Create a configure option to override the menu's color for different regions

We're using a multi region setup with Openstack. When the users uses the frontend, they sometimes get confused, which region they're using.
We did some branding in the UI with css (replacing color of h1.brand) which works fine, however the css should contain some region dependent brandig somehow.

I'm not familiar with the codebase, so I cannot provide any tips/ideas, how you should do it.