Changing the font color on the submit buttons?

I'm trying to change the font color on the various submit buttons of the Amadou theme, which doesn't seem to work out... The thing is, that my background in black, and the default font on the buttons is black as well, so you can't actually see anything! and not only is the font on the button black, but also the font that is entered in the submit fields (let's say, my username and pass. I can't see what I type - it's black on black)...

Please help...

Thanks a bunch

Lihi