The initial refresh() ran before the mobile layout settled (media queries,
fonts, async highlighting) and under-measured the content, leaving #jumpnav
hidden on long pastes at 375x812 until a resize event. Re-check after a
double rAF, on window load, after 300ms, and via a ResizeObserver on
document.body for late content growth. Editor textarea scroller unchanged.
Fixed-position Top/Bottom pills appear only when content exceeds 2x
viewport height (window scroll on paste view, textarea scroll on /new).
New static/jump.js drives them; markup added to paste.html and new.html.
fen