Safari on a Mac wants the webkit prefix; Safari on iOS has no fullscreen for an ordinary
element at all, only for a <video>, so requestFullscreen was simply undefined and the tab
threw. It now uses whichever spelling the browser has, and where there is none the frame
fills the viewport in-page instead — the same result minus the browser's own chrome — with
a Done button and Escape to come back. The button reads Expand rather than Fullscreen when
that is what it will do.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
