If you know any basic CSS, you can change the apperence to whatever you like the 'Stylish' plugin for Chrome and Firefox. https://userstyles.org/
I use it for a ton of websites, and enjoy playing with it, but not Warlight. So if you want to write a theme for it you're on your own I'm afraid.
Edit: I don't think anything aside from the dashboard and game-creation pages has changed since 2011, the overall theme has always been the same.
Edited 12/18/2014 14:46:47