✓ 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 maps to crowns high in air but HTML range inputs default top=max, so rtl/vertical-lr means bottom=0=air, top=100=water — opposite of spec); no smooth fall animation, crown positions jump discretely with slider.
Slider direction is inverted (value=0 at top maps to crowns high in air but HTML range inputs default top=max, so rtl/vertical-lr means bottom=0=air, top=100=water — opposite of spec); no smooth fall animation, crown positions jump discretely with slider.