Thread:Project:Support desk/Mediawiki 1.22.6 - Change white popup color

Good evening. I'm continuing to do more work on my wiki and am slowly but surely learning. I am trying to change the background color of the box that pops up when you click, say, Watch or Unwatch that is a notice box. I can't seem to find in documentation what that is, and I tried to use Inspect Element (which has helped immensely in skinning/customizing), but the box doesn't stay up long enough for me to go through the list for what I need.

Any help would be appreciated.