I have tried to get ATOM to format nice with XSL with nearly no success. So I switched to CSS. It works! Almost. IE6 doesn't render it properly, which is annoying, as I have been a defender of IE for years. IE7 should do fine.
If you'd like my CSS file, note the xml-stylesheet tag in the XML and grab it. If you don't know how, then you don't really need it, do you.