Forum:Custom Theme requires code

I want to take the Wikipedia Monobook css code and change it a bit to make it the default. How do I do that? Rsrealm Talk Guestbook  21:05, September 23, 2010 (UTC)
 * You can't - sorry -- Random Time  21:38, September 23, 2010 (UTC)
 * I'll find out.. Rsrealm Talk Guestbook   22:39, September 23, 2010 (UTC)
 * Found it. Rsrealm Talk Guestbook   22:42, September 23, 2010 (UTC)