Five of them sit where round 6 turned F from a Fullscreen API call into a CSS
maximise: the guards around it still asked `isFullscreen`, which that pivot made
permanently false.
- Arrow-key volume was dead in the maximised view: the scroll-deference checked
only `isFullscreenRef`, so the (now hidden but still scrollable) card kept
swallowing Up/Down. Both flags now count as "the video fills the screen".
Measured: 87px of scroll room on the focused card, ArrowDown moves 80 -> 75
and scrolls nothing.
- The maximised view had no way out once the pointer touched the video. Reaching
YouTube's controls means clicking into the cross-origin iframe, which takes
keyboard focus with it, and the re-arm paths (stage mouseleave, window focus)
need the pointer to leave the browser entirely while the stage fills it. So
the exit now lives on screen, in our DOM: a button that un-maximises AND pulls
focus back, re-arming every shortcut.
- WebKit fires only `webkitfullscreenchange`/`webkitFullscreenElement`, so on
Safari/iPadOS YouTube's own fullscreen never registered — no overlay yield, no
focus reclaim. One `fullscreenEl()` reader, both event spellings.
- The stage claimed `z-index: 9999`, the glass tuner's reserved level, for a job
that only needs to beat the modal chrome it is nested in (its siblings top out
at z-menu). Dropped to rail-level; nothing escapes the modal's stacking
context either way.
- `inset: 0` already sizes a fixed layer — the inherited `100vw`/`100vh`
over-constrained it, which is how a classic scrollbar gets a horizontal
overflow and a mobile URL bar hides the bottom edge (YouTube's control bar).
- The shortcut hint still promised "F: fullscreen" in both locales.
Backend, both "the fix stopped one layer short":
- The startup HLS sweep was awaited inside lifespan, so uvicorn still served
nothing until it finished — a thread doesn't help when nothing is listening
yet. Fire-and-forget task instead, cancelled on shutdown. Measured with 200
planted segments: "Application startup complete" now precedes "swept 1".
- An RSS poll where every channel failed returned normally, so the scheduler
recorded `ok` with the outage buried in the summary string. `failed == total`
now raises: a run that reached nothing is a failed run.
Suites: backend 147 -> 150.
peter
a5336d20e0