Fix stylesheet link

Author: fantasai

css3-ruby/Overview.html

@@ -31,7 +31,7 @@
   </style>
 
 
-<link href="default.css" rel="stylesheet" type="text/css" />
+<link href="../default.css" rel="stylesheet" type="text/css" />
 
 <link href="http://www.w3.org/StyleSheets/TR/W3C-ED" rel="stylesheet" type="text/css" />