Acceptance Criteria
overlay is constrained to none|dark|light (+ optional token reference / opacity).- A structured
scrim facet provides legibility behind overlaid text via scrim-type (gradient default | frost), scrim-strength, scrim-blur, scrim-tone (dark|light, explicit), targeting the bg overlay or the media well (SPEC-087 routing). scrim-tone sets the overlaid content's foreground polarity (text/muted tokens), not just the wash — a dark scrim yields light text — so text colour follows the scrim, not the base surface.- The unvalidated raw-string
overlay passthrough is deprecated with a build warning for one minor then removed, gated on scrim shipping.
Approach
overlay passthrough in engine.ts. Cover-mode scrim consumer is SPEC-089. SPEC-088 §3.