✓ 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
All required features are implemented cleanly with correct physics (ρ_gold=19.3, ρ_gilded=13.0, same 1000 g mass, proportional displacement), particle splash, rising water, and a fade-in HEUREKA at slider maximum; minor flaw is that buoyancy/displacement values use the base water surface for submerged-fraction calculation rather than the dynamically risen surface, slightly underestimating submersion depth during transition.
All required features are implemented cleanly with correct physics (ρ_gold=19.3, ρ_gilded=13.0, same 1000 g mass, proportional displacement), particle splash, rising water, and a fade-in HEUREKA at slider maximum; minor flaw is that buoyancy/displacement values use the base water surface for submerged-fraction calculation rather than the dynamically risen surface, slightly underestimating submersion depth during transition.