Idea from UAT-2: give the feeds the same 'content behind glass' lift the Plex
detail page gets. New FeedBackdrop paints a faint, slowly-rotating feed thumbnail
as a fixed backdrop on <main> (the proven art-backdrop path — a fixed z:-1 layer
is occluded by the root's opaque bg-bg). Blur = tiny-canvas downscale + cover
upscale (no CSS filter; ytimg is CORS-readable so it uses a data-URL, else raw).
Flat --bg stays as the 'perf mode' look. Behind the GlassTuner toggle + a
Backdrop-fade slider (--feedbg-fade) so it's judged/tuned in UAT before anything
is committed for real.
peter
e1b8916be4