Question about font awesome

Hello

I'm creating a theme for first time on my life ( :noh: ) so I started by adding font awesome.

Now, I want to know how can I change the color of the icons (like here on NBB) but I don't want to see the code because then linkz is gonna say that I'm ripping stuff here and I don't want that.

Also, I'd love to know how to change the font at least on the header, actually it looks like this



Thank you so much :D