[Theme: PageLines] Change Text Color in NavBar

I’m using the “Blue” Navbar, but want to change the color of the active and hover items. I’ve seen a couple of plugins which I installed, and they did not work. I also saw that I should add code to “custom.css” which is fine, but I only know enough to be dangerous, so need detailed instructions. I’ve used FireBug, and am still so confused I’m going cross-eyed. I know this has been answered before, but I’m still very confused. Help? Thanks.

http://pelicanwalkrentals.com/pwalk

http://wordpress.org/extend/themes/pagelines/