Light-on-Dark Text Needs Three Fixes

Light glyphs on a dark field optically bloom: the bright strokes spill into the surrounding dark, so the same type reads heavier and tighter than it does inverted. The concrete remedy is all three axes at once - line-height up by 0.05 to 0.1, letter-spacing up by 0.01em to 0.02em, and optionally one step of body weight - because fixing only one leaves the block feeling wrong without telling you why. Ship a single type spec for both themes and one of the two is always mis-set.