What is the file and class to edit for changing background colors?

I am trying to edit the background color of my superfish menu but am confused as to which file and class I'm supposed to edit.

All the other issues I've come across mention editing a `.superfish-inner .menu li` class or a `#menu-bar` id but i cannot find the second id. I've tried editing the class, but that doesn't do anything.

When inspecting the menu with Firebug, it points to the file: space-teal.css
Is that normal?