var ss = document.createElement("link");
ss.type = "text/css";
ss.rel = "stylesheet";
ss.href = "styles/main.css";

var iframe;
if(document.frames)
	iframe = document.frames["contentarea"];
else
	iframe = window.frames["contentarea"];
if(document.all)
	iframe.document.createStyleSheet(ss.href);
else
	iframe.document.getElementsByTagName("head")[0].appendChild(ss);