✓ 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 with correct physics (gold 19.3 g/cm³, gilded 13.0 g/cm³, same 1000 g mass, larger volume displaces more), but mass/volume/density info panels are static text rather than truly live-updating values, and the water rise scale factor (PX_PER_CM3=0.55) makes the displacement difference visually subtle rather than dramatic.
All required features are implemented with correct physics (gold 19.3 g/cm³, gilded 13.0 g/cm³, same 1000 g mass, larger volume displaces more), but mass/volume/density info panels are static text rather than truly live-updating values, and the water rise scale factor (PX_PER_CM3=0.55) makes the displacement difference visually subtle rather than dramatic.