✓ 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 (label says top="drain water", bottom="submerge", and value=0 starts crowns near top/air while value=100 moves them to water — semantically backwards per spec); no fall animation (crowns teleport linearly with no drop/gravity motion); splash effects fire continuously during slider movement rather than on water entry impact only.
Slider direction is inverted (label says top="drain water", bottom="submerge", and value=0 starts crowns near top/air while value=100 moves them to water — semantically backwards per spec); no fall animation (crowns teleport linearly with no drop/gravity motion); splash effects fire continuously during slider movement rather than on water entry impact only.