✓ 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, max=100 at bottom maps to crowns in water — actually correct in mapping but the native vertical range slider renders with 0 at bottom on most browsers, meaning the "Oben" label is at the top while 0/air position is visually at the bottom, causing directional confusion); otherwise physics, visuals, and feature completeness are strong.
Slider direction is inverted (min=0 at top maps to crowns in air, max=100 at bottom maps to crowns in water — actually correct in mapping but the native vertical range slider renders with 0 at bottom on most browsers, meaning the "Oben" label is at the top while 0/air position is visually at the bottom, causing directional confusion); otherwise physics, visuals, and feature completeness are strong.