How do I change a usergroup's title color and font weight?

[edgeless]

My version is 4.2.0 and I'm currently using postbit_legacy format.

This should be such a simple thing to achieve (and it probably is). I'm trying to change the usergroup title colors (as they are displayed underneath the user names and above the avatars within posts). The method for changing the markup color for the user names within a usergroup is clearly documented among numerous posts here and quite easy to accomplish with the Usergroup Manager. But I can't seem to find a way to change the usergroup title colors and font weights. No matter what I've tried so far they remain black and un-bolded. Will someone please point me to the solution?

Thank you.