AUI/ S'rendarr Color Tweak (I think this is an easy question!)
 

Hey, I am entirely new to tweaking addons (and .lua files in general) but I'd love some help with what i think isn't a terribly hard goal: I would like to change the background color of the AUI and/or Srendarr buff bars from either no color at all (totally transparent frame) in the case of AUI or that sort of opaque blue in Srendaar to a complete, flat, jet BLACK, no gloss.

My eyes are not great and I'm losing track of whats going on on the buff bars thanks to background noise. Ideally I would toss the buff bar in a corner of the screen, and have the icons/timers appear (totally routinely,) just on a flat, black bar. I assume that I just need to change some hex's somewhere, but I don't even know where to start. I (and my crap eyes) would be very grateful for your help! Thanks in advance!