Top Layer
Camouflage UI rendered in the browser top layer (Popover API and <dialog>.showModal()).
A Chameleon tour step, tooltip or survey shown after an overlay opens should render in front of it and stay clickable.
Open an overlay
Open at load (before any step shows): ?open=share, ?open=share,toast, ?open=menu, ?open=dialog, ?open=zindex.
Open later: &late=share&late_ms=5000.
Simulate a browser without the Popover API: &nopopover=1.
Plain page content
Outside every overlay
z-index overlay
High z-index, no Popover API — the pre-top-layer baseline.