✓ 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
Slider direction is inverted (value=0/top→air, value=100→water correct semantically, but `-webkit-appearance: slider-vertical` with `writing-mode: bt-lr` means the thumb physically starts at the bottom for value=0, making "air" at bottom and "water" at top visually); splash particles reference an undefined `newWaterHeight` variable (ReferenceError kills the splash effect entirely); no smooth fall animation—crowns teleport via CSS `top` without transition easing; Heureka and physics data are solid highlights.
Slider direction is inverted (value=0/top→air, value=100→water correct semantically, but `-webkit-appearance: slider-vertical` with `writing-mode: bt-lr` means the thumb physically starts at the bottom for value=0, making "air" at bottom and "water" at top visually); splash particles reference an undefined `newWaterHeight` variable (ReferenceError kills the splash effect entirely); no smooth fall animation—crowns teleport via CSS `top` without transition easing; Heureka and physics data are solid highlights.