thumbnail nav background color? Different nav styles?

Hi, I got the Revslider with my highend, here’s another question:

Is there a way to change the background color of a thumbnail navigation bar? Please see attached screenshot. Is that in a CSS file, if so can you tell me which one and point me at which lines to change? Also, aren’t there different styles of thumbnail nav bars to choose from? I thought I saw that, but can’t remember where.

Thanks!

PC, Win7 & Win8.1, Firefox