Is there any way to modify the CS theme? I would really enjoy setting it to use some colors that are a bit easier on my eyes, and even a little relief would go a long way.
With a hex editor maybe, but even then I'm not entirely sure. The best bet is to just tweak your windows theme and/or reducing your monitors brightness and contrast.
You might find some more themes in the OP of this thread: http://www.gamesas.com/index.php?/topic/1151506-post-your-desktop/.