Change aspect buttons bbPress

Hello,

I’m trying to modify aspect of bbPress installed in my wordpress. I’ve read diferents posts but I can’t find the solution.

http://codex.bbpress.org/layout-and-functionality-examples-you-can-use/

I need to change aspect buttons in bbPress because of font color and layout are similar and you can’t distinguish them.

http://i.imgur.com/71FmGz2.jpg

Could anyone help me or give me a clue to resolve this issue?

I use Rush theme and wordpress 3.9.1

http://www.escolasantmartibcn.cat/?forum=escola

Thank you