✓ 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 (label says "pull up to submerge" but slider min=0 is air and max=100 is water, which is bottom-to-top in a vertical slider — visually top=air, bottom=water is actually correct for a bt-lr slider, but the instruction text contradicts; additionally, mass/volume/density values are static (not live-updating), only displaced water updates dynamically, and splash coordinates during animation are miscalculated.
Slider direction is inverted (label says "pull up to submerge" but slider min=0 is air and max=100 is water, which is bottom-to-top in a vertical slider — visually top=air, bottom=water is actually correct for a bt-lr slider, but the instruction text contradicts; additionally, mass/volume/density values are static (not live-updating), only displaced water updates dynamically, and splash coordinates during animation are miscalculated.