apply 'cp' class for unified styles

www/code/index.html

@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html class="cp code">
 <head>
     <meta content="text/html; charset=utf-8" http-equiv="content-type"/>
     <script data-main="main" src="/bower_components/requirejs/require.js"></script>