I don't know that skin very well, but if you do a view source on your page you will see all the classes that eventually make certain text be dim. You then go to your css sheet and search for the right combination of classes that match where the dim stuff was and make the appropriate changes.

I took a quick look at your source and am pretty sure you are looking for "menu li li" or maybe "menu ul ul". I think it's "menu li li" but without going into the style sheet it's hard to say. Also, it might not have the menu part in it - it might just say "li li { lots of stuff }", but since they are inside a menu div they would also have to listen to the menu rules. Depends on how the author wanted to write the styles, so you just have to poke around a bit and see happens when you make changes.

A nice way to see if you are affecting the right piece is to add "border: 1px solid red;" to any given definition and see if the part you're after gets a thin red border around it. If so then take the border out and make the changes you need. If not move your thin red line somewhere else.