Board Thread:Darwin/@comment-5275700-20131204234942/@comment-16101931-20131208021629

Try this: .mediawiki.ltr.ns-0 { background: url('http://images.wikia.com/gaia/images/3/3f/Overall_bg_clouds.png'); }

I tested this using my global.css and it seemed to work. It used that image on ns:0 on all wikis that I visited. The same thing should work (presumably) for any other namespace by just changing the 'ns-#'. If not, let me know, and I'll help you figure it out.