-polyfill-rule-content') || domnode.querySelector("[data-js-polyfill-rule-content='pending']")) {
            return false;
          }
          bucketName = bucketNameNode.value;
          if ((_base = env.state).buckets == null) {
            _base.buckets = {};
          }
          if ((_base1 = env.state.buckets)[bucketName] == null) {
            _base1[bucketName] = [];
          }
          env.state.buckets[bucketName].push(env.helpers.contextNode);
          return 'RULE_COMPLETED';
        }
      };

      return MoveTo;

    })();
    DisplayNone = (function() {
      function DisplayNone() {}

      DisplayNone.prototype.rules = {
        'display': function(env, valNode) {
          var context;
          valNode = valNode["eval"](env);
          if (!(valNode instanceof less.tree.Anonymous)) {
            return;
          }
          if ('none' === valNode.value) {
            context = env.helpers.contextNode;
            context.parentNode.removeChild(context);
            env.helpers.didSomthingNonIdempotent('display:none');
            return 'NODE_REMOVED';
          }
          return true;
        }
      };

      return DisplayNone;

    })();
    TargetCounter = (function() {
      function TargetCounter() {}

      TargetCounter.prototype.functions = {
        'x-parent': function(env, valNode) {
          var context;
          context = env.helpers.contextNode;
          env.helpers.contextNode = context.parentNode;
          valNode = valNode["eval"](env);
          env.helpers.contextNode = context;
          return valNode;
        },
        'attr': function(env, attrNameNode) {
          var context, val;
          attrNameNode = attrNameNode["eval"](env);
          if (!(attrNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: attr(): expects a Keyword");
          }
          context = env.helpers.contextNode;
          val = context.getAttribute(attrNameNode.value);
          if (val && !isNaN(val)) {
            val = parseInt(val);
          }
          if (!val) {
            if (context.classList.contains('js-polyfill-pseudo')) {
              if (context.classList.contains('js-polyfill-pseudo-outside')) {
                context = context.querySelector(':not(.js-polyfill-pseudo)');
              } else {
                if (context.parentNode) {
                  context = context.parentNode;
                  while (context.classList.contains('js-polyfill-pseudo')) {
                    context = context.parentNode;
                    if (!context) {
                      break;
                    }
                  }
                }
              }
              val = context.getAttribute(attrNameNode.value);
              if (val && !isNaN(val)) {
                val = parseInt(val);
              }
            }
          }
          return val;
        },
        'counter': function(env, counterNameNode, counterType) {
          var _ref;
          if (counterType == null) {
            counterType = null;
          }
          counterNameNode = counterNameNode["eval"](env);
          if (!(counterNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: counter(): expects a Keyword");
          }
          return this.numberingStyle((_ref = env.state.counters) != null ? _ref[counterNameNode.value] : void 0, counterType != null ? counterType["eval"](env).value : void 0);
        },
        'target-counter': function(env, targetIdNode, counterNameNode, counterType) {
          var counterName, href, targetEnv, _ref;
          if (counterType == null) {
            counterType = null;
          }
          if (!counterNameNode) {
            console.error("ERROR: target-counter(): expects a 2nd argument");
            return;
          }
          counterNameNode = counterNameNode["eval"](env);
          if (!(counterNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: target-counter(): expects a Keyword");
          }
          href = targetIdNode["eval"](env).value;
          counterName = counterNameNode.value;
          if (!href || href[0] !== '#' || href.length < 2) {
            return null;
          }
          if (!env.helpers.markInterestingByHref(href)) {
            targetEnv = env.helpers.interestingByHref(href);
            return this.numberingStyle((_ref = targetEnv.state.counters) != null ? _ref[counterName] : void 0, counterType != null ? counterType["eval"](env).value : void 0);
          }
          return null;
        }
      };

      TargetCounter.prototype.rules = {
        'counter-increment': function(env, valNode) {
          var counterName, counterValue, counters, countersAndNumbers, _base, _base1;
          countersAndNumbers = valNode["eval"](env);
          counters = this.parseCounters(countersAndNumbers, 1);
          if ((_base = env.state).counters == null) {
            _base.counters = {};
          }
          for (counterName in counters) {
            counterValue = counters[counterName];
            if ((_base1 = env.state.counters)[counterName] == null) {
              _base1[counterName] = 0;
            }
            env.state.counters[counterName] += counterValue;
          }
          return true;
        },
        'counter-reset': function(env, valNode) {
          var counterName, counterValue, counters, countersAndNumbers, _base;
          countersAndNumbers = valNode["eval"](env);
          counters = this.parseCounters(countersAndNumbers, 0);
          if ((_base = env.state).counters == null) {
            _base.counters = {};
          }
          for (counterName in counters) {
            counterValue = counters[counterName];
            env.state.counters[counterName] = counterValue;
          }
          return true;
        }
      };

      TargetCounter.prototype.parseCounters = function(val, defaultNum) {
        var counters, cssStr, i, name, tokens;
        cssStr = val.toCSS({});
        tokens = cssStr.split(' ');
        counters = {};
        if ('none' === tokens[0]) {
          return counters;
        }
        i = 0;
        while (i < tokens.length) {
          name = tokens[i];
          if (i === tokens.length - 1) {
            val = defaultNum;
          } else if (isNaN(parseInt(tokens[i + 1]))) {
            val = defaultNum;
          } else {
            val = parseInt(tokens[i + 1]);
            i++;
          }
          counters[name] = val;
          i++;
        }
        return counters;
      };

      TargetCounter.prototype.numberingStyle = function(num, style) {
        if (num == null) {
          num = 0;
        }
        if (style == null) {
          style = 'decimal';
        }
        switch (style) {
          case 'decimal-leading-zero':
            if (num < 10) {
              return "0" + num;
            } else {
              return num;
            }
            break;
          case 'lower-roman':
            return this.toRoman(num).toLowerCase();
          case 'upper-roman':
            return this.toRoman(num);
          case 'lower-latin':
            if (!((1 <= num && num <= 26))) {
              console.warn('ERROR: number out of range (must be 1...26)');
              return num;
            } else {
              return String.fromCharCode(num + 96);
            }
            break;
          case 'upper-latin':
            if (!((1 <= num && num <= 26))) {
              console.warn('ERROR: number out of range (must be 1...26)');
              return num;
            } else {
              return String.fromCharCode(num + 64);
            }
            break;
          case 'decimal':
            return num;
          default:
            console.warn("ERROR: Counter numbering not supported for list type " + style + ". Using decimal.");
            return num;
        }
      };

      TargetCounter.prototype.toRoman = function(num) {
        var integer, numeral, result, romanNumeralMap, _i, _len, _ref;
        romanNumeralMap = [['M', 1000], ['CM', 900], ['D', 500], ['CD', 400], ['C', 100], ['XC', 90], ['L', 50], ['XL', 40], ['X', 10], ['IX', 9], ['V', 5], ['IV', 4], ['I', 1]];
        if (!((0 < num && num < 5000))) {
          console.warn('ERROR: number out of range (must be 1..4999)');
          return "" + num;
        }
        result = '';
        for (_i = 0, _len = romanNumeralMap.length; _i < _len; _i++) {
          _ref = romanNumeralMap[_i], numeral = _ref[0], integer = _ref[1];
          while (num >= integer) {
            result += numeral;
            num -= integer;
          }
        }
        return result;
      };

      return TargetCounter;

    })();
    contentsFuncBuilder = function(defaultType) {
      return function(env, typeNode) {
        var child, el, els, evaluated, getContents, selector, text, type, val, _i, _j, _k, _l, _len, _len1, _len2, _len3, _ref, _ref1, _ref2, _ref3, _ref4, _ref5, _ref6,
          _this = this;
        typeNode = typeNode != null ? typeNode["eval"](env) : void 0;
        if ((!typeNode) || typeNode instanceof less.tree.Keyword) {
          getContents = function() {
            var child, el, _i, _len, _ref, _ref1;
            el = env.helpers.contextNode.cloneNode(true);
            _ref = _.toArray(el.children);
            for (_i = 0, _len = _ref.length; _i < _len; _i++) {
              child = _ref[_i];
              if ((_ref1 = child.classList) != null ? _ref1.contains('js-polyfill-pseudo') : void 0) {
                el.removeChild(child);
              }
            }
            return el.textContent;
          };
          type = (typeNode != null ? typeNode.value : void 0) || defaultType;
          switch (type) {
            case 'contents':
              val = getContents();
              break;
            case 'first-letter':
              val = (_ref = getContents()) != null ? _ref.trim()[0] : void 0;
              break;
            case 'before':
              text = [];
              _ref1 = env.helpers.contextNode.children;
              for (_i = 0, _len = _ref1.length; _i < _len; _i++) {
                child = _ref1[_i];
                if ((_ref2 = child.classList) != null ? _ref2.contains('js-polyfill-pseudo-before') : void 0) {
                  text.push(child.textContent);
                }
              }
              evaluated = false;
              _ref3 = env.helpers.contextNode.children;
              for (_j = 0, _len1 = _ref3.length; _j < _len1; _j++) {
                child = _ref3[_j];
                if (child.classList.contains('js-polyfill-evaluated')) {
                  evaluated = true;
                }
              }
              if (evaluated) {
                val = text.join('');
              }
              break;
            case 'after':
              text = [];
              _ref4 = env.helpers.contextNode.children;
              for (_k = 0, _len2 = _ref4.length; _k < _len2; _k++) {
                child = _ref4[_k];
                if ((_ref5 = child.classList) != null ? _ref5.contains('js-polyfill-pseudo-after') : void 0) {
                  text.push(child.textContent);
                }
              }
              evaluated = false;
              _ref6 = env.helpers.contextNode.children;
              for (_l = 0, _len3 = _ref6.length; _l < _len3; _l++) {
                child = _ref6[_l];
                if (child.classList.contains('js-polyfill-evaluated')) {
                  evaluated = true;
                }
              }
              if (evaluated) {
                val = text.join('');
              }
              break;
            default:
              val = typeNode.toCSS({});
              console.error("ERROR: invalid argument to content(). argument=[" + val + "]");
              val = '';
          }
          return val;
        } else if (typeNode instanceof less.tree.Quoted) {
          selector = typeNode.value;
          els = Sizzle(selector, env.helpers.contextNode);
          if (!els[0]) {
            return;
          }
          text = (function() {
            var _len4, _m, _results;
            _results = [];
            for (_m = 0, _len4 = els.length; _m < _len4; _m++) {
              el = els[_m];
              _results.push(el.textContent);
            }
            return _results;
          })();
          return text.join('');
        } else {
          return console.warn("ERROR: content(): expects a Keyword or a Selector String");
        }
      };
    };
    TargetText = (function() {
      function TargetText() {}

      TargetText.prototype.functions = {
        'x-target-text-content': contentsFuncBuilder('before'),
        'target-text': function(env, targetIdNode, contentTypeNode) {
          var contents, href, targetEnv;
          if (contentTypeNode == null) {
            contentTypeNode = null;
          }
          href = targetIdNode["eval"](env).value;
          if (!env.helpers.markInterestingByHref(href)) {
            targetEnv = env.helpers.interestingByHref(href);
            if (!(contentTypeNode instanceof less.tree.Call)) {
              console.warn("ERROR: target-text() expects a function Call");
            }
            if ('content' !== contentTypeNode.name) {
              console.warn("ERROR: target-text() expects a Call to content()");
            }
            contentTypeNode.name = 'x-target-text-content';
            contents = contentTypeNode["eval"](targetEnv).value;
            contentTypeNode.name = 'content';
            return contents;
          }
          return null;
        }
      };

      return TargetText;

    })();
    StringSet = (function() {
      function StringSet() {}

      StringSet.prototype.functions = {
        'x-string-set-content': contentsFuncBuilder('contents'),
        'string': function(env, stringNameNode) {
          var str, _ref;
          stringNameNode = stringNameNode["eval"](env);
          if (!(stringNameNode instanceof less.tree.Keyword)) {
            console.warn("ERROR: string(): expects a Keyword");
          }
          str = (_ref = env.state.strings) != null ? _ref[stringNameNode.value] : void 0;
          return str;
        }
      };

      StringSet.prototype.rules = {
        'string-set': function(env, stringsAndVals) {
          var setString, v, _i, _len, _ref,
            _this = this;
          stringsAndVals = stringsAndVals["eval"](env);
          setString = function(val) {
            var arg, args, str, stringName, _base, _i, _len;
            stringName = _.first(val.value).value;
            args = _.rest(val.value);
            str = [];
            for (_i = 0, _len = args.length; _i < _len; _i++) {
              arg = args[_i];
              if (arg instanceof less.tree.Quoted) {
                str.push(arg.value);
              } else if (arg instanceof less.tree.Call) {
                if ('content' === arg.name) {
                  arg.name = 'x-string-set-content';
                  val = arg["eval"](env);
                  if (val instanceof less.tree.Call) {
                    return null;
                  }
                  str.push(val.value);
                  arg.name = 'content';
                } else {
                  console.warn("ERROR: invalid function used. only content() is acceptable. name=[" + arg.name + "]");
                }
              } else {
                str.push(arg.value);
              }
            }
            if ((_base = env.state).strings == null) {
              _base.strings = {};
            }
            return env.state.strings[stringName] = str.join('');
          };
          if (stringsAndVals instanceof less.tree.Expression) {
            setString(stringsAndVals);
          } else if (stringsAndVals instanceof less.tree.Value) {
            _ref = stringsAndVals.value;
            for (_i = 0, _len = _ref.length; _i < _len; _i++) {
              v = _ref[_i];
              setString(v);
            }
          } else {
            console.warn('ERROR: invalid arguments given to string-set');
            return false;
          }
          return true;
        }
      };

      return StringSet;

    })();
    ContentSet = (function() {
      function ContentSet() {}

      ContentSet.prototype.rules = {
        'content': function(env, valNode) {
          var child, domnode, pseudoAfter, val, values, _i, _j, _len, _len1, _ref, _ref1;
          valNode = valNode["eval"](env);
          values = this.evaluateValNode(valNode);
          if (values) {
            domnode = env.helpers.contextNode;
            _ref = _.toArray(domnode.childNodes);
            for (_i = 0, _len = _ref.length; _i < _len; _i++) {
              child = _ref[_i];
              if (!((_ref1 = child.classList) != null ? _ref1.contains('js-polyfill-pseudo') : void 0)) {
                domnode.removeChild(child);
              }
            }
            pseudoAfter = domnode.querySelector('.js-polyfill-pseudo-after');
            for (_j = 0, _len1 = values.length; _j < _len1; _j++) {
              val = values[_j];
              switch (typeof val) {
                case 'string':
                  val = document.createTextNode(val);
                  break;
                case 'number':
                  val = document.createTextNode(val);
                  break;
                default:
                  if (val.ELEMENT_NODE) {

                  } else {
                    throw new Error('BUG: content rule only supports string, number, and DOM Node objects');
                  }
              }
              if (pseudoAfter) {
                domnode.insertBefore(val, pseudoAfter);
              } else {
                domnode.appendChild(val);
              }
            }
            domnode.classList.add('js-polyfill-evaluated');
            return 'RULE_COMPLETED';
          }
          return false;
        }
      };

      ContentSet.prototype.evaluateValNode = function(valNode) {
        var el, r, ret, val, vals, _i, _j, _len, _len1, _ref;
        ret = [];
        if (valNode instanceof less.tree.Expression) {
          vals = valNode.value;
        } else {
          vals = [valNode];
        }
        for (_i = 0, _len = vals.length; _i < _len; _i++) {
          val = vals[_i];
          if (val instanceof less.tree.Expression) {
            r = this.evaluateValNode(val);
            if (r === null) {
              return null;
            }
            ret = ret.concat(r);
          } else if (val instanceof less.tree.Quoted) {
            ret.push(val.value);
          } else if (val instanceof less.tree.Dimension) {
            ret.push(val.value);
          } else if (val instanceof less.tree.ArrayTreeNode) {
            _ref = val.values;
            for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
              el = _ref[_j];
              ret.push(el);
            }
          } else if (val instanceof less.tree.Call) {
            return null;
          } else if (val instanceof less.tree.URL) {
            return null;
          } else if (val instanceof less.tree.Comment) {
            ret.push('');
          } else {
            console.warn("BUG: Attempting to set content: to something unknown. [" + val.value + "]");
            console.warn(JSON.stringify(val));
            return null;
          }
        }
        return ret;
      };

      return ContentSet;

    })();
    return {
      MoveTo: MoveTo,
      DisplayNone: DisplayNone,
      TargetCounter: TargetCounter,
      TargetText: TargetText,
      StringSet: StringSet,
      ContentSet: ContentSet
    };
  });

}).call(this);

(function() {
  var __hasProp = {}.hasOwnProperty,
    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };

  define('polyfill-path/less-converters', ['underscore', 'sizzle', 'cs!polyfill-path/selector-visitor'], function(_, Sizzle, AbstractSelectorVisitor) {
    var AutogenClass, PSEUDO_CLASSES, PseudoExpander, freshClass, freshClassIdCounter, slugify;
    PSEUDO_CLASSES = ['before', 'after', 'outside', 'footnote-call', 'footnote-marker', 'running', 'deferred'];
    slugify = function(str) {
      str = str.replace(/\ +/g, ' ');
      str = str.replace(/[^A-Za-z0-9>\[\]\(\)\.]/g, '-');
      str = str.replace(/[\[\]\(\)]/g, '_');
      str = str.replace(/-+/g, '-');
      str = str.replace(/>/g, '-child-');
      str = str.replace(/\./g, '-dot-');
      str = str.replace(/-+/g, '-');
      str = str.replace(/^-|-$/g, '');
      return str;
    };
    freshClassIdCounter = 0;
    freshClass = function(selectorStr) {
      selectorStr = slugify(selectorStr);
      return "js-polyfill-autoclass-" + (freshClassIdCounter++) + "-" + selectorStr;
    };
    AutogenClass = (function() {
      function AutogenClass(selectorStr, elements, rules) {
        this.selectorStr = selectorStr;
        this.elements = elements;
        this.rules = rules;
      }

      return AutogenClass;

    })();
    PseudoExpander = (function(_super) {
      var selectorTestNode;

      __extends(PseudoExpander, _super);

      PseudoExpander.prototype.PSEUDO_ELEMENT_NAME = 'span';

      selectorTestNode = document.createElement('span');

      function PseudoExpander(root, set, interestingSet, plugins) {
        var plugin, ruleName, _i, _len;
        this.set = set;
        this.interestingSet = interestingSet;
        PseudoExpander.__super__.constructor.apply(this, arguments);
        this.interestingRules = [];
        for (_i = 0, _len = plugins.length; _i < _len; _i++) {
          plugin = plugins[_i];
          for (ruleName in plugin.rules || {}) {
            this.interestingRules[ruleName] = true;
          }
        }
      }

      PseudoExpander.prototype.hasInterestingRules = function(ruleSet) {
        var rule, _i, _len, _ref;
        if (this.interestingRules['*']) {
          return true;
        }
        _ref = ruleSet.rules;
        for (_i = 0, _len = _ref.length; _i < _len; _i++) {
          rule = _ref[_i];
          if (rule.name in this.interestingRules) {
            return true;
          }
        }
      };

      PseudoExpander.prototype.operateOnElements = function(frame, ruleSet, domSelector, pseudoSelector, originalSelector, selectorStr) {
        var autoClass, className, cls, context, e, hasInterestingRules, isBrowserSelector, newClassName, newContexts, node, op, originalContext, outside, pseudoName, pseudoNode, simpleExpand, _i, _j, _len, _len1, _ref;
        if (!pseudoSelector.elements.length) {
          try {
            selectorTestNode.querySelector(selectorStr);
            isBrowserSelector = true;
          } catch (_error) {
            e = _error;
            isBrowserSelector = false;
          }
          if (isBrowserSelector) {
            autoClass = new AutogenClass(selectorStr, originalSelector.elements, ruleSet.rules);
            this.set.add(selectorStr, autoClass);
          }
          hasInterestingRules = this.hasInterestingRules(ruleSet);
          if (!isBrowserSelector || hasInterestingRules) {
            className = freshClass(selectorStr);
            _ref = this.getNodes(selectorStr);
            for (_i = 0, _len = _ref.length; _i < _len; _i++) {
              node = _ref[_i];
              if (node.className == null) {
                node.className = '';
              }
              if (node.classList) {
                if (!isBrowserSelector) {
                  node.classList.add('js-polyfill-autoclass-keep');
                }
                node.classList.add('js-polyfill-autoclass');
                node.classList.add('js-polyfill-interesting');
                node.classList.add(className);
              }
            }
            selectorStr = "." + className;
            autoClass = new AutogenClass(selectorStr, originalSelector.elements, ruleSet.rules);
            this.interestingSet.add(selectorStr, autoClass);
            if (!isBrowserSelector && !hasInterestingRules) {
              return this.set.add(selectorStr, autoClass);
            }
          }
        } else {
          newContexts = (function() {
            var _j, _k, _len1, _len2, _ref1, _ref2, _results,
              _this = this;
            _ref1 = this.getNodes(selectorStr);
            _results = [];
            for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
              originalContext = _ref1[_j];
              context = originalContext;
              _ref2 = pseudoSelector.elements;
              for (_k = 0, _len2 = _ref2.length; _k < _len2; _k++) {
                pseudoNode = _ref2[_k];
                pseudoName = pseudoNode.value.replace('::', ':');
                simpleExpand = function(op, pseudoName) {
                  var cls, pseudo;
                  cls = "js-polyfill-pseudo-" + pseudoName;
                  pseudo = Sizzle(" > ." + cls + ", > .js-polyfill-pseudo-outside > ." + cls, context)[0];
                  if (pseudo) {
                    return context = pseudo;
                  } else {
                    pseudo = document.createElement(_this.PSEUDO_ELEMENT_NAME);
                    pseudo.classList.add('js-polyfill-pseudo');
                    pseudo.classList.add(cls);
                    switch (op) {
                      case 'append':
                        context.appendChild(pseudo);
                        break;
                      case 'prepend':
                        context.insertBefore(pseudo, context.firstChild);
                    }
                    return context = pseudo;
                  }
                };
                selectorStr += pseudoName;
                switch (pseudoName) {
                  case ':before':
                    simpleExpand('prepend', 'before');
                    break;
                  case ':after':
                    simpleExpand('append', 'after');
                    break;
                  case ':footnote-marker':
                    simpleExpand('prepend', 'footnote-marker');
                    break;
                  case ':footnote-call':
                    simpleExpand('append', 'footnote-call');
                    break;
                  case ':running':
                    simpleExpand('append', 'footnote-call');
                    break;
                  case ':outside':
                    op = 'wrap';
                    pseudoName = 'outside';
                    cls = "js-polyfill-pseudo-" + pseudoName;
                    if (context.parentNode.classList.contains(cls)) {
                      context = context.parentNode;
                    } else {
                      outside = document.createElement(this.PSEUDO_ELEMENT_NAME);
                      outside.classList.add('js-polyfill-pseudo');
                      outside.classList.add(cls);
                      context.parentNode.replaceChild(outside, context);
                      outside.appendChild(context);
                      context = outside;
                    }
                    break;
                  case ':deferred':
                    break;
                  default:
                    console.error("ERROR: Attempted to expand unsupported pseudo element " + pseudoName);
                }
              }
              _results.push(context);
            }
            return _results;
          }).call(this);
          newClassName = freshClass(selectorStr);
          for (_j = 0, _len1 = newContexts.length; _j < _len1; _j++) {
            context = newContexts[_j];
            context.classList.add('js-polyfill-autoclass');
            context.classList.add('js-polyfill-interesting');
            context.classList.add(newClassName);
          }
          autoClass = new AutogenClass(selectorStr, pseudoSelector.elements, ruleSet.rules, this.hasInterestingRules(ruleSet));
          selectorStr = "." + newClassName;
          this.set.add(selectorStr, autoClass);
          if (this.hasInterestingRules(ruleSet)) {
            return this.interestingSet.add(selectorStr, autoClass);
          }
        }
      };

      return PseudoExpander;

    })(AbstractSelectorVisitor);
    return {
      PseudoExpander: PseudoExpander
    };
  });

}).call(this);

(function() {
  var __hasProp = {}.hasOwnProperty,
    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
    __slice = [].slice;

  define('polyfill-path/index', ['underscore', 'less', 'eventemitter2', 'selector-set', 'cs!polyfill-path/selector-tree', 'cs!polyfill-path/less-converters', 'cs!polyfill-path/plugins', 'cs!polyfill-path/extras', 'cs!polyfill-path/fixed-point-runner', 'cs!polyfill-path/selector-visitor'], function(_, less, EventEmitter, SelectorSet, SelectorTree, LESS_CONVERTERS, PLUGINS, EXTRAS, FixedPointRunner, AbstractSelectorVisitor) {
    var CSSPolyfills, ContentSet, DisplayNone, ElementExtras, MoveTo, PseudoExpander, StringSet, TargetCounter, TargetText;
    PseudoExpander = LESS_CONVERTERS.PseudoExpander;
    MoveTo = PLUGINS.MoveTo;
    DisplayNone = PLUGINS.DisplayNone;
    TargetCounter = PLUGINS.TargetCounter;
    TargetText = PLUGINS.TargetText;
    StringSet = PLUGINS.StringSet;
    ContentSet = PLUGINS.ContentSet;
    ElementExtras = EXTRAS.ElementExtras;
    CSSPolyfills = (function(_super) {
      __extends(CSSPolyfills, _super);

      CSSPolyfills.DEFAULT_PLUGINS = [new MoveTo(), new DisplayNone(), new TargetCounter(), new TargetText(), new StringSet(), new ElementExtras(), new ContentSet()];

      function CSSPolyfills(config) {
        if (config == null) {
          config = {};
        }
        _.extend(this, config);
        _.defaults(this, {
          plugins: [],
          lessPlugins: [],
          pseudoExpanderClass: PseudoExpander,
          doNotIncludeDefaultPlugins: false,
          removeAutogenClasses: true
        });
        if (!this.doNotIncludeDefaultPlugins) {
          this.plugins = this.plugins.concat(CSSPolyfills.DEFAULT_PLUGINS);
        }
      }

      CSSPolyfills.prototype.runTree = function(rootNode, lessTree, cb) {
        var SelectorSet_add, allSet, bindAll, changeLessTree, interestingSet, outputRulesetsToString, pseudoExpander, runFixedPoint,
          _this = this;
        if (cb == null) {
          cb = null;
        }
        this.emit('start');
        if (rootNode.jquery) {
          rootNode = rootNode[0];
        }
        bindAll = function(emitter, eventNames) {
          return _.each(eventNames, function(name) {
            return emitter.on(name, function() {
              return _this.emit.apply(_this, [name].concat(__slice.call(arguments)));
            });
          });
        };
        SelectorSet_add = SelectorSet.prototype.add;
        SelectorSet.prototype.add = function(sel, data) {
          SelectorSet_add.apply(this, arguments);
          if (this.addedSelectors == null) {
            this.addedSelectors = [];
          }
          return this.addedSelectors.push({
            selector: sel,
            data: data
          });
        };
        outputRulesetsToString = function(outputRulesets) {
          var allSelectors, autogenClass, comment, cssStrs, env, originalSelectorStr, rule, rules, selector, selectorStr, start, _i, _j, _len, _len1, _ref;
          cssStrs = [];
          env = new less.tree.evalEnv();
          env.compress = false;
          env.dumpLineNumbers = 'all';
          start = new Date();
          allSelectors = outputRulesets.addedSelectors || [];
          for (_i = 0, _len = allSelectors.length; _i < _len; _i++) {
            _ref = allSelectors[_i], selectorStr = _ref.selector, autogenClass = _ref.data;
            rules = autogenClass.rules, selector = autogenClass.selector;
            originalSelectorStr = selector;
            if (originalSelectorStr === selectorStr) {
              comment = '';
            } else {
              comment = "/* BASED_ON: " + originalSelectorStr + " */";
            }
            cssStrs.push("" + selectorStr + " { " + comment);
            for (_j = 0, _len1 = rules.length; _j < _len1; _j++) {
              rule = rules[_j];
              cssStrs.push("  " + (rule.toCSS(env)));
            }
            cssStrs.push("}");
          }
          return cssStrs.join('\n');
        };
        allSet = new SelectorSet();
        interestingSet = new SelectorTree();
        changeLessTree = function(plugins) {
          var env;
          env = new less.tree.evalEnv();
          env.compress = false;
          env.dumpLineNumbers = 'all';
          env.plugins = plugins;
          return lessTree.toCSS(env);
        };
        runFixedPoint = function(plugins) {
          var fixedPointRunner;
          fixedPointRunner = new FixedPointRunner(rootNode, plugins, interestingSet, _this.removeAutogenClasses);
          bindAll(fixedPointRunner, ['runner.start', 'runner.end', 'tick.start', 'tick.node', 'tick.end']);
          fixedPointRunner.run();
          return fixedPointRunner;
        };
        if (this.pseudoExpanderClass) {
          pseudoExpander = new this.pseudoExpanderClass(rootNode, allSet, interestingSet, this.plugins);
          bindAll(pseudoExpander, ['selector.start', 'selector.end']);
          this.lessPlugins.push(pseudoExpander);
        }
        changeLessTree(this.lessPlugins);
        runFixedPoint(this.plugins);
        if (typeof cb === "function") {
          cb(null, outputRulesetsToString(allSet));
        }
        return this.emit('end');
      };

      CSSPolyfills.prototype.run = function(rootNode, cssStyle, filename, cb) {
        var _this = this;
        return this.parse(cssStyle, filename, function(err, lessTree) {
          if (err) {
            return typeof cb === "function" ? cb(err, lessTree) : void 0;
          }
          return _this.runTree(rootNode, lessTree, cb);
        });
      };

      CSSPolyfills.prototype.parse = function(cssStyle, filename, cb) {
        var env, parser;
        env = {
          compress: false,
          dumpLineNumbers: 'all',
          filename: filename
        };
        parser = new less.Parser(env);
        return parser.parse(cssStyle, cb);
      };

      return CSSPolyfills;

    })(EventEmitter);
    CSSPolyfills.less = less;
    CSSPolyfills.AbstractSelectorVisitor = AbstractSelectorVisitor;
    if (typeof window !== "undefined" && window !== null) {
      window.CSSPolyfills = CSSPolyfills;
    }
    return CSSPolyfills;
  });

}).call(this);

(function() {
  this.define = this.__polyfills_originalGlobals['define'];

  if (typeof this.define === "function") {
    this.define('polyfill-path/index', function() {
      return this.CSSPolyfills;
    });
  }

  this.__polyfills_originalGlobals = void 0;

}).call(this);