In iOS WebKit standalone (home screen) mode, position:fixed elements
move with the page when the body itself becomes scrollable - unlike
regular Safari where fixed elements stay pinned. The root cause was
body having min-height: 100dvh without overflow: hidden, which allowed
body scroll to occur when content overflowed.
Fix: html and body are now overflow: hidden with fixed height (100% / 100dvh)
so all scrolling is confined to .app-content. Service worker bumped to
shell-v30 to force re-download of reset.css on installed PWAs.
Ulas
3bc926d766