✓ 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 (min=0 at top maps to crowns in air, but `writing-mode: bt-lr` with `-webkit-appearance: slider-vertical` causes the physical thumb at top to correspond to max value on most browsers, making bottom=air), splash effects are stochastic rather than event-triggered, and crowns are drawn in fixed positions with size implying volume difference but the two crowns share the same Y-travel path so submersion depth is identical rather than crown2 entering water sooner due to larger radius.
Slider direction is inverted (min=0 at top maps to crowns in air, but `writing-mode: bt-lr` with `-webkit-appearance: slider-vertical` causes the physical thumb at top to correspond to max value on most browsers, making bottom=air), splash effects are stochastic rather than event-triggered, and crowns are drawn in fixed positions with size implying volume difference but the two crowns share the same Y-travel path so submersion depth is identical rather than crown2 entering water sooner due to larger radius.