(Theme: Stained Glass) Custom changes to navigation menu

I am just getting started creating my website and have installed multisite to run my network. I plan to have 1 landing page for my main domain, and 3 subdirectories for each of the 3 components to my brand (these 3 will run the same theme – Stained Glass).

Right now I have it set up so that there are 2 top navigation menus. I want to use the top menu to link to each subdirectory, and the bottom menu for the pages associated with the corresponding subdirectory.

What I want is to edit the top menu. I want it so that the button for the subdirectory you are currently on has a black background and white text so that you can clearly see which directory you are visitng. When you hover over one of the other buttons I want the hovered item to have a black background with white text, and have the current viewing directory button switch to having no background and black text making it look unselected. Not sure if that makes sense.

Is that even possible? Can someone please advise me on how I can achieve this?

This is a link to each of my subdirectories:
http://www.thewildhippies.com/designs
http://www.thewildhippies.com/boutique
http://www.thewildhippies.com/graphics
I do have the menu items on each directory ordered so that the button for the directory you are currently on is first in the list — this is the one that need to appear selected while on the site, unless you are hovering over the other directory buttons. Not sure if that makes a difference.