Forum Header Background Color & Custom Social Media Color

Hello!

I have two questions:

1) Where can I edit the background color of the header rows for the forums?
I made a change to the CSS which made the font black so it would be easier to read throughout the site, but my forum header currently has a black background as well, so it just blends in. I tried changing the custom theme settings for the site but none of them affected that setting.

2) Continuing off of this post, where we learned how to add custom social media links to the header and footer: How can we change the hover color? Right now the custom ones I made have no hover color, while the pre-installed ones do. How can I edit that?

Thank you!