Detail bodies fill 100vh below the nav so the visualizer reads full-screen; Theater toggle eases page content and the player-bar now-showing panel in/out instead of popping (reduced-motion honored); Theater only applies to the currently-playing release.
Toggle left of the lava popover hides release content so the visualizer fills
the surface; player bar grows to carry the playing release's cover, title, and
share. State on WaveformVisualizerControlState; pages and bar observe it.