Question: Border?

I've noticed people making beautiful borders on their signatures, and I was wondering on how to do that. You know, like the purple background behind the text on some Challenge threads, i.e. The Nervous System Challenge thread? I was just wondering.

They're using CSS. There's actually a help thread with links to tutorials and templates, it's worth a look. c: http://www.pokecommunity.com/showthread.php?t=200899