✓ 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 (dragging down increases depth value from 0→100, but with writing-mode bt-lr the visual top corresponds to high values, making top=water and bottom=air); splash triggers only at discrete 10% intervals rather than at the actual water-surface contact point, and crowns move purely by Y-translation so they don't interact with the drawn water surface convincingly.
Slider direction is inverted (dragging down increases depth value from 0→100, but with writing-mode bt-lr the visual top corresponds to high values, making top=water and bottom=air); splash triggers only at discrete 10% intervals rather than at the actual water-surface contact point, and crowns move purely by Y-translation so they don't interact with the drawn water surface convincingly.