✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns ✓ Slider direction correct ✓ Full slider range — Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects — Physics correct ✓ Live mass value ✓ Live volume value — Live density value ✓ Live displaced water ✓ Gilded displaces more ✓ Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Displacement calculation is broken — it reads crown Y from a stale `data-y` attribute rather than actual submerged ratio, so displaced-water values stay near 0 and water level barely rises; density is displayed as static label text, not a live computed value, and there is no smooth fall animation (crowns teleport via CSS transform).
Displacement calculation is broken — it reads crown Y from a stale `data-y` attribute rather than actual submerged ratio, so displaced-water values stay near 0 and water level barely rises; density is displayed as static label text, not a live computed value, and there is no smooth fall animation (crowns teleport via CSS transform).