From ffdeabe22ba767c4b4de601a551c1fe18a71b568 Mon Sep 17 00:00:00 2001
From: Koeun Choi <koeun.choi@samsung.com>
Date: Thu, 21 Feb 2013 17:14:32 +0900
Subject: [PATCH] build-tools : upgrade less to v1.3.3

Change-Id: I277543bad8301affac58c678811373b1e04190a5
---
 build-tools/README.txt                             |   1 +
 build-tools/lib/less/browser.js                    | 296 ++++++--
 build-tools/lib/less/colors.js                     | 152 ++++
 build-tools/lib/less/functions.js                  | 216 +++++-
 build-tools/lib/less/index.js                      | 227 ++++--
 build-tools/lib/less/lessc_helper.js               |  62 ++
 build-tools/lib/less/parser.js                     | 801 ++++++++++++++++-----
 build-tools/lib/less/rhino.js                      | 109 ++-
 build-tools/lib/less/tree.js                       |  36 +-
 build-tools/lib/less/tree/alpha.js                 |   2 +-
 build-tools/lib/less/tree/anonymous.js             |  18 +-
 build-tools/lib/less/tree/assignment.js            |  19 +
 build-tools/lib/less/tree/call.js                  |  29 +-
 build-tools/lib/less/tree/color.js                 |  12 +-
 build-tools/lib/less/tree/comment.js               |   2 +-
 build-tools/lib/less/tree/condition.js             |  42 ++
 build-tools/lib/less/tree/dimension.js             |  19 +-
 build-tools/lib/less/tree/directive.js             |  16 +-
 build-tools/lib/less/tree/element.js               |  34 +-
 build-tools/lib/less/tree/expression.js            |   4 +-
 build-tools/lib/less/tree/import.js                |  51 +-
 build-tools/lib/less/tree/javascript.js            |   2 +-
 build-tools/lib/less/tree/keyword.js               |  14 +-
 build-tools/lib/less/tree/media.js                 | 121 ++++
 build-tools/lib/less/tree/mixin.js                 | 188 +++--
 build-tools/lib/less/tree/operation.js             |   7 +-
 build-tools/lib/less/tree/paren.js                 |  16 +
 build-tools/lib/less/tree/quoted.js                |  18 +-
 build-tools/lib/less/tree/ratio.js                 |  13 +
 build-tools/lib/less/tree/rule.js                  |  19 +-
 build-tools/lib/less/tree/ruleset.js               | 278 ++++++-
 build-tools/lib/less/tree/selector.js              |  50 +-
 build-tools/lib/less/tree/unicode-descriptor.js    |  13 +
 build-tools/lib/less/tree/url.js                   |  32 +-
 build-tools/lib/less/tree/value.js                 |   2 +-
 build-tools/lib/less/tree/variable.js              |  22 +-
 .../common/jquery.mobile.forms.textinput.less      |   2 +-
 37 files changed, 2372 insertions(+), 573 deletions(-)
 create mode 100644 build-tools/lib/less/colors.js
 create mode 100644 build-tools/lib/less/lessc_helper.js
 create mode 100644 build-tools/lib/less/tree/assignment.js
 create mode 100644 build-tools/lib/less/tree/condition.js
 create mode 100644 build-tools/lib/less/tree/media.js
 create mode 100644 build-tools/lib/less/tree/paren.js
 create mode 100644 build-tools/lib/less/tree/ratio.js
 create mode 100644 build-tools/lib/less/tree/unicode-descriptor.js

diff --git a/build-tools/README.txt b/build-tools/README.txt
index 0efd403..cf716fd 100644
--- a/build-tools/README.txt
+++ b/build-tools/README.txt
@@ -1,6 +1,7 @@
 Tizen Web UI Framework includes following tools used on build;
 
 * less (http://lesscss.org)
+	* Version: 1.3.3
 	* Description: A dynamic CSS language compiler based on node.js
 	* Mods
 		* Support rem unit (build-tools/lib/less/parser.js)
diff --git a/build-tools/lib/less/browser.js b/build-tools/lib/less/browser.js
index cba4c3b..e00ff27 100644
--- a/build-tools/lib/less/browser.js
+++ b/build-tools/lib/less/browser.js
@@ -2,10 +2,7 @@
 // browser.js - client-side engine
 //
 
-var isFileProtocol = (location.protocol === 'file:'    ||
-                      location.protocol === 'chrome:'  ||
-                      location.protocol === 'chrome-extension:'  ||
-                      location.protocol === 'resource:');
+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'   ||
@@ -20,42 +17,64 @@ less.env = less.env || (location.hostname == '127.0.0.1' ||
 // doesn't start loading before the stylesheets are parsed.
 // Setting this to `true` can result in flickering.
 //
-less.async = false;
+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];
+}
+
 //
 // Watch mode
 //
-less.watch   = function () { return this.watchMode = true };
-less.unwatch = function () { return this.watchMode = false };
+less.watch   = function () {	
+	if (!less.watchMode ){		
+		less.env = 'development';
+		initRunningMode();
+	}
+	return this.watchMode = true 
+};
 
-if (less.env === 'development') {
-    less.optimization = 0;
+less.unwatch = function () {clearInterval(less.watchTimer); return this.watchMode = false; };
+
+function initRunningMode(){
+	if (less.env === 'development') {		
+		less.optimization = 0;		
+		less.watchTimer = setInterval(function () {			
+			if (less.watchMode) {
+				loadStyleSheets(function (e, root, _, sheet, env) {
+					if (root) {
+						createCSS(root.toCSS(), sheet, env.lastModified);
+					}
+				});
+			}
+		}, less.poll);
+	} else {
+		less.optimization = 3;
+	}
+}
 
-    if (/!watch/.test(location.hash)) {
-        less.watch();
-    }
-    less.watchTimer = setInterval(function () {
-        if (less.watchMode) {
-            loadStyleSheets(function (root, sheet, env) {
-                if (root) {
-                    createCSS(root.toCSS(), sheet, env.lastModified);
-                }
-            });
-        }
-    }, less.poll);
-} else {
-    less.optimization = 3;
+if (/!watch/.test(location.hash)) {
+	less.watch();
 }
 
-var cache;
+var cache = null;
 
-try {
-    cache = (typeof(window.localStorage) === 'undefined') ? null : window.localStorage;
-} catch (_) {
-    cache = null;
+if (less.env != 'development') {
+    try {
+        cache = (typeof(window.localStorage) === 'undefined') ? null : window.localStorage;
+    } catch (_) {}
 }
 
 //
@@ -73,12 +92,27 @@ for (var i = 0; i < links.length; i++) {
     }
 }
 
+//
+// With this function, it's possible to alter variables and re-render
+// CSS without reloading less-files
+//
+var session_cache = '';
+less.modifyVars = function(record) {
+	var str = session_cache;
+    for (name in record) {
+        str += ((name.slice(0,1) === '@')? '' : '@') + name +': '+ 
+                ((record[name].slice(-1) === ';')? record[name] : record[name] +';');
+    }
+    new(less.Parser)().parse(str, function (e, root) {
+        createCSS(root.toCSS(), less.sheets[less.sheets.length - 1]);
+    });
+};
 
 less.refresh = function (reload) {
     var startTime, endTime;
     startTime = endTime = new(Date);
 
-    loadStyleSheets(function (root, sheet, env) {
+    loadStyleSheets(function (e, root, _, sheet, env) {
         if (env.local) {
             log("loading " + sheet.href + " from cache.");
         } else {
@@ -100,15 +134,18 @@ function loadStyles() {
     var styles = document.getElementsByTagName('style');
     for (var i = 0; i < styles.length; i++) {
         if (styles[i].type.match(typePattern)) {
-            new(less.Parser)().parse(styles[i].innerHTML || '', function (e, tree) {
+            new(less.Parser)({
+                filename: document.location.href.replace(/#.*$/, ''),
+                dumpLineNumbers: less.dumpLineNumbers
+            }).parse(styles[i].innerHTML || '', function (e, tree) {
                 var css = tree.toCSS();
                 var style = styles[i];
-                try {
+                style.type = 'text/css';
+                if (style.styleSheet) {
+                    style.styleSheet.cssText = css;
+                } else {
                     style.innerHTML = css;
-                } catch (_) {
-                    style.styleSheets.cssText = css;
                 }
-                style.type = 'text/css';
             });
         }
     }
@@ -120,40 +157,139 @@ function loadStyleSheets(callback, reload) {
     }
 }
 
+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 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-]+:)?\/\/(?:[^\/\?#]+\/)|([\/\\]))?((?:[^\/\\\?#]+[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/,
+        urlParts = url.match(urlPartsRegex),
+        returner = {}, directories = [], i, baseUrlParts;
+
+    if (!urlParts) {
+        throw new Error("Could not parse sheet href - '"+url+"'");
+    }
+
+    // Stylesheets in IE don't always return the full path    
+    if (!urlParts[1] || urlParts[2]) {
+        baseUrlParts = baseUrl.match(urlPartsRegex);
+        if (!baseUrlParts) {
+            throw new Error("Could not parse page url - '"+baseUrl+"'");
+        }
+        urlParts[1] = baseUrlParts[1];
+        if (!urlParts[2]) {
+            urlParts[3] = baseUrlParts[3] + urlParts[3];
+        }
+    }
+    
+    if (urlParts[3]) {
+        directories = urlParts[3].replace("\\", "/").split("/");
+
+        for(i = 0; i < directories.length; i++) {
+            if (directories[i] === ".." && i > 0) {
+                directories.splice(i-1, 2);
+                i -= 2;
+            }
+        }
+    }
+
+    returner.hostPart = urlParts[1];
+    returner.directories = directories;
+    returner.path = urlParts[1] + directories.join("/");
+    returner.fileUrl = returner.path + (urlParts[4] || "");
+    returner.url = returner.fileUrl + (urlParts[5] || "");
+    return returner;
+}
+
 function loadStyleSheet(sheet, callback, reload, remaining) {
-    var url       = window.location.href.replace(/[#?].*$/, '');
-    var href      = sheet.href.replace(/\?.*$/, '');
+    // sheet may be set to the stylesheet for the initial load or a collection of properties including
+    // some env variables for imports
+    var contents  = sheet.contents || {};
+    var files     = sheet.files || {};
+    var hrefParts = extractUrlParts(sheet.href, window.location.href);
+    var href      = hrefParts.url;
     var css       = cache && cache.getItem(href);
     var timestamp = cache && cache.getItem(href + ':timestamp');
     var styles    = { css: css, timestamp: timestamp };
+    var rootpath;
 
-    // Stylesheets in IE don't always return the full path
-    if (! /^(https?|file):/.test(href)) {
-        if (href.charAt(0) == "/") {
-            href = window.location.protocol + "//" + window.location.host + href;
+    if (less.relativeUrls) {
+        if (less.rootpath) {
+            if (sheet.entryPath) {
+                rootpath = extractUrlParts(less.rootpath + pathDiff(hrefParts.path, sheet.entryPath)).path;
+            } else {
+                rootpath = less.rootpath;
+            }
+        } else {
+            rootpath = hrefParts.path;
+        }
+    } else  {
+        if (less.rootpath) {
+            rootpath = less.rootpath;
         } else {
-            href = url.slice(0, url.lastIndexOf('/') + 1) + href;
+            if (sheet.entryPath) {
+                rootpath = sheet.entryPath;
+            } else {
+                rootpath = hrefParts.path;
+            }
         }
     }
 
-    xhr(sheet.href, sheet.type, function (data, lastModified) {
+    xhr(href, sheet.type, function (data, lastModified) {
+        // Store data this session
+        session_cache += data.replace(/@import .+?;/ig, '');
+
         if (!reload && styles && lastModified &&
            (new(Date)(lastModified).valueOf() ===
             new(Date)(styles.timestamp).valueOf())) {
             // Use local copy
             createCSS(styles.css, sheet);
-            callback(null, sheet, { local: true, remaining: remaining });
+            callback(null, null, data, sheet, { local: true, remaining: remaining }, href);
         } else {
             // Use remote copy (re-parse)
             try {
+                contents[href] = data;  // Updating top importing parser content cache
                 new(less.Parser)({
                     optimization: less.optimization,
-                    paths: [href.replace(/[\w\.-]+$/, '')],
-                    mime: sheet.type
+                    paths: [hrefParts.path],
+                    entryPath: sheet.entryPath || hrefParts.path,
+                    mime: sheet.type,
+                    filename: href,
+                    rootpath: rootpath,
+                    relativeUrls: sheet.relativeUrls,
+                    contents: contents,    // Passing top importing parser content cache ref down.
+                    files: files,
+                    dumpLineNumbers: less.dumpLineNumbers
                 }).parse(data, function (e, root) {
                     if (e) { return error(e, href) }
                     try {
-                        callback(root, sheet, { local: false, lastModified: lastModified, remaining: remaining });
+                        callback(e, root, data, sheet, { local: false, lastModified: lastModified, remaining: remaining }, href);
                         removeNode(document.getElementById('less-error-message:' + extractId(href)));
                     } catch (e) {
                         error(e, href);
@@ -171,8 +307,7 @@ function loadStyleSheet(sheet, callback, reload, remaining) {
 function extractId(href) {
     return href.replace(/^[a-z]+:\/\/?[^\/]+/, '' )  // Remove protocol & domain
                .replace(/^\//,                 '' )  // Remove root /
-               .replace(/\?.*$/,               '' )  // Remove query
-               .replace(/\.[^\.\/]+$/,         '' )  // Remove file extension
+               .replace(/\.[a-zA-Z]+$/,        '' )  // Remove simple extension
                .replace(/[^\.\w-]+/g,          '-')  // Replace illegal characters
                .replace(/\./g,                 ':'); // Replace dots with colons(for valid id)
 }
@@ -181,7 +316,7 @@ function createCSS(styles, sheet, lastModified) {
     var css;
 
     // Strip the query-string
-    var href = sheet.href ? sheet.href.replace(/\?.*$/, '') : '';
+    var href = sheet.href || '';
 
     // If there is no title set, use the filename, minus the extension
     var id = 'less:' + (sheet.title || extractId(href));
@@ -190,9 +325,10 @@ function createCSS(styles, sheet, lastModified) {
     if ((css = document.getElementById(id)) === null) {
         css = document.createElement('style');
         css.type = 'text/css';
-        css.media = sheet.media || 'screen';
+        if( sheet.media ){ css.media = sheet.media; }
         css.id = id;
-        document.getElementsByTagName('head')[0].appendChild(css);
+        var nextEl = sheet && sheet.nextSibling || null;
+        (nextEl || document.getElementsByTagName('head')[0]).parentNode.insertBefore(css, nextEl);
     }
 
     if (css.styleSheet) { // IE
@@ -216,14 +352,19 @@ function createCSS(styles, sheet, lastModified) {
     // Don't update the local store if the file wasn't modified
     if (lastModified && cache) {
         log('saving ' + href + ' to cache.');
-        cache.setItem(href, styles);
-        cache.setItem(href + ':timestamp', lastModified);
+        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');
+        }
     }
 }
 
 function xhr(url, type, callback, errback) {
     var xhr = getXMLHttpRequest();
-    var async = isFileProtocol ? false : less.async;
+    var async = isFileProtocol ? less.fileAsync : less.async;
 
     if (typeof(xhr.overrideMimeType) === 'function') {
         xhr.overrideMimeType('text/css');
@@ -232,8 +373,8 @@ function xhr(url, type, callback, errback) {
     xhr.setRequestHeader('Accept', type || 'text/x-less, text/css; q=0.9, */*; q=0.5');
     xhr.send(null);
 
-    if (isFileProtocol) {
-        if (xhr.status === 0) {
+    if (isFileProtocol && !less.fileAsync) {
+        if (xhr.status === 0 || (xhr.status >= 200 && xhr.status < 300)) {
             callback(xhr.responseText);
         } else {
             errback(xhr.status, url);
@@ -281,29 +422,33 @@ function log(str) {
 
 function error(e, href) {
     var id = 'less-error-message:' + extractId(href);
-
-    var template = ['<ul>',
-                        '<li><label>[-1]</label><pre class="ctx">{0}</pre></li>',
-                        '<li><label>[0]</label><pre>{current}</pre></li>',
-                        '<li><label>[1]</label><pre class="ctx">{2}</pre></li>',
-                    '</ul>'].join('\n');
-
-    var elem = document.createElement('div'), timer, content;
+    var template = '<li><label>{line}</label><pre class="{class}">{content}</pre></li>';
+    var elem = document.createElement('div'), timer, content, error = [];
+    var filename = e.filename || href;
+    var filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];
 
     elem.id        = id;
     elem.className = "less-error-message";
 
     content = '<h3>'  + (e.message || 'There is an error in your .less file') +
-              '</h3>' + '<p><a href="' + href   + '">' + href + "</a> ";
+              '</h3>' + '<p>in <a href="' + filename   + '">' + filenameNoPath + "</a> ";
 
-    if (e.extract) {
+    var errorline = function (e, i, classname) {
+        if (e.extract[i]) {
+            error.push(template.replace(/\{line\}/, parseInt(e.line) + (i - 1))
+                               .replace(/\{class\}/, classname)
+                               .replace(/\{content\}/, e.extract[i]));
+        }
+    };
+
+    if (e.stack) {
+        content += '<br/>' + e.stack.split('\n').slice(1).join('<br/>');
+    } else if (e.extract) {
+        errorline(e, 0, '');
+        errorline(e, 1, 'line');
+        errorline(e, 2, '');
         content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':</p>' +
-            template.replace(/\[(-?\d)\]/g, function (_, i) {
-                return (parseInt(e.line) + parseInt(i)) || '';
-            }).replace(/\{(\d)\}/g, function (_, i) {
-                return e.extract[parseInt(i)] || '';
-            }).replace(/\{current\}/, e.extract[1].slice(0, e.column) + '<span class="error">' +
-                                      e.extract[1].slice(e.column)    + '</span>');
+                    '<ul>' + error.join('') + '</ul>';
     }
     elem.innerHTML = content;
 
@@ -322,13 +467,13 @@ function error(e, href) {
             'color: #cc7777;',
         '}',
         '.less-error-message pre {',
-            'color: #ee4444;',
+            'color: #dd6666;',
             'padding: 4px 0;',
             'margin: 0;',
             'display: inline-block;',
         '}',
-        '.less-error-message pre.ctx {',
-            'color: #dd4444;',
+        '.less-error-message pre.line {',
+            'color: #ff0000;',
         '}',
         '.less-error-message h3 {',
             'font-size: 20px;',
@@ -372,4 +517,3 @@ function error(e, href) {
         }, 10);
     }
 }
-
diff --git a/build-tools/lib/less/colors.js b/build-tools/lib/less/colors.js
new file mode 100644
index 0000000..b417af6
--- /dev/null
+++ b/build-tools/lib/less/colors.js
@@ -0,0 +1,152 @@
+(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',
+        // 'transparent':'rgba(0,0,0,0)',
+        'turquoise':'#40e0d0',
+        'violet':'#ee82ee',
+        'wheat':'#f5deb3',
+        'white':'#ffffff',
+        'whitesmoke':'#f5f5f5',
+        'yellow':'#ffff00',
+        'yellowgreen':'#9acd32'
+    };
+})(require('./tree'));
diff --git a/build-tools/lib/less/functions.js b/build-tools/lib/less/functions.js
index fc9d86f..b077123 100644
--- a/build-tools/lib/less/functions.js
+++ b/build-tools/lib/less/functions.js
@@ -5,8 +5,8 @@ tree.functions = {
         return this.rgba(r, g, b, 1.0);
     },
     rgba: function (r, g, b, a) {
-        var rgb = [r, g, b].map(function (c) { return number(c) }),
-            a = number(a);
+        var rgb = [r, g, b].map(function (c) { return scaled(c, 256); });
+        a = number(a);
         return new(tree.Color)(rgb, a);
     },
     hsl: function (h, s, l) {
@@ -32,6 +32,36 @@ tree.functions = {
             else                return m1;
         }
     },
+
+    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));
     },
@@ -41,9 +71,24 @@ tree.functions = {
     lightness: function (color) {
         return new(tree.Dimension)(Math.round(color.toHSL().l * 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((0.2126 * (color.rgb[0]/255) +
+            0.7152 * (color.rgb[1]/255) +
+            0.0722 * (color.rgb[2]/255)) *
+            color.alpha * 100), '%');
+    },
     saturate: function (color, amount) {
         var hsl = color.toHSL();
 
@@ -106,6 +151,9 @@ tree.functions = {
     // 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;
@@ -124,6 +172,29 @@ tree.functions = {
     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);
+        }
+        if (typeof threshold === 'undefined') {
+            threshold = 0.43;
+        } else {
+            threshold = threshold.value;
+        }
+        if (((0.2126 * (color.rgb[0]/255) + 0.7152 * (color.rgb[1]/255) + 0.0722 * (color.rgb[2]/255)) * color.alpha) < threshold) {
+            return light;
+        } else {
+            return dark;
+        }
+    },
     e: function (str) {
         return new(tree.Anonymous)(str instanceof tree.JavaScript ? str.evaluated : str);
     },
@@ -143,26 +214,147 @@ tree.functions = {
         str = str.replace(/%%/g, '%');
         return new(tree.Quoted)('"' + str + '"', str);
     },
-    round: function (n) {
+    unit: function (val, unit) {
+        return new(tree.Dimension)(val.value, unit ? unit.toCSS() : "");
+    },
+    round: function (n, f) {
+        var fraction = typeof(f) === "undefined" ? 0 : f.value;
+        return this._math(function(num) { return num.toFixed(fraction); }, n);
+    },
+    ceil: function (n) {
+        return this._math(Math.ceil, n);
+    },
+    floor: function (n) {
+        return this._math(Math.floor, n);
+    },
+    _math: function (fn, n) {
         if (n instanceof tree.Dimension) {
-            return new(tree.Dimension)(Math.round(number(n)), n.unit);
+            return new(tree.Dimension)(fn(parseFloat(n.value)), n.unit);
         } else if (typeof(n) === 'number') {
-            return Math.round(n);
+            return fn(n);
         } else {
-	    throw {
-                error: "RuntimeError",
-                message: "math functions take numbers as parameters"
-            };
+            throw { type: "Argument", message: "argument must be a number" };
         }
     },
     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) {
+            return new(tree.Color)(n.value.slice(1));
+        } 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 (n instanceof tree.Dimension) && n.unit === 'px' ? tree.True : tree.False;
+    },
+    ispercentage: function (n) {
+        return (n instanceof tree.Dimension) && n.unit === '%' ? tree.True : tree.False;
+    },
+    isem: function (n) {
+        return (n instanceof tree.Dimension) && n.unit === 'em' ? tree.True : tree.False;
+    },
+    _isa: function (n, Type) {
+        return (n instanceof Type) ? tree.True : tree.False;
+    },
+    
+    /* Blending modes */
+    
+    multiply: function(color1, color2) {
+        var r = color1.rgb[0] * color2.rgb[0] / 255;
+        var g = color1.rgb[1] * color2.rgb[1] / 255;
+        var b = color1.rgb[2] * color2.rgb[2] / 255;
+        return this.rgb(r, g, b);
+    },
+    screen: function(color1, color2) {
+        var r = 255 - (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255;
+        var g = 255 - (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255;
+        var b = 255 - (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    overlay: function(color1, color2) {
+        var r = color1.rgb[0] < 128 ? 2 * color1.rgb[0] * color2.rgb[0] / 255 : 255 - 2 * (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255;
+        var g = color1.rgb[1] < 128 ? 2 * color1.rgb[1] * color2.rgb[1] / 255 : 255 - 2 * (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255;
+        var b = color1.rgb[2] < 128 ? 2 * color1.rgb[2] * color2.rgb[2] / 255 : 255 - 2 * (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    softlight: function(color1, color2) {
+        var t = color2.rgb[0] * color1.rgb[0] / 255;
+        var r = t + color1.rgb[0] * (255 - (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255 - t) / 255;
+        t = color2.rgb[1] * color1.rgb[1] / 255;
+        var g = t + color1.rgb[1] * (255 - (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255 - t) / 255;
+        t = color2.rgb[2] * color1.rgb[2] / 255;
+        var b = t + color1.rgb[2] * (255 - (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255 - t) / 255;
+        return this.rgb(r, g, b);
+    },
+    hardlight: function(color1, color2) {
+        var r = color2.rgb[0] < 128 ? 2 * color2.rgb[0] * color1.rgb[0] / 255 : 255 - 2 * (255 - color2.rgb[0]) * (255 - color1.rgb[0]) / 255;
+        var g = color2.rgb[1] < 128 ? 2 * color2.rgb[1] * color1.rgb[1] / 255 : 255 - 2 * (255 - color2.rgb[1]) * (255 - color1.rgb[1]) / 255;
+        var b = color2.rgb[2] < 128 ? 2 * color2.rgb[2] * color1.rgb[2] / 255 : 255 - 2 * (255 - color2.rgb[2]) * (255 - color1.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    difference: function(color1, color2) {
+        var r = Math.abs(color1.rgb[0] - color2.rgb[0]);
+        var g = Math.abs(color1.rgb[1] - color2.rgb[1]);
+        var b = Math.abs(color1.rgb[2] - color2.rgb[2]);
+        return this.rgb(r, g, b);
+    },
+    exclusion: function(color1, color2) {
+        var r = color1.rgb[0] + color2.rgb[0] * (255 - color1.rgb[0] - color1.rgb[0]) / 255;
+        var g = color1.rgb[1] + color2.rgb[1] * (255 - color1.rgb[1] - color1.rgb[1]) / 255;
+        var b = color1.rgb[2] + color2.rgb[2] * (255 - color1.rgb[2] - color1.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    average: function(color1, color2) {
+        var r = (color1.rgb[0] + color2.rgb[0]) / 2;
+        var g = (color1.rgb[1] + color2.rgb[1]) / 2;
+        var b = (color1.rgb[2] + color2.rgb[2]) / 2;
+        return this.rgb(r, g, b);
+    },
+    negation: function(color1, color2) {
+        var r = 255 - Math.abs(255 - color2.rgb[0] - color1.rgb[0]);
+        var g = 255 - Math.abs(255 - color2.rgb[1] - color1.rgb[1]);
+        var b = 255 - Math.abs(255 - color2.rgb[2] - color1.rgb[2]);
+        return this.rgb(r, g, b);
+    },
+    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);
     }
 };
 
-function hsla(hsla) {
-    return tree.functions.hsla(hsla.h, hsla.s, hsla.l, hsla.a);
+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 == '%') {
+        return parseFloat(n.value * size / 100);
+    } else {
+        return number(n);
+    }
 }
 
 function number(n) {
@@ -182,4 +374,4 @@ function clamp(val) {
     return Math.min(1, Math.max(0, val));
 }
 
-})(require('less/tree'));
+})(require('./tree'));
diff --git a/build-tools/lib/less/index.js b/build-tools/lib/less/index.js
index c2c248d..37fc902 100644
--- a/build-tools/lib/less/index.js
+++ b/build-tools/lib/less/index.js
@@ -1,18 +1,14 @@
 var path = require('path'),
     sys = require('util'),
+    url = require('url'),
+    http = require('http'),
     fs = require('fs');
 
-try {
-	// For old node.js versions
-	require.paths.unshift( path.join( __dirname, '..' ) );
-} catch ( ex ) {
-}
-
 var less = {
-    version: [1, 1, 3],
-    Parser: require('less/parser').Parser,
-    importer: require('less/parser').importer,
-    tree: require('less/tree'),
+    version: [1, 3, 3],
+    Parser: require('./parser').Parser,
+    importer: require('./parser').importer,
+    tree: require('./tree'),
     render: function (input, options, callback) {
         options = options || {};
 
@@ -20,12 +16,12 @@ var less = {
             callback = options, options = {};
         }
 
-        var parser = new(this.Parser)(options),
+        var parser = new(less.Parser)(options),
             ee;
 
         if (callback) {
             parser.parse(input, function (e, root) {
-                callback(e, root.toCSS(options));
+                callback(e, root && root.toCSS && root.toCSS(options));
             });
         } else {
             ee = new(require('events').EventEmitter);
@@ -39,105 +35,182 @@ var less = {
             return ee;
         }
     },
-    writeError: function (ctx, options) {
+    formatError: function(ctx, options) {
+        options = options || {};
+
         var message = "";
         var extract = ctx.extract;
         var error = [];
-        var stylize = options.color ? less.stylize : function (str) { return str };
+        var stylize = options.color ? require('./lessc_helper').stylize : function (str) { return str };
 
-        options = options || {};
-
-        if (options.silent) { return }
+        // only output a stack if it isn't a less error
+        if (ctx.stack && !ctx.type) { return stylize(ctx.stack, 'red') }
 
-        if (!ctx.index) {
-            return sys.error(ctx.stack || ctx.message);
+        if (!ctx.hasOwnProperty('index') || !extract) {
+            return ctx.stack || ctx.message;
         }
 
         if (typeof(extract[0]) === 'string') {
             error.push(stylize((ctx.line - 1) + ' ' + extract[0], 'grey'));
         }
 
-        error.push(ctx.line + ' ' + extract[1].slice(0, ctx.column)
-                            + stylize(stylize(extract[1][ctx.column], 'bold')
-                            + extract[1].slice(ctx.column + 1), 'yellow'));
+        if (extract[1]) {
+            error.push(ctx.line + ' ' + extract[1].slice(0, ctx.column)
+                                + stylize(stylize(stylize(extract[1][ctx.column], 'bold')
+                                + extract[1].slice(ctx.column + 1), 'red'), 'inverse'));
+        }
 
         if (typeof(extract[2]) === 'string') {
             error.push(stylize((ctx.line + 1) + ' ' + extract[2], 'grey'));
         }
-        error = error.join('\n') + '\033[0m\n';
+        error = error.join('\n') + stylize('', 'reset') + '\n';
 
-        message += stylize(ctx.message, 'red');
-        ctx.filename && (message += stylize(' in ', 'red') + ctx.filename);
+        message += stylize(ctx.type + 'Error: ' + ctx.message, 'red');
+        ctx.filename && (message += stylize(' in ', 'red') + ctx.filename +
+                stylize(':' + ctx.line + ':' + ctx.column, 'grey'));
 
-        sys.error(message, error);
+        message += '\n' + error;
 
         if (ctx.callLine) {
-            sys.error(stylize('from ', 'red')       + (ctx.filename || ''));
-            sys.error(stylize(ctx.callLine, 'grey') + ' ' + ctx.callExtract);
+            message += stylize('from ', 'red') + (ctx.filename || '') + '/n';
+            message += stylize(ctx.callLine, 'grey') + ' ' + ctx.callExtract + '/n';
         }
-        if (ctx.stack) { sys.error(stylize(ctx.stack, 'red')) }
+
+        return message;
+    },
+    writeError: function (ctx, options) {
+        options = options || {};
+        if (options.silent) { return }
+        sys.error(less.formatError(ctx, options));
     }
 };
 
-['color',    'directive', 'operation',  'dimension',
- 'keyword',  'variable',  'ruleset',    'element',
- 'selector', 'quoted',    'expression', 'rule',
- 'call',     'url',       'alpha',      'import',
- 'mixin',    'comment',   'anonymous',  'value', 'javascript'
+['color',      'directive',  'operation',  'dimension',
+ 'keyword',    'variable',   'ruleset',    'element',
+ 'selector',   'quoted',     'expression', 'rule',
+ 'call',       'url',        'alpha',      'import',
+ 'mixin',      'comment',    'anonymous',  'value',
+ 'javascript', 'assignment', 'condition',  'paren',
+ 'media',      'ratio',      'unicode-descriptor'
 ].forEach(function (n) {
-    require(path.join('less', 'tree', n));
+    require('./tree/' + n);
 });
 
-less.Parser.importer = function (file, paths, callback) {
-    var pathname;
 
-    paths.unshift('.');
+var isUrlRe = /^(?:https?:)?\/\//i;
+
+less.Parser.importer = function (file, paths, callback, env) {
+    var pathname, dirname, data;
 
-    for (var i = 0; i < paths.length; i++) {
-        try {
-            pathname = path.join(paths[i], file);
-            fs.statSync(pathname);
-            break;
-        } catch (e) {
-            pathname = null;
+    function parseFile(e, data) {
+        if (e) return callback(e);
+        
+        var rootpath = env.rootpath,
+            j = file.lastIndexOf('/');
+
+        // Pass on an updated rootpath if path of imported file is relative and file 
+        // is in a (sub|sup) directory
+        // 
+        // Examples: 
+        // - If path of imported file is 'module/nav/nav.less' and rootpath is 'less/',
+        //   then rootpath should become 'less/module/nav/'
+        // - If path of imported file is '../mixins.less' and rootpath is 'less/', 
+        //   then rootpath should become 'less/../'
+        if(env.relativeUrls && !/^(?:[a-z-]+:|\/)/.test(file) && j != -1) {
+            rootpath = rootpath + file.slice(0, j+1); // append (sub|sup) directory path of imported file
         }
-    }
 
-    if (pathname) {
-        fs.readFile(pathname, 'utf-8', function(e, data) {
-          if (e) sys.error(e);
-
-          new(less.Parser)({
-              paths: [path.dirname(pathname)].concat(paths),
-              filename: pathname
-          }).parse(data, function (e, root) {
-              if (e) less.writeError(e);
-              callback(root);
-          });
+        env.contents[pathname] = data;      // Updating top importing parser content cache.
+        new(less.Parser)({
+                paths: [dirname].concat(paths),
+                filename: pathname,
+                contents: env.contents,
+                files: env.files,
+                syncImport: env.syncImport,
+                relativeUrls: env.relativeUrls,
+                rootpath: rootpath,
+                dumpLineNumbers: env.dumpLineNumbers
+        }).parse(data, function (e, root) {
+            callback(e, root, pathname);
         });
+    };
+    
+    var isUrl = isUrlRe.test( file );
+    if (isUrl || isUrlRe.test(paths[0])) {
+
+        var urlStr = isUrl ? file : url.resolve(paths[0], file),
+            urlObj = url.parse(urlStr),
+            req = {
+                host:   urlObj.hostname,
+                port:   urlObj.port || 80,
+                path:   urlObj.pathname + (urlObj.search||'')
+            };
+
+        http.get(req, function (res) {
+            var body = '';
+            res.on('data', function (chunk) {
+                body += chunk.toString();
+            });
+            res.on('end', function () {
+                if (res.statusCode === 404) {
+                    callback({ type: 'File', message: "resource '" + urlStr + "' was not found\n" });
+                }
+                if (!body) {
+                    sys.error( 'Warning: Empty body (HTTP '+ res.statusCode + ') returned by "' + urlStr +'"' );
+                }
+                pathname = urlStr;
+                dirname = urlObj.protocol +'//'+ urlObj.host + urlObj.pathname.replace(/[^\/]*$/, '');
+                parseFile(null, body);
+            });
+        }).on('error', function (err) {
+            callback({ type: 'File', message: "resource '" + urlStr + "' gave this Error:\n  "+ err +"\n" });
+        });
+
     } else {
-        sys.error("file '" + file + "' wasn't found.\n");
-        process.exit(1);
-    }
-}
 
-require('less/functions');
+        // TODO: Undo this at some point,
+        // or use different approach.
+        var paths = [].concat(paths);
+        paths.push('.');
+
+        for (var i = 0; i < paths.length; i++) {
+            try {
+                pathname = path.join(paths[i], file);
+                fs.statSync(pathname);
+                break;
+            } catch (e) {
+                pathname = null;
+            }
+        }
+        
+        paths = paths.slice(0, paths.length - 1);
 
-for (var k in less) { exports[k] = less[k] }
+        if (!pathname) {
 
-// Stylize a string
-function stylize(str, style) {
-    var styles = {
-        'bold'      : [1,  22],
-        'inverse'   : [7,  27],
-        'underline' : [4,  24],
-        'yellow'    : [33, 39],
-        'green'     : [32, 39],
-        'red'       : [31, 39],
-        'grey'      : [90, 39]
-    };
-    return '\033[' + styles[style][0] + 'm' + str +
-           '\033[' + styles[style][1] + 'm';
+            if (typeof(env.errback) === "function") {
+                env.errback(file, paths, callback);
+            } else {
+                callback({ type: 'File', message: "'" + file + "' wasn't found.\n" });
+            }
+            return;
+        }
+        
+        dirname = path.dirname(pathname);
+
+        if (env.syncImport) {
+            try {
+                data = fs.readFileSync(pathname, 'utf-8');
+                parseFile(null, data);
+            } catch (e) {
+                parseFile(e);
+            }
+        } else {
+            fs.readFile(pathname, 'utf-8', parseFile);
+        }
+    }
 }
-less.stylize = stylize;
 
+require('./functions');
+require('./colors');
+
+for (var k in less) { exports[k] = less[k] }
diff --git a/build-tools/lib/less/lessc_helper.js b/build-tools/lib/less/lessc_helper.js
new file mode 100644
index 0000000..1a82ef9
--- /dev/null
+++ b/build-tools/lib/less/lessc_helper.js
@@ -0,0 +1,62 @@
+// lessc_helper.js
+//
+//      helper functions for lessc
+sys = require('util');
+
+var lessc_helper = {
+
+    //Stylize a string
+    stylize : function(str, style) {
+        var styles = {
+            'reset'     : [0,   0],
+            'bold'      : [1,  22],
+            'inverse'   : [7,  27],
+            'underline' : [4,  24],
+            'yellow'    : [33, 39],
+            'green'     : [32, 39],
+            'red'       : [31, 39],
+            'grey'      : [90, 39]
+        };
+        return '\033[' + styles[style][0] + 'm' + str +
+               '\033[' + styles[style][1] + 'm';
+    },
+
+    //Print command line options
+    printUsage: function() {
+        sys.puts("usage: lessc [option option=parameter ...] <source> [destination]");
+        sys.puts("");
+        sys.puts("If source is set to `-' (dash or hyphen-minus), input is read from stdin.");
+        sys.puts("");
+        sys.puts("options:");
+        sys.puts("  -h, --help              Print help (this message) and exit.");
+        sys.puts("  --include-path          Set include paths. Separated by `:'. Use `;' on Windows.");
+        sys.puts("  --no-color              Disable colorized output.");
+        sys.puts("  -s, --silent            Suppress output of error messages.");
+        sys.puts("  --strict-imports        Force evaluation of imports.");
+        sys.puts("  --verbose               Be verbose.");
+        sys.puts("  -v, --version           Print version number and exit.");
+        sys.puts("  -x, --compress          Compress output by removing some whitespaces.");
+        sys.puts("  --yui-compress          Compress output using ycssmin");
+        sys.puts("  -O0, -O1, -O2           Set the parser's optimization level. The lower");
+        sys.puts("                          the number, the less nodes it will create in the");
+        sys.puts("                          tree. This could matter for debugging, or if you");
+        sys.puts("                          want to access the individual nodes in the tree.");
+        sys.puts("  --line-numbers=TYPE     Outputs filename and line numbers.");
+        sys.puts("                          TYPE can be either 'comments', which will output");
+        sys.puts("                          the debug info within comments, 'mediaquery'");
+        sys.puts("                          that will output the information within a fake");
+        sys.puts("                          media query which is compatible with the SASS");
+        sys.puts("                          format, and 'all' which will do both.");
+        sys.puts("  -rp, --rootpath         Set rootpath for url rewriting in relative imports and urls.");
+        sys.puts("                          Works with or withour the relative-urls option.");
+        sys.puts("  -ru, --relative-urls    re-write relative urls to the base less file.");
+        sys.puts("");
+        sys.puts("Report bugs to: http://github.com/cloudhead/less.js/issues");
+        sys.puts("Home page: <http://lesscss.org/>");
+    }
+
+
+}
+
+// Exports helper functions
+for (var h in lessc_helper) { exports[h] = lessc_helper[h] }
diff --git a/build-tools/lib/less/parser.js b/build-tools/lib/less/parser.js
index fae248e..c8c280b 100644
--- a/build-tools/lib/less/parser.js
+++ b/build-tools/lib/less/parser.js
@@ -1,16 +1,17 @@
-var less, tree;
+var less, tree, charset;
 
 if (typeof environment === "object" && ({}).toString.call(environment) === "[object Environment]") {
     // Rhino
     // Details on how to detect Rhino: https://github.com/ringo/ringojs/issues/88
-    less = {};
+    if (typeof(window) === 'undefined') { less = {} }
+    else                                { less = window.less = {} }
     tree = less.tree = {};
     less.mode = 'rhino';
 } else if (typeof(window) === 'undefined') {
     // Node.js
     less = exports,
-    tree = require('less/tree');
-    less.mode = 'rhino';
+    tree = require('./tree');
+    less.mode = 'node';
 } else {
     // Browser
     if (typeof(window.less) === 'undefined') { window.less = {} }
@@ -64,15 +65,25 @@ less.Parser = function Parser(env) {
 
     var that = this;
 
+    // Top parser on an import tree must be sure there is one "env"
+    // which will then be passed arround by reference.
+    var env = env || { };
+    // env.contents and files must be passed arround with top env
+    if (!env.contents) { env.contents = {}; }
+    env.rootpath = env.rootpath || '';       // env.rootpath must be initialized to '' if not provided
+    if (!env.files) { env.files = {}; }
+
     // This function is called after all files
     // have been imported through `@import`.
     var finish = function () {};
 
     var imports = this.imports = {
-        paths: env && env.paths || [],  // Search paths, when importing
-        queue: [],                      // Files which haven't been imported yet
-        files: {},                      // Holds the imported parse trees
-        mime:  env && env.mime,         // MIME type of .less files
+        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
+        mime:  env.mime,         // MIME type of .less files
+        error: null,             // Error in parsing/evaluating an import
         push: function (path, callback) {
             var that = this;
             this.queue.push(path);
@@ -80,13 +91,18 @@ less.Parser = function Parser(env) {
             //
             // Import a file asynchronously
             //
-            less.Parser.importer(path, this.paths, function (root) {
+            less.Parser.importer(path, this.paths, function (e, root, fullPath) {
                 that.queue.splice(that.queue.indexOf(path), 1); // Remove the path from the queue
-                that.files[path] = root;                        // Store the root
 
-                callback(root);
+                var imported = fullPath in that.files;
+
+                that.files[fullPath] = root;                        // Store the root
 
-                if (that.queue.length === 0) { finish() }       // Call `finish` if we're done importing
+                if (e && !that.error) { that.error = e }
+
+                callback(e, root, imported);
+
+                if (that.queue.length === 0) { finish(that.error) }       // Call `finish` if we're done importing
             }, env);
         }
     };
@@ -100,11 +116,16 @@ less.Parser = function Parser(env) {
             current = i;
         }
     }
+    function isWhitespace(c) {
+        // Could change to \s?
+        var code = c.charCodeAt(0);
+        return code === 32 || code === 10 || code === 9;
+    }
     //
     // Parse from a token, regexp or string, and move forward if match
     //
     function $(tok) {
-        var match, args, length, c, index, endIndex, k, mem;
+        var match, args, length, index, k;
 
         //
         // Non-terminal
@@ -137,18 +158,7 @@ less.Parser = function Parser(env) {
         // grammar is mostly white-space insensitive.
         //
         if (match) {
-            mem = i += length;
-            endIndex = i + chunks[j].length - length;
-
-            while (i < endIndex) {
-                c = input.charCodeAt(i);
-                if (! (c === 32 || c === 10 || c === 9)) { break }
-                i++;
-            }
-            chunks[j] = chunks[j].slice(length + (i - mem));
-            current = i;
-
-            if (chunks[j].length === 0 && j < chunks.length - 1) { j++ }
+            skipWhitespace(length);
 
             if(typeof(match) === 'string') {
                 return match;
@@ -158,6 +168,40 @@ less.Parser = function Parser(env) {
         }
     }
 
+    function skipWhitespace(length) {
+        var oldi = i, oldj = j,
+            endIndex = i + chunks[j].length,
+            mem = i += length;
+
+        while (i < endIndex) {
+            if (! isWhitespace(input.charAt(i))) { break }
+            i++;
+        }
+        chunks[j] = chunks[j].slice(length + (i - mem));
+        current = i;
+
+        if (chunks[j].length === 0 && j < chunks.length - 1) { j++ }
+
+        return oldi !== i || oldj !== j;
+    }
+
+    function expect(arg, msg) {
+        var result = $(arg);
+        if (! result) {
+            error(msg || (typeof(arg) === 'string' ? "expected '" + arg + "' got '" + input.charAt(i) + "'"
+                                                   : "unexpected token"));
+        } else {
+            return result;
+        }
+    }
+
+    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) {
@@ -172,6 +216,60 @@ less.Parser = function Parser(env) {
         }
     }
 
+    function getInput(e, env) {
+        if (e.filename && env.filename && (e.filename !== env.filename)) {
+            return parser.imports.contents[e.filename];
+        } else {
+            return input;
+        }
+    }
+
+    function getLocation(index, input) {
+        for (var n = index, column = -1;
+                 n >= 0 && input.charAt(n) !== '\n';
+                 n--) { column++ }
+
+        return { line:   typeof(index) === 'number' ? (input.slice(0, index).match(/\n/g) || "").length : null,
+                 column: column };
+    }
+
+    function getFileName(e) {
+        if(less.mode === 'browser' || less.mode === 'rhino')
+            return e.filename;
+        else
+            return require('path').resolve(e.filename);
+    }
+
+    function getDebugInfo(index, inputStream, e) {
+        return {
+            lineNumber: getLocation(index, inputStream).line + 1,
+            fileName: getFileName(e)
+        };
+    }
+
+    function LessError(e, env) {
+        var input = getInput(e, env),
+            loc = getLocation(e.index, input),
+            line = loc.line,
+            col  = loc.column,
+            lines = input.split('\n');
+
+        this.type = e.type || 'Syntax';
+        this.message = e.message;
+        this.filename = e.filename || env.filename;
+        this.index = e.index;
+        this.line = typeof(line) === 'number' ? line + 1 : null;
+        this.callLine = e.call && (getLocation(e.call, input).line + 1);
+        this.callExtract = lines[getLocation(e.call, input).line];
+        this.stack = e.stack;
+        this.column = col;
+        this.extract = [
+            lines[line - 1],
+            lines[line],
+            lines[line + 1]
+        ];
+    }
+
     this.env = env = env || {};
 
     // The optimization level dictates the thoroughness of the parser,
@@ -196,21 +294,23 @@ less.Parser = function Parser(env) {
             var root, start, end, zone, line, lines, buff = [], c, error = null;
 
             i = j = current = furthest = 0;
-            chunks = [];
             input = str.replace(/\r\n/g, '\n');
 
+            // Remove potential UTF Byte Order Mark
+            input = input.replace(/^\uFEFF/, '');
+
             // Split the input into chunks.
             chunks = (function (chunks) {
                 var j = 0,
-                    skip = /[^"'`\{\}\/\(\)]+/g,
+                    skip = /(?:@\{[\w-]+\}|[^"'`\{\}\/\(\)\\])+/g,
                     comment = /\/\*(?:[^*]|\*+[^\/*])*\*+\/|\/\/.*/g,
+                    string = /"((?:[^"\\\r\n]|\\.)*)"|'((?:[^'\\\r\n]|\\.)*)'|`((?:[^`]|\\.)*)`/g,
                     level = 0,
                     match,
                     chunk = chunks[0],
-                    inParam,
-                    inString;
+                    inParam;
 
-                for (var i = 0, c, cc; i < input.length; i++) {
+                for (var i = 0, c, cc; i < input.length;) {
                     skip.lastIndex = i;
                     if (match = skip.exec(input)) {
                         if (match.index === i) {
@@ -219,66 +319,71 @@ less.Parser = function Parser(env) {
                         }
                     }
                     c = input.charAt(i);
-                    comment.lastIndex = i;
+                    comment.lastIndex = string.lastIndex = i;
+
+                    if (match = string.exec(input)) {
+                        if (match.index === i) {
+                            i += match[0].length;
+                            chunk.push(match[0]);
+                            continue;
+                        }
+                    }
 
-                    if (!inString && !inParam && c === '/') {
+                    if (!inParam && c === '/') {
                         cc = input.charAt(i + 1);
                         if (cc === '/' || cc === '*') {
                             if (match = comment.exec(input)) {
                                 if (match.index === i) {
                                     i += match[0].length;
                                     chunk.push(match[0]);
-                                    c = input.charAt(i);
+                                    continue;
                                 }
                             }
                         }
                     }
-
-                    if        (c === '{' && !inString && !inParam) { level ++;
-                        chunk.push(c);
-                    } else if (c === '}' && !inString && !inParam) { level --;
-                        chunk.push(c);
-                        chunks[++j] = chunk = [];
-                    } else if (c === '(' && !inString && !inParam) {
-                        chunk.push(c);
-                        inParam = true;
-                    } else if (c === ')' && !inString && inParam) {
-                        chunk.push(c);
-                        inParam = false;
-                    } else {
-                        if (c === '"' || c === "'" || c === '`') {
-                            if (! inString) {
-                                inString = c;
-                            } else {
-                                inString = inString === c ? false : inString;
-                            }
-                        }
-                        chunk.push(c);
+                    
+                    switch (c) {
+                        case '{': if (! inParam) { level ++;        chunk.push(c);                           break }
+                        case '}': if (! inParam) { level --;        chunk.push(c); chunks[++j] = chunk = []; break }
+                        case '(': if (! inParam) { inParam = true;  chunk.push(c);                           break }
+                        case ')': if (  inParam) { inParam = false; chunk.push(c);                           break }
+                        default:                                    chunk.push(c);
                     }
+                    
+                    i++;
                 }
-                if (level > 0) {
-                    throw {
-                        type: 'Syntax',
-                        message: "Missing closing `}`",
+                if (level != 0) {
+                    error = new(LessError)({
+                        index: i-1,
+                        type: 'Parse',
+                        message: (level > 0) ? "missing closing `}`" : "missing opening `{`",
                         filename: env.filename
-                    };
+                    }, env);
                 }
 
                 return chunks.map(function (c) { return c.join('') });;
             })([[]]);
 
+            if (error) {
+                return callback(error, env);
+            }
+
             // 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.
-            root = new(tree.Ruleset)([], $(this.parsers.primary));
-            root.root = true;
+            try {
+                root = new(tree.Ruleset)([], $(this.parsers.primary));
+                root.root = true;
+            } catch (e) {
+                return callback(new(LessError)(e, env));
+            }
 
             root.toCSS = (function (evaluate) {
                 var line, lines, column;
 
                 return function (options, variables) {
-                    var frames = [];
+                    var frames = [], importError;
 
                     options = options || {};
                     //
@@ -311,41 +416,23 @@ less.Parser = function Parser(env) {
 
                     try {
                         var css = evaluate.call(this, { frames: frames })
-                                          .toCSS([], { compress: options.compress || false });
+                                          .toCSS([], { compress: options.compress || false, dumpLineNumbers: env.dumpLineNumbers });
                     } catch (e) {
-                        lines = input.split('\n');
-                        line = getLine(e.index);
-
-                        for (var n = e.index, column = -1;
-                                 n >= 0 && input.charAt(n) !== '\n';
-                                 n--) { column++ }
-
-                        throw {
-                            type: e.type,
-                            message: e.message,
-                            filename: env.filename,
-                            index: e.index,
-                            line: typeof(line) === 'number' ? line + 1 : null,
-                            callLine: e.call && (getLine(e.call) + 1),
-                            callExtract: lines[getLine(e.call)],
-                            stack: e.stack,
-                            column: column,
-                            extract: [
-                                lines[line - 1],
-                                lines[line],
-                                lines[line + 1]
-                            ]
-                        };
+                        throw new(LessError)(e, env);
                     }
-                    if (options.compress) {
+
+                    if ((importError = parser.imports.error)) { // Check if there was an error during importing
+                        if (importError instanceof LessError) throw importError;
+                        else                                  throw new(LessError)(importError, env);
+                    }
+
+                    if (options.yuicompress && less.mode === 'node') {
+                        return require('ycssmin').cssmin(css);
+                    } else if (options.compress) {
                         return css.replace(/(\s)+/g, "$1");
                     } else {
                         return css;
                     }
-
-                    function getLine(index) {
-                        return index ? (input.slice(0, index).match(/\n/g) || "").length : null;
-                    }
                 };
             })(root.eval);
 
@@ -365,7 +452,7 @@ less.Parser = function Parser(env) {
                 for (var n = i, column = -1; n >= 0 && input.charAt(n) !== '\n'; n--) { column++ }
 
                 error = {
-                    name: "ParseError",
+                    type: "Parse",
                     message: "Syntax Error on line " + line,
                     index: i,
                     filename: env.filename,
@@ -380,7 +467,11 @@ less.Parser = function Parser(env) {
             }
 
             if (this.imports.queue.length > 0) {
-                finish = function () { callback(error, root) };
+                finish = function (e) {
+                    e = error || e;
+                    if (e) callback(e);
+                    else callback(null, root);
+                };
             } else {
                 callback(error, root);
             }
@@ -436,7 +527,7 @@ less.Parser = function Parser(env) {
 
                 while ((node = $(this.mixin.definition) || $(this.rule)    ||  $(this.ruleset) ||
                                $(this.mixin.call)       || $(this.comment) ||  $(this.directive))
-                               || $(/^[\s\n]+/)) {
+                               || $(/^[\s\n]+/) || $(/^;+/)) {
                     node && root.push(node);
                 }
                 return root;
@@ -486,7 +577,15 @@ less.Parser = function Parser(env) {
                 //
                 keyword: function () {
                     var k;
-                    if (k = $(/^[_A-Za-z-][_A-Za-z0-9-]*/)) { return new(tree.Keyword)(k) }
+
+                    if (k = $(/^[_A-Za-z-][_A-Za-z0-9-]*/)) {
+                        if (tree.colors.hasOwnProperty(k)) {
+                            // detect named color
+                            return new(tree.Color)(tree.colors[k].slice(1));
+                        } else {
+                            return new(tree.Keyword)(k);
+                        }
+                    }
                 },
 
                 //
@@ -500,16 +599,22 @@ less.Parser = function Parser(env) {
                 // The arguments are parsed with the `entities.arguments` parser.
                 //
                 call: function () {
-                    var name, args, index = i;
+                    var name, nameLC, args, alpha_ret, index = i;
 
-                    if (! (name = /^([\w-]+|%)\(/.exec(chunks[j]))) return;
+                    if (! (name = /^([\w-]+|%|progid:[\w\.]+)\(/.exec(chunks[j]))) return;
 
-                    name = name[1].toLowerCase();
+                    name = name[1];
+                    nameLC = name.toLowerCase();
 
-                    if (name === 'url') { return null }
+                    if (nameLC === 'url') { return null }
                     else                { i += name.length }
 
-                    if (name === 'alpha') { return $(this.alpha) }
+                    if (nameLC === 'alpha') {
+                        alpha_ret = $(this.alpha);
+                        if(typeof alpha_ret !== 'undefined') {
+                            return alpha_ret;
+                        }
+                    }
 
                     $('('); // Parse the '(' and consume whitespace.
 
@@ -517,21 +622,36 @@ less.Parser = function Parser(env) {
 
                     if (! $(')')) return;
 
-                    if (name) { return new(tree.Call)(name, args, index) }
+                    if (name) { return new(tree.Call)(name, args, index, env.filename) }
                 },
                 arguments: function () {
                     var args = [], arg;
 
-                    while (arg = $(this.expression)) {
+                    while (arg = $(this.entities.assignment) || $(this.expression)) {
                         args.push(arg);
                         if (! $(',')) { break }
                     }
                     return args;
                 },
                 literal: function () {
-                    return $(this.entities.dimension) ||
+                    return $(this.entities.ratio) ||
+                           $(this.entities.dimension) ||
                            $(this.entities.color) ||
-                           $(this.entities.quoted);
+                           $(this.entities.quoted) ||
+                           $(this.entities.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;
+                    if ((key = $(/^\w+(?=\s?=)/i)) && $('=') && (value = $(this.entity))) {
+                        return new(tree.Assignment)(key, value);
+                    }
                 },
 
                 //
@@ -546,25 +666,12 @@ less.Parser = function Parser(env) {
 
                     if (input.charAt(i) !== 'u' || !$(/^url\(/)) return;
                     value = $(this.entities.quoted)  || $(this.entities.variable) ||
-                            $(this.entities.dataURI) || $(/^[-\w%@$\/.&=:;#+?~]+/) || "";
-                    if (! $(')')) throw new(Error)("missing closing ) for url()");
-
-                    return new(tree.URL)((value.value || value.data || value instanceof tree.Variable)
-                                        ? value : new(tree.Anonymous)(value), imports.paths);
-                },
+                            $(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || "";
 
-                dataURI: function () {
-                    var obj;
+                    expect(')');
 
-                    if ($(/^data:/)) {
-                        obj         = {};
-                        obj.mime    = $(/^[^\/]+\/[^,;)]+/)     || '';
-                        obj.charset = $(/^;\s*charset=[^,;)]+/) || '';
-                        obj.base64  = $(/^;\s*base64/)          || '';
-                        obj.data    = $(/^,\s*[^)]+/);
-
-                        if (obj.data) { return obj }
-                    }
+                    return new(tree.URL)((value.value != null || value instanceof tree.Variable)
+                                        ? value : new(tree.Anonymous)(value), env.rootpath);
                 },
 
                 //
@@ -579,7 +686,16 @@ less.Parser = function Parser(env) {
                     var name, index = i;
 
                     if (input.charAt(i) === '@' && (name = $(/^@@?[\w-]+/))) {
-                        return new(tree.Variable)(name, index);
+                        return new(tree.Variable)(name, index, env.filename);
+                    }
+                },
+
+                // A variable entity useing the protective {} e.g. @{var}
+                variableCurly: function () {
+                    var name, curly, index = i;
+
+                    if (input.charAt(i) === '@' && (curly = $(/^@\{([\w-]+)\}/))) {
+                        return new(tree.Variable)("@" + curly[1], index, env.filename);
                     }
                 },
 
@@ -593,7 +709,7 @@ less.Parser = function Parser(env) {
                 color: function () {
                     var rgb;
 
-                    if (input.charAt(i) === '#' && (rgb = $(/^#([a-fA-F0-9]{6}|[a-fA-F0-9]{3})/))) {
+                    if (input.charAt(i) === '#' && (rgb = $(/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/))) {
                         return new(tree.Color)(rgb[1]);
                     }
                 },
@@ -605,14 +721,42 @@ less.Parser = function Parser(env) {
                 //
                 dimension: function () {
                     var value, c = input.charCodeAt(i);
-                    if ((c > 57 || c < 45) || c === 47) return;
+                    //Is the first char of the dimension 0-9, '.', '+' or '-'
+                    if ((c > 57 || c < 43) || c === 47 || c == 44) return;
 
-                    if (value = $(/^(-?\d*\.?\d+)(px|%|em|rem|pc|ex|in|deg|s|ms|pt|cm|mm|rad|grad|turn)?/)) {
+                    if (value = $(/^([+-]?\d*\.?\d+)(px|%|em|pc|ex|in|deg|s|ms|pt|cm|mm|rad|grad|turn|dpi|dpcm|dppx|rem|vw|vh|vmin|vm|ch)?/)) {
                         return new(tree.Dimension)(value[1], value[2]);
                     }
                 },
 
                 //
+                // A Ratio
+                //
+                //    16/9
+                //
+                ratio: function () {
+                  var value, c = input.charCodeAt(i);
+                  if (c > 57 || c < 48) return;
+
+                  if (value = $(/^(\d+\/\d+)/)) {
+                    return new(tree.Ratio)(value[1]);
+                  }
+                },
+                
+                //
+                // A unicode descriptor, as is used in unicode-range
+                //
+                // U+0??  or U+00A1-00A9
+                //
+                unicodeDescriptor: function () {
+                    var ud;
+                    
+                    if (ud = $(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/)) {
+                        return new(tree.UnicodeDescriptor)(ud[0]);
+                    }
+                },
+
+                //
                 // JavaScript code to be evaluated
                 //
                 //     `window.location.href`
@@ -654,9 +798,13 @@ less.Parser = function Parser(env) {
 
                 if (! peek(/^[@\w.%-]+\/[@\w.-]+/)) return;
 
+                save();
+
                 if ((a = $(this.entity)) && $('/') && (b = $(this.entity))) {
                     return new(tree.Shorthand)(a, b);
                 }
+
+                restore();
             },
 
             //
@@ -675,19 +823,80 @@ less.Parser = function Parser(env) {
                 // selector for now.
                 //
                 call: function () {
-                    var elements = [], e, c, args, index = i, s = input.charAt(i);
+                    var elements = [], e, c, argsSemiColon = [], argsComma = [], args, delim, arg, nameLoop, expressions, isSemiColonSeperated, expressionContainsNamed, index = i, s = input.charAt(i), name, value, important = false;
 
                     if (s !== '.' && s !== '#') { return }
+                    
+                    save(); // stop us absorbing part of an invalid selector
 
-                    while (e = $(/^[#.](?:[\w-]|\\(?:[a-fA-F0-9]{1,6} ?|[^a-fA-F0-9]))+/)) {
-                        elements.push(new(tree.Element)(c, e));
+                    while (e = $(/^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/)) {
+                        elements.push(new(tree.Element)(c, e, i));
                         c = $('>');
                     }
-                    $('(') && (args = $(this.entities.arguments)) && $(')');
+                    if ($('(')) {
+                        expressions = [];
+                        while (arg = $(this.expression)) {
+                            nameLoop = null;
+                            value = arg;
+
+                            // Variable
+                            if (arg.value.length == 1) {
+                                var val = arg.value[0];
+                                if (val instanceof tree.Variable) {
+                                    if ($(':')) {
+                                        if (expressions.length > 0) {
+                                            if (isSemiColonSeperated) {
+                                                error("Cannot mix ; and , as delimiter types");
+                                            }
+                                            expressionContainsNamed = true;
+                                        }
+                                        value = expect(this.expression);
+                                        nameLoop = (name = val.name);
+                                    }
+                                }
+                            }
+                            
+                            expressions.push(value);
+                            
+                            argsComma.push({ name: nameLoop, value: value });
+                            
+                            if ($(',')) {
+                                continue;
+                            }
+                            
+                            if ($(';') || 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;
+                            }
+                        }
+
+                        expect(')');
+                    }
+
+                    args = isSemiColonSeperated ? argsSemiColon : argsComma;
+
+                    if ($(this.important)) {
+                        important = true;
+                    }
 
                     if (elements.length > 0 && ($(';') || peek('}'))) {
-                        return new(tree.mixin.Call)(elements, args, index);
+                        return new(tree.mixin.Call)(elements, args, index, env.filename, important);
                     }
+                    
+                    restore();
                 },
 
                 //
@@ -710,38 +919,62 @@ less.Parser = function Parser(env) {
                 // the `{...}` block.
                 //
                 definition: function () {
-                    var name, params = [], match, ruleset, param, value;
-
+                    var name, params = [], match, ruleset, param, value, cond, variadic = false;
                     if ((input.charAt(i) !== '.' && input.charAt(i) !== '#') ||
-                        peek(/^[^{]*(;|})/)) return;
+                        peek(/^[^{]*\}/)) return;
+
+                    save();
 
-                    if (match = $(/^([#.](?:[\w-]|\\(?:[a-fA-F0-9]{1,6} ?|[^a-fA-F0-9]))+)\s*\(/)) {
+                    if (match = $(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/)) {
                         name = match[1];
 
-                        while (param = $(this.entities.variable) || $(this.entities.literal)
-                                                                 || $(this.entities.keyword)) {
-                            // Variable
-                            if (param instanceof tree.Variable) {
-                                if ($(':')) {
-                                    if (value = $(this.expression)) {
+                        do {
+                            $(this.comment);
+                            if (input.charAt(i) === '.' && $(/^\.{3}/)) {
+                                variadic = true;
+                                params.push({ variadic: true });
+                                break;
+                            } else if (param = $(this.entities.variable) || $(this.entities.literal)
+                                                                         || $(this.entities.keyword)) {
+                                // Variable
+                                if (param instanceof tree.Variable) {
+                                    if ($(':')) {
+                                        value = expect(this.expression, 'expected expression');
                                         params.push({ name: param.name, value: value });
+                                    } else if ($(/^\.{3}/)) {
+                                        params.push({ name: param.name, variadic: true });
+                                        variadic = true;
+                                        break;
                                     } else {
-                                        throw new(Error)("Expected value");
+                                        params.push({ name: param.name });
                                     }
                                 } else {
-                                    params.push({ name: param.name });
+                                    params.push({ value: param });
                                 }
                             } else {
-                                params.push({ value: param });
+                                break;
                             }
-                            if (! $(',')) { break }
+                        } while ($(',') || $(';'))
+
+                        // .mixincall("@{a}"); 
+                        // looks a bit like a mixin definition.. so we have to be nice and restore
+                        if (!$(')')) {
+                            furthest = i;
+                            restore();
+                        }
+                        
+                        $(this.comment);
+
+                        if ($(/^when/)) { // Guard
+                            cond = expect(this.conditions, 'expected condition');
                         }
-                        if (! $(')')) throw new(Error)("Expected )");
 
                         ruleset = $(this.block);
 
                         if (ruleset) {
-                            return new(tree.mixin.Definition)(name, params, ruleset);
+                            return new(tree.mixin.Definition)(name, params, ruleset, cond, variadic);
+                        } else {
+                            restore();
                         }
                     }
                 }
@@ -753,7 +986,7 @@ less.Parser = function Parser(env) {
             //
             entity: function () {
                 return $(this.entities.literal) || $(this.entities.variable) || $(this.entities.url) ||
-                       $(this.entities.call)    || $(this.entities.keyword)  || $(this.entities.javascript) ||
+                       $(this.entities.call)    || $(this.entities.keyword)  ||$(this.entities.javascript) ||
                        $(this.comment);
             },
 
@@ -776,7 +1009,7 @@ less.Parser = function Parser(env) {
 
                 if (! $(/^\(opacity=/i)) return;
                 if (value = $(/^\d+/) || $(this.entities.variable)) {
-                    if (! $(')')) throw new(Error)("missing closing ) for alpha()");
+                    expect(')');
                     return new(tree.Alpha)(value);
                 }
             },
@@ -794,16 +1027,25 @@ less.Parser = function Parser(env) {
             // and an element name, such as a tag a class, or `*`.
             //
             element: function () {
-                var e, t, c;
+                var e, t, c, v;
 
                 c = $(this.combinator);
-                e = $(/^(?:[.#]?|:*)(?:[\w-]|\\(?:[a-fA-F0-9]{1,6} ?|[^a-fA-F0-9]))+/) || $('*') || $(this.attribute) || $(/^\([^)@]+\)/) || $(/^(?:\d*\.)?\d+%/);
 
-                if (e) { return new(tree.Element)(c, e) }
+                e = $(/^(?:\d+\.\d+|\d+)%/) || $(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) ||
+                    $('*') || $('&') || $(this.attribute) || $(/^\([^()@]+\)/) || $(/^[\.#](?=@)/) || $(this.entities.variableCurly);
 
-                if (c.value && c.value[0] === '&') {
-                  return new(tree.Element)(c, null);
+                if (! e) {
+                    if ($('(')) {
+                        if ((v = ($(this.entities.variableCurly) || 
+                                $(this.entities.variable) || 
+                                $(this.selector))) && 
+                                $(')')) {
+                            e = new(tree.Paren)(v);
+                        }
+                    }
                 }
+
+                if (e) { return new(tree.Element)(c, e, i) }
             },
 
             //
@@ -818,23 +1060,11 @@ less.Parser = function Parser(env) {
             combinator: function () {
                 var match, c = input.charAt(i);
 
-                if (c === '>' || c === '+' || c === '~') {
+                if (c === '>' || c === '+' || c === '~' || c === '|') {
                     i++;
-                    while (input.charAt(i) === ' ') { i++ }
+                    while (input.charAt(i).match(/\s/)) { i++ }
                     return new(tree.Combinator)(c);
-                } else if (c === '&') {
-                    match = '&';
-                    i++;
-                    if(input.charAt(i) === ' ') {
-                        match = '& ';
-                    }
-                    while (input.charAt(i) === ' ') { i++ }
-                    return new(tree.Combinator)(match);
-                } else if (c === ':' && input.charAt(i + 1) === ':') {
-                    i += 2;
-                    while (input.charAt(i) === ' ') { i++ }
-                    return new(tree.Combinator)('::');
-                } else if (input.charAt(i - 1) === ' ') {
+                } else if (input.charAt(i - 1).match(/\s/)) {
                     return new(tree.Combinator)(" ");
                 } else {
                     return new(tree.Combinator)(null);
@@ -852,23 +1082,27 @@ less.Parser = function Parser(env) {
             selector: function () {
                 var sel, e, elements = [], c, match;
 
+                // depreciated, will be removed soon
+                if ($('(')) {
+                    sel = $(this.entity);
+                    if (!$(')')) { return null; }
+                    return new(tree.Selector)([new(tree.Element)('', sel, i)]);
+                }
+
                 while (e = $(this.element)) {
                     c = input.charAt(i);
                     elements.push(e)
-                    if (c === '{' || c === '}' || c === ';' || c === ',') { break }
+                    if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') { break }
                 }
 
                 if (elements.length > 0) { return new(tree.Selector)(elements) }
             },
-            tag: function () {
-                return $(/^[a-zA-Z][a-zA-Z-]*[0-9]?/) || $('*');
-            },
             attribute: function () {
                 var attr = '', key, val, op;
 
                 if (! $('[')) return;
 
-                if (key = $(/^[a-zA-Z-]+/) || $(this.entities.quoted)) {
+                if (key = $(/^(?:[_A-Za-z0-9-]|\\.)+/) || $(this.entities.quoted)) {
                     if ((op = $(/^[|~*$^]?=/)) &&
                         (val = $(this.entities.quoted) || $(/^[\w-]+/))) {
                         attr = [key, op, val.toCSS ? val.toCSS() : val].join('');
@@ -886,7 +1120,6 @@ less.Parser = function Parser(env) {
             //
             block: function () {
                 var content;
-
                 if ($('{') && (content = $(this.primary)) && $('}')) {
                     return content;
                 }
@@ -896,9 +1129,13 @@ less.Parser = function Parser(env) {
             // div, .class, body > p {...}
             //
             ruleset: function () {
-                var selectors = [], s, rules, match;
+                var selectors = [], s, rules, match, debugInfo;
+                
                 save();
 
+                if (env.dumpLineNumbers)
+                    debugInfo = getDebugInfo(i, input, env);
+
                 while (s = $(this.selector)) {
                     selectors.push(s);
                     $(this.comment);
@@ -907,7 +1144,10 @@ less.Parser = function Parser(env) {
                 }
 
                 if (selectors.length > 0 && (rules = $(this.block))) {
-                    return new(tree.Ruleset)(selectors, rules);
+                    var ruleset = new(tree.Ruleset)(selectors, rules, env.strictImports);
+                    if (env.dumpLineNumbers)
+                        ruleset.debugInfo = debugInfo;
+                    return ruleset;
                 } else {
                     // Backtrack
                     furthest = i;
@@ -951,11 +1191,79 @@ less.Parser = function Parser(env) {
             // stored in `import`, which we pass to the Import constructor.
             //
             "import": function () {
-                var path;
-                if ($(/^@import\s+/) &&
-                    (path = $(this.entities.quoted) || $(this.entities.url)) &&
-                    $(';')) {
-                    return new(tree.Import)(path, imports);
+                var path, features, index = i;
+                
+                save();
+                
+                var dir = $(/^@import(?:-(once))?\s+/);
+
+                if (dir && (path = $(this.entities.quoted) || $(this.entities.url))) {
+                    features = $(this.mediaFeatures);
+                    if ($(';')) {
+                        return new(tree.Import)(path, imports, features, (dir[1] === 'once'), index, env.rootpath);
+                    }
+                }
+                
+                restore();
+            },
+
+            mediaFeature: function () {
+                var e, p, nodes = [];
+
+                do {
+                    if (e = $(this.entities.keyword)) {
+                        nodes.push(e);
+                    } else if ($('(')) {
+                        p = $(this.property);
+                        e = $(this.entity);
+                        if ($(')')) {
+                            if (p && e) {
+                                nodes.push(new(tree.Paren)(new(tree.Rule)(p, e, null, i, 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 e, features = [];
+
+                do {
+                  if (e = $(this.mediaFeature)) {
+                      features.push(e);
+                      if (! $(',')) { break }
+                  } else if (e = $(this.entities.variable)) {
+                      features.push(e);
+                      if (! $(',')) { break }
+                  }
+                } while (e);
+
+                return features.length > 0 ? features : null;
+            },
+
+            media: function () {
+                var features, rules, media, debugInfo;
+
+                if (env.dumpLineNumbers)
+                    debugInfo = getDebugInfo(i, input, env);
+
+                if ($(/^@media/)) {
+                    features = $(this.mediaFeatures);
+
+                    if (rules = $(this.block)) {
+                        media = new(tree.Media)(rules, features);
+                        if(env.dumpLineNumbers)
+                            media.debugInfo = debugInfo;
+                        return media;
+                    }
                 }
             },
 
@@ -965,26 +1273,81 @@ less.Parser = function Parser(env) {
             //     @charset "utf-8";
             //
             directive: function () {
-                var name, value, rules, types;
+                var name, value, rules, identifier, e, nodes, nonVendorSpecificName,
+                    hasBlock, hasIdentifier, hasExpression;
 
                 if (input.charAt(i) !== '@') return;
 
-                if (value = $(this['import'])) {
+                if (value = $(this['import']) || $(this.media)) {
                     return value;
-                } else if (name = $(/^@media|@page/) || $(/^@(?:-webkit-|-moz-)?keyframes/)) {
-                    types = ($(/^[^{]+/) || '').trim();
+                }
+                
+                save();
+
+                name = $(/^@[a-z-]+/);
+                
+                if (!name) return;
+
+                nonVendorSpecificName = name;
+                if (name.charAt(1) == '-' && name.indexOf('-', 2) > 0) {
+                    nonVendorSpecificName = "@" + name.slice(name.indexOf('-', 2) + 1);
+                }
+
+                switch(nonVendorSpecificName) {
+                    case "@font-face":
+                        hasBlock = true;
+                        break;
+                    case "@viewport":
+                    case "@top-left":
+                    case "@top-left-corner":
+                    case "@top-center":
+                    case "@top-right":
+                    case "@top-right-corner":
+                    case "@bottom-left":
+                    case "@bottom-left-corner":
+                    case "@bottom-center":
+                    case "@bottom-right":
+                    case "@bottom-right-corner":
+                    case "@left-top":
+                    case "@left-middle":
+                    case "@left-bottom":
+                    case "@right-top":
+                    case "@right-middle":
+                    case "@right-bottom":
+                        hasBlock = true;
+                        break;
+                    case "@page":
+                    case "@document":
+                    case "@supports":
+                    case "@keyframes":
+                        hasBlock = true;
+                        hasIdentifier = true;
+                        break;
+                    case "@namespace":
+                        hasExpression = true;
+                        break;
+                }
+
+                if (hasIdentifier) {
+                    name += " " + ($(/^[^{]+/) || '').trim();
+                }
+
+                if (hasBlock)
+                {
                     if (rules = $(this.block)) {
-                        return new(tree.Directive)(name + " " + types, rules);
+                        return new(tree.Directive)(name, rules);
                     }
-                } else if (name = $(/^@[-a-z]+/)) {
-                    if (name === '@font-face') {
-                        if (rules = $(this.block)) {
-                            return new(tree.Directive)(name, rules);
+                } else {
+                    if ((value = hasExpression ? $(this.expression) : $(this.entity)) && $(';')) {
+                        var directive = new(tree.Directive)(name, value);
+                        if (env.dumpLineNumbers) {
+                            directive.debugInfo = getDebugInfo(i, input, env);
                         }
-                    } else if ((value = $(this.entity)) && $(';')) {
-                        return new(tree.Directive)(name, value);
+                        return directive;
                     }
                 }
+                
+                restore();
             },
             font: function () {
                 var value = [], expression = [], weight, shorthand, font, e;
@@ -1038,7 +1401,7 @@ less.Parser = function Parser(env) {
             multiplication: function () {
                 var m, a, op, operation;
                 if (m = $(this.operand)) {
-                    while ((op = ($('/') || $('*'))) && (a = $(this.operand))) {
+                    while (!peek(/^\/[*\/]/) && (op = ($('/') || $('*'))) && (a = $(this.operand))) {
                         operation = new(tree.Operation)(op, [operation || m, a]);
                     }
                     return operation || m;
@@ -1047,13 +1410,42 @@ less.Parser = function Parser(env) {
             addition: function () {
                 var m, a, op, operation;
                 if (m = $(this.multiplication)) {
-                    while ((op = $(/^[-+]\s+/) || (input.charAt(i - 1) != ' ' && ($('+') || $('-')))) &&
+                    while ((op = $(/^[-+]\s+/) || (!isWhitespace(input.charAt(i - 1)) && ($('+') || $('-')))) &&
                            (a = $(this.multiplication))) {
                         operation = new(tree.Operation)(op, [operation || m, a]);
                     }
                     return operation || m;
                 }
             },
+            conditions: function () {
+                var a, b, index = i, condition;
+
+                if (a = $(this.condition)) {
+                    while ($(',') && (b = $(this.condition))) {
+                        condition = new(tree.Condition)('or', condition || a, b, index);
+                    }
+                    return condition || a;
+                }
+            },
+            condition: function () {
+                var a, b, c, op, index = i, negate = false;
+
+                if ($(/^not/)) { negate = true }
+                expect('(');
+                if (a = $(this.addition) || $(this.entities.keyword) || $(this.entities.quoted)) {
+                    if (op = $(/^(?:>=|=<|[<=>])/)) {
+                        if (b = $(this.addition) || $(this.entities.keyword) || $(this.entities.quoted)) {
+                            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);
+                    }
+                    expect(')');
+                    return $(/^and/) ? new(tree.Condition)('and', c, $(this.condition)) : c;
+                }
+            },
 
             //
             // An operand is anything that can be part of an operation,
@@ -1090,7 +1482,7 @@ less.Parser = function Parser(env) {
             property: function () {
                 var name;
 
-                if (name = $(/^(\*?-?[-a-z_0-9]+)\s*:/)) {
+                if (name = $(/^(\*?-?[_a-z0-9-]+)\s*:/)) {
                     return name[1];
                 }
             }
@@ -1103,13 +1495,28 @@ if (less.mode === 'browser' || less.mode === 'rhino') {
     // Used by `@import` directives
     //
     less.Parser.importer = function (path, paths, callback, env) {
-        if (path.charAt(0) !== '/' && paths.length > 0) {
+        if (!/^([a-z-]+:)?\//.test(path) && paths.length > 0) {
             path = paths[0] + path;
         }
         // We pass `true` as 3rd argument, to force the reload of the import.
         // This is so we can get the syntax tree as opposed to just the CSS output,
         // as we need this to evaluate the current stylesheet.
-        loadStyleSheet({ href: path, title: path, type: env.mime }, callback, true);
+        loadStyleSheet({ 
+            href: path, 
+            title: path, 
+            type: env.mime, 
+            contents: env.contents, 
+            files: env.files, 
+            rootpath: env.rootpath,
+            entryPath: env.entryPath,
+            relativeUrls: env.relativeUrls }, 
+        function (e, root, data, sheet, _, path) {
+            if (e && typeof(env.errback) === "function") {
+                env.errback.call(null, path, paths, callback, env);
+            } else {
+                callback.call(null, e, root, path);
+            }
+        }, true);
     };
 }
 
diff --git a/build-tools/lib/less/rhino.js b/build-tools/lib/less/rhino.js
index ab1c886..57d60f5 100644
--- a/build-tools/lib/less/rhino.js
+++ b/build-tools/lib/less/rhino.js
@@ -1,18 +1,27 @@
 var name;
 
 function loadStyleSheet(sheet, callback, reload, remaining) {
-    var sheetName = name.slice(0, name.lastIndexOf('/') + 1) + sheet.href;
-    var input = readFile(sheetName);
-    var parser = new less.Parser();
+    var endOfPath = Math.max(name.lastIndexOf('/'), name.lastIndexOf('\\')),
+        sheetName = name.slice(0, endOfPath + 1) + sheet.href,
+        contents = sheet.contents || {},
+        input = readFile(sheetName);
+        
+    contents[sheetName] = input;
+        
+    var parser = new less.Parser({
+        paths: [sheet.href.replace(/[\w\.-]+$/, '')],
+        contents: contents
+    });
     parser.parse(input, function (e, root) {
         if (e) {
-            print("Error: " + e);
-            quit(1);
+            return error(e, sheetName);
+        }
+        try {
+            callback(e, root, input, sheet, { local: false, lastModified: 0, remaining: remaining }, sheetName);
+        } catch(e) {
+            error(e, sheetName);
         }
-        callback(root, sheet, { local: false, lastModified: 0, remaining: remaining });
     });
-
-    // callback({}, sheet, { local: true, remaining: remaining });
 }
 
 function writeFile(filename, content) {
@@ -24,8 +33,26 @@ function writeFile(filename, content) {
 
 // Command line integration via Rhino
 (function (args) {
-    name = args[0];
-    var output = args[1];
+    var output,
+        compress = false,
+        i;
+        
+    for(i = 0; i < args.length; i++) {
+        switch(args[i]) {
+            case "-x":
+                compress = true;
+                break;
+            default:
+                if (!name) {
+                    name = args[i];
+                } else if (!output) {
+                    output = args[i];
+                } else {
+                    print("unrecognised parameters");
+                    print("input_file [output_file] [-x]");
+                }
+        }
+    }
 
     if (!name) {
         print('No files present in the fileset; Check your pattern match in build.xml');
@@ -41,20 +68,56 @@ function writeFile(filename, content) {
     }
 
     var result;
-    var parser = new less.Parser();
-    parser.parse(input, function (e, root) {
-        if (e) {
-            quit(1);
-        } else {
-            result = root.toCSS();
-            if (output) {
-                writeFile(output, result);
-                print("Written to " + output);
+    try {
+        var parser = new less.Parser();
+        parser.parse(input, function (e, root) {
+            if (e) {
+                error(e, name);
+                quit(1);
             } else {
-                print(result);
+                result = root.toCSS({compress: compress || false});
+                if (output) {
+                    writeFile(output, result);
+                    print("Written to " + output);
+                } else {
+                    print(result);
+                }
+                quit(0);
             }
-            quit(0);
-        }
-    });
+        });
+    }
+    catch(e) {
+        error(e, name);
+        quit(1);
+    }
     print("done");
 }(arguments));
+
+function error(e, filename) {
+
+    var content = "Error : " + filename + "\n";
+    
+    filename = e.filename || filename;
+    
+    if (e.message) {
+        content += e.message + "\n";
+    }
+
+    var errorline = function (e, i, classname) {
+        if (e.extract[i]) {
+            content += 
+                String(parseInt(e.line) + (i - 1)) + 
+                ":" + e.extract[i] + "\n";
+        }
+    };
+
+    if (e.stack) {
+        content += e.stack;
+    } else if (e.extract) {
+        content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':\n';
+        errorline(e, 0);
+        errorline(e, 1);
+        errorline(e, 2);
+    }
+   print(content);
+}
\ No newline at end of file
diff --git a/build-tools/lib/less/tree.js b/build-tools/lib/less/tree.js
index eb08aa4..134adbd 100644
--- a/build-tools/lib/less/tree.js
+++ b/build-tools/lib/less/tree.js
@@ -1,13 +1,45 @@
-require('less/tree').find = function (obj, fun) {
+(function (tree) {
+
+tree.debugInfo = function(env, ctx) {
+    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)+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, '\\$&') +
+        '}line{font-family:\\00003' + ctx.debugInfo.lineNumber + '}}\n';
+};
+
+tree.find = function (obj, fun) {
     for (var i = 0, r; i < obj.length; i++) {
         if (r = fun.call(obj, obj[i])) { return r }
     }
     return null;
 };
-require('less/tree').jsify = function (obj) {
+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);
     }
 };
+
+})(require('./tree'));
diff --git a/build-tools/lib/less/tree/alpha.js b/build-tools/lib/less/tree/alpha.js
index 551ccba..139ae92 100644
--- a/build-tools/lib/less/tree/alpha.js
+++ b/build-tools/lib/less/tree/alpha.js
@@ -14,4 +14,4 @@ tree.Alpha.prototype = {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/anonymous.js b/build-tools/lib/less/tree/anonymous.js
index 89840d0..4461490 100644
--- a/build-tools/lib/less/tree/anonymous.js
+++ b/build-tools/lib/less/tree/anonymous.js
@@ -7,7 +7,21 @@ tree.Anonymous.prototype = {
     toCSS: function () {
         return this.value;
     },
-    eval: function () { return this }
+    eval: function () { return this },
+    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('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/assignment.js b/build-tools/lib/less/tree/assignment.js
new file mode 100644
index 0000000..a5559ad
--- /dev/null
+++ b/build-tools/lib/less/tree/assignment.js
@@ -0,0 +1,19 @@
+(function (tree) {
+
+tree.Assignment = function (key, val) {
+    this.key = key;
+    this.value = val;
+};
+tree.Assignment.prototype = {
+    toCSS: function () {
+        return this.key + '=' + (this.value.toCSS ? this.value.toCSS() : this.value);
+    },
+    eval: function (env) {
+        if (this.value.eval) {
+            return new(tree.Assignment)(this.key, this.value.eval(env));
+        }
+        return this;
+    }
+};
+
+})(require('../tree'));
\ No newline at end of file
diff --git a/build-tools/lib/less/tree/call.js b/build-tools/lib/less/tree/call.js
index 4a72932..f8045ed 100644
--- a/build-tools/lib/less/tree/call.js
+++ b/build-tools/lib/less/tree/call.js
@@ -3,17 +3,19 @@
 //
 // A function call node.
 //
-tree.Call = function (name, args, index) {
+tree.Call = function (name, args, index, filename) {
     this.name = name;
     this.args = args;
     this.index = index;
+    this.filename = filename;
 };
 tree.Call.prototype = {
     //
     // When evaluating a function call,
     // we either find the function in `tree.functions` [1],
     // in which case we call it, passing the  evaluated arguments,
-    // or we simply print it out as it appeared originally [2].
+    // 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.
     //
@@ -22,19 +24,26 @@ tree.Call.prototype = {
     // The function should receive the value, not the variable.
     //
     eval: function (env) {
-        var args = this.args.map(function (a) { return a.eval(env) });
+        var args = this.args.map(function (a) { return a.eval(env) }),
+            result;
 
         if (this.name in tree.functions) { // 1.
             try {
-                return tree.functions[this.name].apply(tree.functions, args);
+                result = tree.functions[this.name].apply(tree.functions, args);
+                if (result != null) {
+                    return result;
+                }
             } catch (e) {
-                throw { message: "error evaluating function `" + this.name + "`",
-                        index: this.index };
+                throw { type: e.type || "Runtime",
+                        message: "error evaluating function `" + this.name + "`" +
+                                 (e.message ? ': ' + e.message : ''),
+                        index: this.index, filename: this.filename };
             }
-        } else { // 2.
-            return new(tree.Anonymous)(this.name +
-                   "(" + args.map(function (a) { return a.toCSS() }).join(', ') + ")");
         }
+        
+        // 2.
+        return new(tree.Anonymous)(this.name +
+            "(" + args.map(function (a) { return a.toCSS(env) }).join(', ') + ")");
     },
 
     toCSS: function (env) {
@@ -42,4 +51,4 @@ tree.Call.prototype = {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/color.js b/build-tools/lib/less/tree/color.js
index bb7646a..6adf317 100644
--- a/build-tools/lib/less/tree/color.js
+++ b/build-tools/lib/less/tree/color.js
@@ -94,8 +94,18 @@ tree.Color.prototype = {
             i = (i > 255 ? 255 : (i < 0 ? 0 : i)).toString(16);
             return i.length === 1 ? '0' + i : i;
         }).join('');
+    },
+    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;
     }
 };
 
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/comment.js b/build-tools/lib/less/tree/comment.js
index 2d95dff..f4a3384 100644
--- a/build-tools/lib/less/tree/comment.js
+++ b/build-tools/lib/less/tree/comment.js
@@ -11,4 +11,4 @@ tree.Comment.prototype = {
     eval: function () { return this }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/condition.js b/build-tools/lib/less/tree/condition.js
new file mode 100644
index 0000000..6b79dc9
--- /dev/null
+++ b/build-tools/lib/less/tree/condition.js
@@ -0,0 +1,42 @@
+(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.eval = function (env) {
+    var a = this.lvalue.eval(env),
+        b = this.rvalue.eval(env);
+
+    var i = this.index, result;
+
+    var 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 === '=<';
+                    case  0: return op === '=' || op === '>=' || op === '=<';
+                    case  1: return op === '>' || op === '>=';
+                }
+        }
+    })(this.op);
+    return this.negate ? !result : result;
+};
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/dimension.js b/build-tools/lib/less/tree/dimension.js
index 41f3ca2..22241b8 100644
--- a/build-tools/lib/less/tree/dimension.js
+++ b/build-tools/lib/less/tree/dimension.js
@@ -28,7 +28,24 @@ tree.Dimension.prototype = {
         return new(tree.Dimension)
                   (tree.operate(op, this.value, other.value),
                   this.unit || other.unit);
+    },
+
+    compare: function (other) {
+        if (other instanceof tree.Dimension) {
+            if (other.value > this.value) {
+                return -1;
+            } else if (other.value < this.value) {
+                return 1;
+            } else {
+                if (other.unit && this.unit !== other.unit) {
+                    return -1;
+                }
+                return 0;
+            }
+        } else {
+            return -1;
+        }
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/directive.js b/build-tools/lib/less/tree/directive.js
index fbe9a93..4d682e6 100644
--- a/build-tools/lib/less/tree/directive.js
+++ b/build-tools/lib/less/tree/directive.js
@@ -2,8 +2,10 @@
 
 tree.Directive = function (name, value) {
     this.name = name;
+
     if (Array.isArray(value)) {
         this.ruleset = new(tree.Ruleset)([], value);
+        this.ruleset.allowImports = true;
     } else {
         this.value = value;
     }
@@ -20,14 +22,18 @@ tree.Directive.prototype = {
         }
     },
     eval: function (env) {
-        env.frames.unshift(this);
-        this.ruleset = this.ruleset && this.ruleset.eval(env);
-        env.frames.shift();
-        return this;
+        var evaldDirective = this;
+        if (this.ruleset) {
+            env.frames.unshift(this);
+            evaldDirective = new(tree.Directive)(this.name);
+            evaldDirective.ruleset = this.ruleset.eval(env);
+            env.frames.shift();
+        }
+        return evaldDirective;
     },
     variable: function (name) { return tree.Ruleset.prototype.variable.call(this.ruleset, name) },
     find: function () { return tree.Ruleset.prototype.find.apply(this.ruleset, arguments) },
     rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.ruleset) }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/element.js b/build-tools/lib/less/tree/element.js
index 27cf822..4e251ee 100644
--- a/build-tools/lib/less/tree/element.js
+++ b/build-tools/lib/less/tree/element.js
@@ -1,19 +1,35 @@
 (function (tree) {
 
-tree.Element = function (combinator, value) {
+tree.Element = function (combinator, value, index) {
     this.combinator = combinator instanceof tree.Combinator ?
                       combinator : new(tree.Combinator)(combinator);
-    this.value = value ? value.trim() : "";
+
+    if (typeof(value) === 'string') {
+        this.value = value.trim();
+    } else if (value) {
+        this.value = value;
+    } else {
+        this.value = "";
+    }
+    this.index = index;
+};
+tree.Element.prototype.eval = function (env) {
+    return new(tree.Element)(this.combinator,
+                             this.value.eval ? this.value.eval(env) : this.value,
+                             this.index);
 };
 tree.Element.prototype.toCSS = function (env) {
-    return this.combinator.toCSS(env || {}) + this.value;
+	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.Combinator = function (value) {
     if (value === ' ') {
         this.value = ' ';
-    } else if (value === '& ') {
-        this.value = '& ';
     } else {
         this.value = value ? value.trim() : "";
     }
@@ -22,14 +38,12 @@ tree.Combinator.prototype.toCSS = function (env) {
     return {
         ''  : '',
         ' ' : ' ',
-        '&' : '',
-        '& ' : ' ',
         ':' : ' :',
-        '::': '::',
         '+' : env.compress ? '+' : ' + ',
         '~' : env.compress ? '~' : ' ~ ',
-        '>' : env.compress ? '>' : ' > '
+        '>' : env.compress ? '>' : ' > ',
+        '|' : env.compress ? '|' : ' | '
     }[this.value];
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/expression.js b/build-tools/lib/less/tree/expression.js
index f638a1b..fbfa9c5 100644
--- a/build-tools/lib/less/tree/expression.js
+++ b/build-tools/lib/less/tree/expression.js
@@ -15,9 +15,9 @@ tree.Expression.prototype = {
     },
     toCSS: function (env) {
         return this.value.map(function (e) {
-            return e.toCSS(env);
+            return e.toCSS ? e.toCSS(env) : '';
         }).join(' ');
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/import.js b/build-tools/lib/less/tree/import.js
index 427c109..02594a7 100644
--- a/build-tools/lib/less/tree/import.js
+++ b/build-tools/lib/less/tree/import.js
@@ -11,27 +11,30 @@
 // `import,push`, we also pass it a callback, which it'll call once
 // the file has been fetched, and parsed.
 //
-tree.Import = function (path, imports) {
+tree.Import = function (path, imports, features, once, index, rootpath) {
     var that = this;
 
+    this.once = once;
+    this.index = index;
     this._path = path;
-
+    this.features = features && new(tree.Value)(features);
+    this.rootpath = rootpath;
+		
     // The '.less' extension is optional
     if (path instanceof tree.Quoted) {
-        this.path = /\.(le?|c)ss(\?.*)?$/.test(path.value) ? path.value : path.value + '.less';
+        this.path = /(\.[a-z]*$)|([\?;].*)$/.test(path.value) ? path.value : path.value + '.less';
     } else {
         this.path = path.value.value || path.value;
     }
 
-    this.css = /css(\?.*)?$/.test(this.path);
+    this.css = /css([\?;].*)?$/.test(this.path);
 
     // Only pre-compile .less files
     if (! this.css) {
-        imports.push(this.path, function (root) {
-            if (! root) {
-                throw new(Error)("Error parsing " + that.path);
-            }
-            that.root = root;
+        imports.push(this.path, function (e, root, imported) {
+            if (e) { e.index = index }
+            if (imported && that.once) that.skip = imported;
+            that.root = root || new(tree.Ruleset)([], []);
         });
     }
 };
@@ -46,32 +49,34 @@ tree.Import = function (path, imports) {
 // ruleset.
 //
 tree.Import.prototype = {
-    toCSS: function () {
+    toCSS: function (env) {
+        var features = this.features ? ' ' + this.features.toCSS(env) : '';
+
         if (this.css) {
-            return "@import " + this._path.toCSS() + ';\n';
+            // Add the base path if the import is relative
+            if (typeof this._path.value === "string" && !/^(?:[a-z-]+:|\/)/.test(this._path.value)) {
+                this._path.value = this.rootpath + this._path.value;
+            }
+            return "@import " + this._path.toCSS() + features + ';\n';
         } else {
             return "";
         }
     },
     eval: function (env) {
-        var ruleset;
+        var ruleset, features = this.features && this.features.eval(env);
+
+        if (this.skip) return [];
 
         if (this.css) {
             return this;
         } else {
-            ruleset = new(tree.Ruleset)(null, this.root.rules.slice(0));
+            ruleset = new(tree.Ruleset)([], this.root.rules.slice(0));
 
-            for (var i = 0; i < ruleset.rules.length; i++) {
-                if (ruleset.rules[i] instanceof tree.Import) {
-                    Array.prototype
-                         .splice
-                         .apply(ruleset.rules,
-                                [i, 1].concat(ruleset.rules[i].eval(env)));
-                }
-            }
-            return ruleset.rules;
+            ruleset.evalImports(env);
+
+            return this.features ? new(tree.Media)(ruleset.rules, this.features.value) : ruleset.rules;
         }
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/javascript.js b/build-tools/lib/less/tree/javascript.js
index 4ec66b9..772a31d 100644
--- a/build-tools/lib/less/tree/javascript.js
+++ b/build-tools/lib/less/tree/javascript.js
@@ -47,5 +47,5 @@ tree.JavaScript.prototype = {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
 
diff --git a/build-tools/lib/less/tree/keyword.js b/build-tools/lib/less/tree/keyword.js
index a4431ba..701b79e 100644
--- a/build-tools/lib/less/tree/keyword.js
+++ b/build-tools/lib/less/tree/keyword.js
@@ -3,7 +3,17 @@
 tree.Keyword = function (value) { this.value = value };
 tree.Keyword.prototype = {
     eval: function () { return this },
-    toCSS: function () { return this.value }
+    toCSS: function () { return this.value },
+    compare: function (other) {
+        if (other instanceof tree.Keyword) {
+            return other.value === this.value ? 0 : 1;
+        } else {
+            return -1;
+        }
+    }
 };
 
-})(require('less/tree'));
+tree.True = new(tree.Keyword)('true');
+tree.False = new(tree.Keyword)('false');
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/media.js b/build-tools/lib/less/tree/media.js
new file mode 100644
index 0000000..d2a5347
--- /dev/null
+++ b/build-tools/lib/less/tree/media.js
@@ -0,0 +1,121 @@
+(function (tree) {
+
+tree.Media = function (value, features) {
+    var selectors = this.emptySelectors();
+
+    this.features = new(tree.Value)(features);
+    this.ruleset = new(tree.Ruleset)(selectors, value);
+    this.ruleset.allowImports = true;
+};
+tree.Media.prototype = {
+    toCSS: function (ctx, env) {
+        var features = this.features.toCSS(env);
+
+        this.ruleset.root = (ctx.length === 0 || ctx[0].multiMedia);
+        return '@media ' + features + (env.compress ? '{' : ' {\n  ') +
+               this.ruleset.toCSS(ctx, env).trim().replace(/\n/g, '\n  ') +
+                           (env.compress ? '}': '\n}\n');
+    },
+    eval: function (env) {
+        if (!env.mediaBlocks) {
+            env.mediaBlocks = [];
+            env.mediaPath = [];
+        }
+        
+        var media = new(tree.Media)([], []);
+        if(this.debugInfo) {
+            this.ruleset.debugInfo = this.debugInfo;
+            media.debugInfo = this.debugInfo;
+        }
+        media.features = this.features.eval(env);
+        
+        env.mediaPath.push(media);
+        env.mediaBlocks.push(media);
+        
+        env.frames.unshift(this.ruleset);
+        media.ruleset = this.ruleset.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.ruleset, name) },
+    find: function () { return tree.Ruleset.prototype.find.apply(this.ruleset, arguments) },
+    rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.ruleset) },
+    emptySelectors: function() { 
+        var el = new(tree.Element)('', '&', 0);
+        return [new(tree.Selector)([el])];
+    },
+
+    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.ruleset = new(tree.Ruleset)(selectors.slice(0), [this.ruleset]);
+    }
+};
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/mixin.js b/build-tools/lib/less/tree/mixin.js
index 24cb8e4..0533036 100644
--- a/build-tools/lib/less/tree/mixin.js
+++ b/build-tools/lib/less/tree/mixin.js
@@ -1,50 +1,84 @@
 (function (tree) {
 
 tree.mixin = {};
-tree.mixin.Call = function (elements, args, index) {
+tree.mixin.Call = function (elements, args, index, filename, important) {
     this.selector = new(tree.Selector)(elements);
     this.arguments = args;
     this.index = index;
+    this.filename = filename;
+    this.important = important;
 };
 tree.mixin.Call.prototype = {
     eval: function (env) {
-        var mixins, args, rules = [], match = false;
+        var mixins, mixin, args, rules = [], match = false, i, m, f, isRecursive, isOneFound;
 
-        for (var i = 0; i < env.frames.length; i++) {
+        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) {
-                args = this.arguments && this.arguments.map(function (a) { return a.eval(env) });
-                for (var m = 0; m < mixins.length; m++) {
-                    if (mixins[m].match(args, env)) {
-                        try {
-                            Array.prototype.push.apply(
-                                  rules, mixins[m].eval(env, this.arguments).rules);
-                            match = true;
-                        } catch (e) {
-                            throw { message: e.message, index: e.index, stack: e.stack, call: this.index };
+                isOneFound = true;
+                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)) {
+                        if (!mixin.matchCondition || mixin.matchCondition(args, env)) {
+                            try {
+                                Array.prototype.push.apply(
+                                      rules, mixin.eval(env, args, this.important).rules);
+                            } catch (e) {
+                                throw { message: e.message, index: this.index, filename: this.filename, stack: e.stack };
+                            }
+                        }
+                        match = true;
+                    }
                 }
                 if (match) {
                     return rules;
-                } else {
-                    throw { message: 'No matching definition was found for `' +
-                                      this.selector.toCSS().trim() + '('      +
-                                      this.arguments.map(function (a) {
-                                          return a.toCSS();
-                                      }).join(', ') + ")`",
-                            index:   this.index };
                 }
             }
         }
-        throw { message: this.selector.toCSS().trim() + " is undefined",
-                index: this.index };
+        if (isOneFound) {
+            throw { type:    'Runtime',
+                    message: 'No matching definition was found for `' +
+                              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(', ') : "") + ")`",
+                    index:   this.index, filename: this.filename };
+        } else {
+            throw { type: 'Name',
+                message: this.selector.toCSS().trim() + " is undefined",
+                index: this.index, filename: this.filename };
+        }
     }
 };
 
-tree.mixin.Definition = function (name, params, rules) {
+tree.mixin.Definition = function (name, params, rules, condition, variadic) {
     this.name = name;
     this.selectors = [new(tree.Selector)([new(tree.Element)(null, name)])];
     this.params = params;
+    this.condition = condition;
+    this.variadic = variadic;
     this.arity = params.length;
     this.rules = rules;
     this._lookups = {};
@@ -62,39 +96,111 @@ tree.mixin.Definition.prototype = {
     find:      function ()     { return this.parent.find.apply(this, arguments) },
     rulesets:  function ()     { return this.parent.rulesets.apply(this) },
 
-    eval: function (env, args) {
-        var frame = new(tree.Ruleset)(null, []), context, _arguments = [];
+    evalParams: function (env, mixinEnv, args, evaldArguments) {
+        var frame = new(tree.Ruleset)(null, []), varargs, arg, params = this.params.slice(0), i, j, val, name, isNamedFound, argIndex;
+        
+        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.rules.unshift(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];
 
-        for (var i = 0, val; i < this.params.length; i++) {
-            if (this.params[i].name) {
-                if (val = (args && args[i]) || this.params[i].value) {
-                    frame.rules.unshift(new(tree.Rule)(this.params[i].name, val.eval(env)));
+            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.rules.unshift(new(tree.Rule)(name, new(tree.Expression)(varargs).eval(env)));
                 } else {
-                    throw { message: "wrong number of arguments for " + this.name +
+                    val = arg && arg.value;
+                    if (val) {
+                        val = val.eval(env);
+                    } else if (params[i].value) {
+                        val = params[i].value.eval(mixinEnv);
+                    } else {
+                        throw { type: 'Runtime', message: "wrong number of arguments for " + this.name +
                             ' (' + args.length + ' for ' + this.arity + ')' };
+                    }
+                    
+                    frame.rules.unshift(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++;
         }
-        for (var i = 0; i < Math.max(this.params.length, args && args.length); i++) {
-            _arguments.push(args[i] || this.params[i].value);
-        }
+
+        return frame;
+    },
+    eval: function (env, args, important) {
+        var _arguments = [],
+            mixinFrames = this.frames.concat(env.frames),
+            frame = this.evalParams(env, {frames: mixinFrames}, args, _arguments), 
+            context, rules, start, ruleset;
+
         frame.rules.unshift(new(tree.Rule)('@arguments', new(tree.Expression)(_arguments).eval(env)));
 
-        return new(tree.Ruleset)(null, this.rules.slice(0)).eval({
-            frames: [this, frame].concat(this.frames, env.frames)
+        rules = important ?
+            this.parent.makeImportant.apply(this).rules : this.rules.slice(0);
+
+        ruleset = new(tree.Ruleset)(null, rules).eval({
+            frames: [this, frame].concat(mixinFrames)
         });
+        ruleset.originalRuleset = this;
+        return ruleset;
     },
-    match: function (args, env) {
-        var argsLength = (args && args.length) || 0, len;
+    matchCondition: function (args, env) {
+        if (this.condition && !this.condition.eval({
+            frames: [this.evalParams(env, {frames: this.frames.concat(env.frames)}, args, [])].concat(env.frames)
+        }))                                                           { return false }
+        return true;
+    },
+    matchArgs: function (args, env) {
+        var argsLength = (args && args.length) || 0, len, frame;
 
-        if (argsLength < this.required)                               { return false }
-        if ((this.required > 0) && (argsLength > this.params.length)) { return false }
+        if (! this.variadic) {
+            if (argsLength < this.required)                               { return false }
+            if (argsLength > this.params.length)                          { return false }
+            if ((this.required > 0) && (argsLength > this.params.length)) { return false }
+        }
 
         len = Math.min(argsLength, this.arity);
 
         for (var i = 0; i < len; i++) {
-            if (!this.params[i].name) {
-                if (args[i].eval(env).toCSS() != this.params[i].value.eval(env).toCSS()) {
+            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;
                 }
             }
@@ -103,4 +209,4 @@ tree.mixin.Definition.prototype = {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/operation.js b/build-tools/lib/less/tree/operation.js
index d2e4d57..3c4f093 100644
--- a/build-tools/lib/less/tree/operation.js
+++ b/build-tools/lib/less/tree/operation.js
@@ -17,6 +17,11 @@ tree.Operation.prototype.eval = function (env) {
                     message: "Can't substract or divide a color from a number" };
         }
     }
+    if (!a.operate) {
+        throw { name: "OperationError",
+                message: "Operation on an invalid type" };
+    }
+
     return a.operate(this.op, b);
 };
 
@@ -29,4 +34,4 @@ tree.operate = function (op, a, b) {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/paren.js b/build-tools/lib/less/tree/paren.js
new file mode 100644
index 0000000..384a43c
--- /dev/null
+++ b/build-tools/lib/less/tree/paren.js
@@ -0,0 +1,16 @@
+
+(function (tree) {
+
+tree.Paren = function (node) {
+    this.value = node;
+};
+tree.Paren.prototype = {
+    toCSS: function (env) {
+        return '(' + this.value.toCSS(env) + ')';
+    },
+    eval: function (env) {
+        return new(tree.Paren)(this.value.eval(env));
+    }
+};
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/quoted.js b/build-tools/lib/less/tree/quoted.js
index 6ddfa40..4ec6713 100644
--- a/build-tools/lib/less/tree/quoted.js
+++ b/build-tools/lib/less/tree/quoted.js
@@ -20,10 +20,24 @@ tree.Quoted.prototype = {
             return new(tree.JavaScript)(exp, that.index, true).eval(env).value;
         }).replace(/@\{([\w-]+)\}/g, function (_, name) {
             var v = new(tree.Variable)('@' + name, that.index).eval(env);
-            return v.value || v.toCSS();
+            return (v instanceof tree.Quoted) ? v.value : v.toCSS();
         });
         return new(tree.Quoted)(this.quote + value + this.quote, value, this.escaped, this.index);
+    },
+    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('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/ratio.js b/build-tools/lib/less/tree/ratio.js
new file mode 100644
index 0000000..f7622fb
--- /dev/null
+++ b/build-tools/lib/less/tree/ratio.js
@@ -0,0 +1,13 @@
+(function (tree) {
+
+tree.Ratio = function (value) {
+    this.value = value;
+};
+tree.Ratio.prototype = {
+    toCSS: function (env) {
+        return this.value;
+    },
+    eval: function () { return this }
+};
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/rule.js b/build-tools/lib/less/tree/rule.js
index 18cc49b..8990fef 100644
--- a/build-tools/lib/less/tree/rule.js
+++ b/build-tools/lib/less/tree/rule.js
@@ -1,10 +1,11 @@
 (function (tree) {
 
-tree.Rule = function (name, value, important, index) {
+tree.Rule = function (name, value, important, index, inline) {
     this.name = name;
     this.value = (value instanceof tree.Value) ? value : new(tree.Value)([value]);
     this.important = important ? ' ' + important.trim() : '';
     this.index = index;
+    this.inline = inline || false;
 
     if (name.charAt(0) === '@') {
         this.variable = true;
@@ -15,12 +16,22 @@ tree.Rule.prototype.toCSS = function (env) {
     else {
         return this.name + (env.compress ? ':' : ': ') +
                this.value.toCSS(env) +
-               this.important + ";";
+               this.important + (this.inline ? "" : ";");
     }
 };
 
 tree.Rule.prototype.eval = function (context) {
-    return new(tree.Rule)(this.name, this.value.eval(context), this.important, this.index);
+    return new(tree.Rule)(this.name,
+                          this.value.eval(context),
+                          this.important,
+                          this.index, this.inline);
+};
+
+tree.Rule.prototype.makeImportant = function () {
+    return new(tree.Rule)(this.name,
+                          this.value,
+                          "!important",
+                          this.index, this.inline);
 };
 
 tree.Shorthand = function (a, b) {
@@ -35,4 +46,4 @@ tree.Shorthand.prototype = {
     eval: function () { return this }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/ruleset.js b/build-tools/lib/less/tree/ruleset.js
index cc9a60a..a198617 100644
--- a/build-tools/lib/less/tree/ruleset.js
+++ b/build-tools/lib/less/tree/ruleset.js
@@ -1,27 +1,31 @@
 (function (tree) {
 
-tree.Ruleset = function (selectors, rules) {
+tree.Ruleset = function (selectors, rules, strictImports) {
     this.selectors = selectors;
     this.rules = rules;
     this._lookups = {};
+    this.strictImports = strictImports;
 };
 tree.Ruleset.prototype = {
     eval: function (env) {
-        var ruleset = new(tree.Ruleset)(this.selectors, this.rules.slice(0));
-
+        var selectors = this.selectors && this.selectors.map(function (s) { return s.eval(env) });
+        var ruleset = new(tree.Ruleset)(selectors, this.rules.slice(0), this.strictImports);
+        var rules;
+        
+        ruleset.originalRuleset = this;
         ruleset.root = this.root;
+        ruleset.allowImports = this.allowImports;
+
+        if(this.debugInfo) {
+            ruleset.debugInfo = this.debugInfo;
+        }
 
         // push the current ruleset to the frames stack
         env.frames.unshift(ruleset);
 
         // Evaluate imports
-        if (ruleset.root) {
-            for (var i = 0; i < ruleset.rules.length; i++) {
-                if (ruleset.rules[i] instanceof tree.Import) {
-                    Array.prototype.splice
-                         .apply(ruleset.rules, [i, 1].concat(ruleset.rules[i].eval(env)));
-                }
-            }
+        if (ruleset.root || ruleset.allowImports || !ruleset.strictImports) {
+            ruleset.evalImports(env);
         }
 
         // Store the frames around mixin definitions,
@@ -31,12 +35,16 @@ tree.Ruleset.prototype = {
                 ruleset.rules[i].frames = env.frames.slice(0);
             }
         }
+        
+        var mediaBlockCount = (env.mediaBlocks && env.mediaBlocks.length) || 0;
 
         // Evaluate mixin calls.
         for (var i = 0; i < ruleset.rules.length; i++) {
             if (ruleset.rules[i] instanceof tree.mixin.Call) {
-                Array.prototype.splice
-                     .apply(ruleset.rules, [i, 1].concat(ruleset.rules[i].eval(env)));
+                rules = ruleset.rules[i].eval(env);
+                ruleset.rules.splice.apply(ruleset.rules, [i, 1].concat(rules));
+                i += rules.length-1;
+                ruleset.resetCache();
             }
         }
 
@@ -51,12 +59,47 @@ tree.Ruleset.prototype = {
 
         // Pop the stack
         env.frames.shift();
+        
+        if (env.mediaBlocks) {
+            for(var i = mediaBlockCount; i < env.mediaBlocks.length; i++) {
+                env.mediaBlocks[i].bubbleSelectors(selectors);
+            }
+        }
 
         return ruleset;
     },
-    match: function (args) {
+    evalImports: function(env) {
+        var i, rules;
+        for (i = 0; i < this.rules.length; i++) {
+            if (this.rules[i] instanceof tree.Import) {
+                rules = this.rules[i].eval(env);
+                if (typeof rules.length === "number") {
+                    this.rules.splice.apply(this.rules, [i, 1].concat(rules));
+                    i+= rules.length-1;
+                } else {
+                    this.rules.splice(i, 1, rules);
+                }
+                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;
     },
+    resetCache: function () {
+        this._rulesets = null;
+        this._variables = null;
+        this._lookups = {};
+    },
     variables: function () {
         if (this._variables) { return this._variables }
         else {
@@ -111,25 +154,41 @@ tree.Ruleset.prototype = {
     toCSS: function (context, env) {
         var css = [],      // The CSS output
             rules = [],    // node.Rule instances
+           _rules = [],    //
             rulesets = [], // node.Ruleset instances
             paths = [],    // Current selectors
             selector,      // The fully rendered selector
+            debugInfo,     // Line number debugging
             rule;
 
         if (! this.root) {
-            if (context.length === 0) {
-                paths = this.selectors.map(function (s) { return [s] });
-            } else {
-                this.joinSelectors( paths, context, this.selectors );
-            }
+            this.joinSelectors(paths, context, this.selectors);
         }
 
         // Compile rules and rulesets
         for (var i = 0; i < this.rules.length; i++) {
             rule = this.rules[i];
 
-            if (rule.rules || (rule instanceof tree.Directive)) {
+            if (rule.rules || (rule instanceof tree.Media)) {
                 rulesets.push(rule.toCSS(paths, env));
+            } else if (rule instanceof tree.Directive) {
+                var cssValue = rule.toCSS(paths, env);
+                // Output only the first @charset definition as such - convert the others
+                // to comments in case debug is enabled
+                if (rule.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 (env.charset) {
+                        if (rule.debugInfo) {
+                            rulesets.push(tree.debugInfo(env, rule));
+                            rulesets.push(new tree.Comment("/* "+cssValue.replace(/\n/g, "")+" */\n").toCSS(env));
+                        }
+                        continue;
+                    }
+                    env.charset = true;
+                }
+                rulesets.push(cssValue);
             } else if (rule instanceof tree.Comment) {
                 if (!rule.silent) {
                     if (this.root) {
@@ -156,12 +215,22 @@ tree.Ruleset.prototype = {
             css.push(rules.join(env.compress ? '' : '\n'));
         } else {
             if (rules.length > 0) {
+                debugInfo = tree.debugInfo(env, this);
                 selector = paths.map(function (p) {
                     return p.map(function (s) {
                         return s.toCSS(env);
                     }).join('').trim();
-                }).join(env.compress ? ',' : (paths.length > 3 ? ',\n' : ', '));
-                css.push(selector,
+                }).join(env.compress ? ',' : ',\n');
+
+                // Remove duplicates
+                for (var i = rules.length - 1; i >= 0; i--) {
+                    if (_rules.indexOf(rules[i]) === -1) {
+                        _rules.unshift(rules[i]);
+                    }
+                }
+                rules = _rules;
+
+                css.push(debugInfo + selector + 
                         (env.compress ? '{' : ' {\n  ') +
                         rules.join(env.compress ? '' : '\n  ') +
                         (env.compress ? '}' : '\n}\n'));
@@ -169,7 +238,7 @@ tree.Ruleset.prototype = {
         }
         css.push(rulesets);
 
-        return css.join('') + (env.compress ? '\n' : '');
+        return css.join('')  + (env.compress ? '\n' : '');
     },
 
     joinSelectors: function (paths, context, selectors) {
@@ -179,34 +248,167 @@ tree.Ruleset.prototype = {
     },
 
     joinSelector: function (paths, context, selector) {
-        var before = [], after = [], beforeElements = [],
-            afterElements = [], hasParentSelector = false, el;
 
-        for (var i = 0; i < selector.elements.length; i++) {
+        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.combinator.value[0] === '&') {
+            if (el.value === '&') {
                 hasParentSelector = true;
             }
-            if (hasParentSelector) afterElements.push(el);
-            else                   beforeElements.push(el);
+        }
+    
+        if (!hasParentSelector) {
+            if (context.length > 0) {
+                for(i = 0; i < context.length; i++) {
+                    paths.push(context[i].concat(selector));
+                }
+            }
+            else {
+                paths.push([selector]);
+            }
+            return;
         }
 
-        if (! hasParentSelector) {
-            afterElements = beforeElements;
-            beforeElements = [];
+        // 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)); //new Element(el.Combinator,  ""));
+                        }
+                        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 = new(tree.Selector)(lastSelector.elements.slice(0));
+                                newJoinedSelectorEmpty = false;
+                            }
+                            else {
+                                newJoinedSelector = new(tree.Selector)([]);
+                            }
+
+                            //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, 0));
+                                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);
         }
 
-        if (beforeElements.length > 0) {
-            before.push(new(tree.Selector)(beforeElements));
+        for(i = 0; i < newSelectors.length; i++) {
+            paths.push(newSelectors[i]);
         }
+    },
+    
+    mergeElementsOnToSelectors: function(elements, selectors) {
+        var i, sel;
 
-        if (afterElements.length > 0) {
-            after.push(new(tree.Selector)(afterElements));
+        if (selectors.length == 0) {
+            selectors.push([ new(tree.Selector)(elements) ]);
+            return;
         }
 
-        for (var c = 0; c < context.length; c++) {
-            paths.push(before.concat(context[c]).concat(after));
+        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] = new(tree.Selector)(sel[sel.length - 1].elements.concat(elements));
+            }
+            else {
+                sel.push(new(tree.Selector)(elements));
+            }
         }
     }
 };
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/selector.js b/build-tools/lib/less/tree/selector.js
index ddc6842..1ce2c30 100644
--- a/build-tools/lib/less/tree/selector.js
+++ b/build-tools/lib/less/tree/selector.js
@@ -2,41 +2,51 @@
 
 tree.Selector = function (elements) {
     this.elements = elements;
-    if (this.elements[0].combinator.value === "") {
-        this.elements[0].combinator.value = ' ';
-    }
 };
 tree.Selector.prototype.match = function (other) {
-    var value = this.elements[0].value,
-        len   = this.elements.length,
-        olen  = other.elements.length;
+    var elements = this.elements,
+        len = elements.length,
+        oelements, olen, max, i;
 
-    if (len > olen) {
-        return value === other.elements[0].value;
-    }
+    oelements = other.elements.slice(
+        (other.elements.length && other.elements[0].value === "&") ? 1 : 0);
+    olen = oelements.length;
+    max = Math.min(len, olen)
 
-    for (var i = 0; i < olen; i ++) {
-        if (value === other.elements[i].value) {
-            for (var j = 1; j < len; j ++) {
-                if (this.elements[j].value !== other.elements[i + j].value) {
-                    return false;
-                }
+    if (olen === 0 || len < olen) {
+        return false;
+    } else {
+        for (i = 0; i < max; i++) {
+            if (elements[i].value !== oelements[i].value) {
+                return false;
             }
-            return true;
         }
     }
-    return false;
+    return true;
+};
+tree.Selector.prototype.eval = function (env) {
+    return new(tree.Selector)(this.elements.map(function (e) {
+        return e.eval(env);
+    }));
 };
 tree.Selector.prototype.toCSS = function (env) {
     if (this._css) { return this._css }
-
-    return this._css = this.elements.map(function (e) {
+    
+    if (this.elements[0].combinator.value === "") {
+        this._css = ' ';
+    } else {
+        this._css = '';
+    }
+    
+    this._css += this.elements.map(function (e) {
         if (typeof(e) === 'string') {
             return ' ' + e.trim();
         } else {
             return e.toCSS(env);
         }
     }).join('');
+    
+    return this._css;
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/unicode-descriptor.js b/build-tools/lib/less/tree/unicode-descriptor.js
new file mode 100644
index 0000000..79b6b23
--- /dev/null
+++ b/build-tools/lib/less/tree/unicode-descriptor.js
@@ -0,0 +1,13 @@
+(function (tree) {
+
+tree.UnicodeDescriptor = function (value) {
+    this.value = value;
+};
+tree.UnicodeDescriptor.prototype = {
+    toCSS: function (env) {
+        return this.value;
+    },
+    eval: function () { return this }
+};
+
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/url.js b/build-tools/lib/less/tree/url.js
index f427070..e37dbef 100644
--- a/build-tools/lib/less/tree/url.js
+++ b/build-tools/lib/less/tree/url.js
@@ -1,25 +1,27 @@
 (function (tree) {
 
-tree.URL = function (val, paths) {
-    if (val.data) {
-        this.attrs = val;
-    } else {
-        // Add the base path if the URL is relative and we are in the browser
-        if (!/^(?:https?:\/|file:\/|data:\/)?\//.test(val.value) && paths.length > 0 && typeof(window) !== 'undefined') {
-            val.value = paths[0] + (val.value.charAt(0) === '/' ? val.value.slice(1) : val.value);
-        }
-        this.value = val;
-        this.paths = paths;
-    }
+tree.URL = function (val, rootpath) {
+    this.value = val;
+    this.rootpath = rootpath;
 };
 tree.URL.prototype = {
     toCSS: function () {
-        return "url(" + (this.attrs ? 'data:' + this.attrs.mime + this.attrs.charset + this.attrs.base64 + this.attrs.data
-                                    : this.value.toCSS()) + ")";
+        return "url(" + this.value.toCSS() + ")";
     },
     eval: function (ctx) {
-        return this.attrs ? this : new(tree.URL)(this.value.eval(ctx), this.paths);
+        var val = this.value.eval(ctx), rootpath;
+
+        // Add the base path if the URL is relative
+        if (typeof val.value === "string" && !/^(?:[a-z-]+:|\/)/.test(val.value)) {
+            rootpath = this.rootpath;
+            if (!val.quote) {
+                rootpath = rootpath.replace(/[\(\)'"\s]/g, function(match) { return "\\"+match; });
+            }
+            val.value = rootpath + val.value;
+        }
+
+        return new(tree.URL)(val, this.rootpath);
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/value.js b/build-tools/lib/less/tree/value.js
index 922096c..3c1eb29 100644
--- a/build-tools/lib/less/tree/value.js
+++ b/build-tools/lib/less/tree/value.js
@@ -21,4 +21,4 @@ tree.Value.prototype = {
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/build-tools/lib/less/tree/variable.js b/build-tools/lib/less/tree/variable.js
index 10f7c08..674ca8e 100644
--- a/build-tools/lib/less/tree/variable.js
+++ b/build-tools/lib/less/tree/variable.js
@@ -1,6 +1,6 @@
 (function (tree) {
 
-tree.Variable = function (name, index) { this.name = name, this.index = index };
+tree.Variable = function (name, index, file) { this.name = name, this.index = index, this.file = file };
 tree.Variable.prototype = {
     eval: function (env) {
         var variable, v, name = this.name;
@@ -8,17 +8,31 @@ tree.Variable.prototype = {
         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.file,
+                    index: this.index };
+        }
+        
+        this.evaluating = true;
 
         if (variable = tree.find(env.frames, function (frame) {
             if (v = frame.variable(name)) {
                 return v.value.eval(env);
             }
-        })) { return variable }
+        })) { 
+            this.evaluating = false;
+            return variable;
+        }
         else {
-            throw { message: "variable " + name + " is undefined",
+            throw { type: 'Name',
+                    message: "variable " + name + " is undefined",
+                    filename: this.file,
                     index: this.index };
         }
     }
 };
 
-})(require('less/tree'));
+})(require('../tree'));
diff --git a/src/themes/tizen/common/jquery.mobile.forms.textinput.less b/src/themes/tizen/common/jquery.mobile.forms.textinput.less
index faed987..56ea191 100644
--- a/src/themes/tizen/common/jquery.mobile.forms.textinput.less
+++ b/src/themes/tizen/common/jquery.mobile.forms.textinput.less
@@ -78,7 +78,7 @@ textarea.ui-input-text {
 }
 
 /* code for label+inputbox : remove this code if webApp dev. controls input area */
-@media all and (min-width: 721*@unit_base) {
+@media all and (min-width: 721px) {
 	label.ui-input-text:not([data-type='search']) {
 		vertical-align: top;
 		display: inline-block;
-- 
2.7.4