Mozilla's GUI (non)conformity

I use Plasma & XFCE depending on the booted distro and most non-KDE apps konform at least to some extent with the KDE desktop when KDE is used examples being Pan, Sylpheed, gftp and even nedit. The ONE set that is almost always problematic is anything Mozilla, Firefox in this particular case. I cannot change the title bar from black which just makes it impossible to distinguish from darker wallpapers, there being no way to select something with a contrasting window border either. How can I fix this?