Two-layer defense for the recurring "black screen during playback"
bug class (5+ occurrences in 24h per doc 26/28/30):
L1 (prevention): scope every black-bg rule with
:not(:has(.htmlVideoPlayer)):not(:has(#videoOsdPage)) so the rules
self-disable while a player is in the DOM. Covers body,
#reactRoot, .skinBody, .backgroundContainer, .mainAnimatedPage,
.mainAnimatedPages, .pageContainer.
L2 (override): when JS-toggled body.arrflix-video-active is set,
high-specificity (0,3,2 + tag) transparent rule wins against any
ancestor opaque-bg rule (including future regressions someone adds
without scoping). Covers all known wrappers, the
videoPlayerContainer + videoPlayerContainer-onTop, #videoOsdPage,
.libraryPage, .htmlVideoPlayer.
L3 (z-index lift): force .htmlVideoPlayer + child <video> to
z-index:9999 + isolation:isolate during playback so it floats above
any opaque ancestor that still leaks through.
Verified in playwright: with arrflix-video-active + .htmlVideoPlayer
mounted, all 7 ancestors return rgba(0,0,0,0). Without — all 7
return rgb(0,0,0). Self-disabling works.
Lesson reinforced (doc 30 roadmap open): add darkPct assertion to
bin/headless-test-v2.py + xmllint CI gate. Five recurrences without
those gates says we keep relearning this. TODO next.
s8n
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