✓ 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 at top = crowns in air is correct by convention but the slider renders with 0 at bottom in vertical mode, effectively reversed), and no smooth fall animation — crowns teleport rather than fall.
Slider direction is inverted (value=0 at top = crowns in air is correct by convention but the slider renders with 0 at bottom in vertical mode, effectively reversed), and no smooth fall animation — crowns teleport rather than fall.