Improve demos/CSSLintDemo.htm.

Add default font and color for warning.

Author: XhmikosR

demos/CSSLintDemo.htm

@@ -4,7 +4,9 @@
     <meta charset="utf-8">
     <title>CSSLint Demo</title>
     <style>
-        .error { color: red; }
+        html { font: 14px sans-serif; }
+        .error { color: #D9534F; font-weight: bold; }
+        .warning { color: #F0AD4E; }
     </style>
     <script src="../release/csslint.js"></script>
 </head>