Full-screen takeover

:effect takeover renders the built-in effect full-screen behind the whole page, using a single persistent canvas that survives navigation (only reconfigured, never recreated, as you move between pages) rather than an inline window. A small floating play/stop panel appears while a takeover is active. Pair it with :hidden so only the background shows:

Look at the page background rather than this spot, then navigate away to another chapter to see it switch off (the persistent canvas stays alive, just idle), and back to see it return.