[style]
body{padding:10px;font-weight:normal;font-family:"geneva",arial,"helvetica",sans-serif;background:url('/your_picture.gif') no-repeat fixed center;margin:0}
.rw,.body,.inpt,.flg,.cmnt,th,comment,.flg,.inbtn,.col{background:#fff}
.col,body,.rw,.body,#hm{color:#039}
To change the icons:
Looking for anything that starts with src="/~
You replace the one you want by an image file of your Virtual File System (<img src"=/path_of/myicon.png">.)
Depending on the context of your tpl:
src="/myicon.png"
or
<img src="/myicon.png">