[sirmaru]

If the measure of black is the frame, then, yes, both the UI background and the white text on dark background have a charcoal grey background.

I never noticed until you brought up the question. I had interpreted it as black.

Having auto-brightness on will change brightness in the foreground and background. I keep mine at 50% constant so it never changes. Auto-brightness changes the light level every time you turn the unit's angle to the external light source.