he stereo we ordered (a Jensen CD, DVD player) is permanently lighted and its pretty bright.
If you can't find a method to actually dim the panel, a pain-in-the-butt solution would be to make a cover for it using neutral density theatrical color media (it looks like it could be slipped into the fold down faceplate). "Gel" is sold by theatrical suppliers in 22" X 24" transparent Polyester sheets for around $7.50 per sheet & is available in over 100 colors, including various amounts of grey (ND filters) that don't change the color but cut down the light.
Lee Color Filters
or RoscoLux Color Filters
If you hit the theatrical supplier when they are in a good mood they will give you a "Swatch" book, a 1.75" x 2.75" collection of all their colors. For a bit more they sell a larger 3" X 5" swatch book for around $20.00. Either can be placed in fixtures to tame down the color of too white lamps, and include frosts that can soften harsh light sources.