✓ 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 the vertical range input's visual top corresponds to its minimum, which here means air — actually the range input with writing-mode bt-lr should make bottom=min=air, top=max=water, making the direction wrong); no discrete fall animation sequence — crowns slide linearly with no kinematic drop event, and splash particles fire continuously rather than on entry impact.
Slider direction is inverted (min=0 at top maps to crowns in air, but the vertical range input's visual top corresponds to its minimum, which here means air — actually the range input with writing-mode bt-lr should make bottom=min=air, top=max=water, making the direction wrong); no discrete fall animation sequence — crowns slide linearly with no kinematic drop event, and splash particles fire continuously rather than on entry impact.