The player is `fixed left-0 top-0 z-50` but rendered from inside the page
scroller, so it only ever covered the viewport because that scroller happened
not to be a stacking context. Giving it the edge-fade made it one, and the mask
scoped the player's z-50 inside it: the rail, the side panel and the header
painted straight over the player, and its edges faded. Measured both ways, then
fixed where every other full-screen overlay here already sits — <body>.
Same for the Suspense fallback that stands in while the player chunk loads, and
for the floating draft save bar on the Configuration page. Swept the rest: every
other `fixed` element is either App-level or already portaled.
peter
9b4ee83ec8