MediaWiki:Monobook.css

 /* edit this file to customize the monobook skin for the entire site */

 body {
   font-size: 10px;
   font-family: verdana, geneva, arial, helvetica, sans-serif;
   background-repeat: repeat-x;
   background-color: #EBEBEB;
 }

 .portlet {
   width: 12em;
 }

 #content {
   margin-left: 12.6em;
 }