Hi Lavellotron, there are a couple of moi.css files for v3 dark UIs that I ported over to v4 here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=10011.142
http://moi3d.com/forum/index.php?webtag=MOI&msg=6507.309

give those a try.

- Michael