add some more custom config and put every thing in comment in the custom.yaml template
/*
Copyright (c) 2009, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 3.0.0
build: 1549
*/
body{font:13px/1.231 arial,helvetica,clean,sans-serif;*font-size:small;*font:x-small;}select,input,button,textarea{font:99% arial,helvetica,clean,sans-serif;}table{font-size:inherit;font:100%;}pre,code,kbd,samp,tt{font-family:monospace;*font-size:108%;line-height:100%;}