A gradient background now clips to the actual glyph-outline union under vertical-rl/vertical-lr, matching the horizontal case, instead of falling back to a plain border-box fill. The rotated column builds one outline per whole word, transformed into its physical footprint; the upright column builds one outline per character, translated to its own cell. The CJK column's font carries real OpenType vertical metrics (vhea/vmtx) - each upright character's outline is additionally clipped to its own reserved cell before being unioned in (issue #1194), so the gradient hugs the glyph ink tightly instead of falling back to a plain border-box fill the way this exact combination used to.