I use my own color scheme in windows XP (a reversed one: white letters on a black background), and since upgrade to 0.3, buttons (like "new", "reply", ...) are no longer visible. They are there, and work fine, but they are not visible. (In the previous version 0.2.x those buttons were visible, even with my own color scheme)
This doesn't happen for me, what css are you changing?
In Opera 9.2 I use a my own custom css. I will try out another one. Probably it's due to my own setting then, as you are able to view the buttons with a another color scheme.
In IE and Firfox, I don't use a css I think. In those browsers, I just tick some boxes (in the color setting preferences).
Now I know it is possible to view those buttons, I will experiment a bit with my settings, and let you know the result.