The cap-4 composite shipped the coach-mark sliced through the middle of its sentence.
Measured, same component and viewport: the leaf renders the pill at bottom 864 of 900,
the composite at 919 — clipped by 17px, because the composite adds a ~53px header above
its nested child's stage and findMapBox() finds no positioned container to re-parent into.
The component's header promises that case degrades to "stay put — a degraded anchor, never
a crash". A graceful degradation that degrades to invisible is a failure, not a fallback,
so the clamp measures the rendered rect and only ever lifts a pill that is actually clipped.
Two wrong attempts are recorded in the code because the reasons matter. Setting
style.transform would have destroyed the wrapper's translateX(-50%) centring, and the
pill's computed transform also carries the bob animation, so a computed reading is never
just my offset. Adjusting the bottom offset composes with the attribution clearance
instead of fighting it. Clamping only at nextTick also missed: the composite's layout has
not settled then, so the clamp now runs from syncAttribClearance, which already re-fires
from a ResizeObserver, plus a second observer on the pill's own layout parent.
Verified on six surfaces: the composite lifts 30px to bottom 888, every other surface
reports lift 0 and is byte-identical in behaviour, and all six keep centreDelta 0.
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