- clearer glass (0.4 by default), denser toward the bottom right where
the equalizer labels and presets sit (fill alpha 0.55x / 1x / 1.6x)
- a white specular gradient: bright at the top left, a faint return at
the bottom right; a 1.5 px light rim that warms to the theme's flame
colour when hovered
- keeps the soft accent glow, as if the glass took the wallpaper's colour
- docs/design: board at glass 0.25 / 0.4 / 0.55, and the card at 0.4
