diff --git a/lib/ace/mode/behaviour/css.js b/lib/ace/mode/behaviour/css.js
new file mode 100644
index 00000000..fd1f4041
--- /dev/null
+++ b/lib/ace/mode/behaviour/css.js
@@ -0,0 +1,100 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Distributed under the BSD license:
+ *
+ * Copyright (c) 2010, Ajax.org B.V.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Ajax.org B.V. nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+define(function(require, exports, module) {
+"use strict";
+
+var oop = require("../../lib/oop");
+var Behaviour = require("../behaviour").Behaviour;
+var CstyleBehaviour = require("./cstyle").CstyleBehaviour;
+var TokenIterator = require("../../token_iterator").TokenIterator;
+
+var CssBehaviour = function () {
+
+    this.inherit(CstyleBehaviour);
+
+    this.add("colon", "insertion", function (state, action, editor, session, text) {
+        if (text === ':') {
+            var cursor = editor.getCursorPosition();
+            var iterator = new TokenIterator(session, cursor.row, cursor.column);
+            var token = iterator.getCurrentToken();
+            if (token && token.value.match(/\s+/)) {
+                token = iterator.stepBackward();
+            }
+            if (token && token.type === 'support.type') {
+                var line = session.doc.getLine(cursor.row);
+                var rightChar = line.substring(cursor.column, cursor.column + 1);
+                if (rightChar === ':') {
+                    return {
+                       text: '',
+                       selection: [1, 1]
+                    }
+                }
+                if (!line.substring(cursor.column).match(/^\s*;/)) {
+                    return {
+                       text: ':;',
+                       selection: [1, 1]
+                    }
+                }
+            }
+        }
+    });
+
+    this.add("colon", "deletion", function (state, action, editor, session, range) {
+        var selected = session.doc.getTextRange(range);
+        if (!range.isMultiLine() && selected === ':') {
+            var line = session.doc.getLine(range.start.row);
+            var rightChar = line.substring(range.end.column, range.end.column + 1);
+            if (rightChar === ';') {
+                range.end.column ++;
+                return range;
+            }
+        }
+    });
+
+    this.add("semicolon", "insertion", function (state, action, editor, session, text) {
+        if (text === ';') {
+            var cursor = editor.getCursorPosition();
+            var line = session.doc.getLine(cursor.row);
+            var rightChar = line.substring(cursor.column, cursor.column + 1);
+            if (rightChar === ';') {
+                return {
+                   text: '',
+                   selection: [1, 1]
+                }
+            }
+        }
+    });
+
+}
+oop.inherits(CssBehaviour, CstyleBehaviour);
+
+exports.CssBehaviour = CssBehaviour;
+});
diff --git a/lib/ace/mode/css.js b/lib/ace/mode/css.js
index cd66d37f..50b214c6 100644
--- a/lib/ace/mode/css.js
+++ b/lib/ace/mode/css.js
@@ -37,13 +37,13 @@ var Tokenizer = require("../tokenizer").Tokenizer;
 var CssHighlightRules = require("./css_highlight_rules").CssHighlightRules;
 var MatchingBraceOutdent = require("./matching_brace_outdent").MatchingBraceOutdent;
 var WorkerClient = require("../worker/worker_client").WorkerClient;
-var CstyleBehaviour = require("./behaviour/cstyle").CstyleBehaviour;
+var CssBehaviour = require("./behaviour/css").CssBehaviour;
 var CStyleFoldMode = require("./folding/cstyle").FoldMode;
 
 var Mode = function() {
     this.$tokenizer = new Tokenizer(new CssHighlightRules().getRules(), "i");
     this.$outdent = new MatchingBraceOutdent();
-    this.$behaviour = new CstyleBehaviour();
+    this.$behaviour = new CssBehaviour();
     this.foldingRules = new CStyleFoldMode();
 };
 oop.inherits(Mode, TextMode);
diff --git a/lib/ace/mode/less.js b/lib/ace/mode/less.js
index c926c15a..3a2ce733 100644
--- a/lib/ace/mode/less.js
+++ b/lib/ace/mode/less.js
@@ -36,11 +36,13 @@ var TextMode = require("./text").Mode;
 var Tokenizer = require("../tokenizer").Tokenizer;
 var LessHighlightRules = require("./less_highlight_rules").LessHighlightRules;
 var MatchingBraceOutdent = require("./matching_brace_outdent").MatchingBraceOutdent;
+var CssBehaviour = require("./behaviour/css").CssBehaviour;
 var CStyleFoldMode = require("./folding/cstyle").FoldMode;
 
 var Mode = function() {
     this.$tokenizer = new Tokenizer(new LessHighlightRules().getRules(), "i");
     this.$outdent = new MatchingBraceOutdent();
+    this.$behaviour = new CssBehaviour();
     this.foldingRules = new CStyleFoldMode();
 };
 oop.inherits(Mode, TextMode);
diff --git a/lib/ace/mode/scss.js b/lib/ace/mode/scss.js
index 372dfeb2..a0f4826f 100644
--- a/lib/ace/mode/scss.js
+++ b/lib/ace/mode/scss.js
@@ -36,11 +36,13 @@ var TextMode = require("./text").Mode;
 var Tokenizer = require("../tokenizer").Tokenizer;
 var ScssHighlightRules = require("./scss_highlight_rules").ScssHighlightRules;
 var MatchingBraceOutdent = require("./matching_brace_outdent").MatchingBraceOutdent;
+var CssBehaviour = require("./behaviour/css").CssBehaviour;
 var CStyleFoldMode = require("./folding/cstyle").FoldMode;
 
 var Mode = function() {
     this.$tokenizer = new Tokenizer(new ScssHighlightRules().getRules(), "i");
     this.$outdent = new MatchingBraceOutdent();
+    this.$behaviour = new CssBehaviour();
     this.foldingRules = new CStyleFoldMode();
 };
 oop.inherits(Mode, TextMode);