The near-black #120C12 behind the icon reads as black on dark home
screens, and the same fill backs the store icon, feature graphic and
README logo. Raise it to a plum #2D1C2D (L* 4.6 -> 13.1) so the
background is visible without costing the #F862F8 foreground its
contrast. The amber nightly background moves from #1A1200 to #2E2000 by
the same lightness step, so it stays amber instead of drifting to
brown-black.
Raster assets were recoloured from the committed originals; the vector
sources in images/ have no background and are unchanged.
austinried