Thing is, I want to change the color of (I don't even know the name!) you know, where the category names are put. And same but with the forums.

Maybe it's easy as hell, but I don't know nothing about HTML... By now I've managed to do a few changes following the "change-something-and-and-see-what-happens" method.

Please just tell me WHERE are the color codes I must substitute for my own color choice.
Thank you in advance.