So you have problems with the input fields (and dropdown boxes)?
I think the problem is that you have edited the raidplanner.css file. You can make input boxes to inverse (black backgrounded) with:
.rp_container input, .rp_container select {
background: black;
color: white;
}
The character editor popup doesn’t load the template css files, so put this into raidplanner.css.
The other solution is not touching raidplanner.css, but add a white bakcground to popup windows with:
#sbox-content { background: white; }
Hopfully this helps you.