✓ 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 is top/air, value=100 is bottom/water, but HTML range inputs render 0 at the bottom for vertical sliders, so the visual direction is reversed); mass/volume/density values are static display only (not live-updating), and the crown movement lacks smooth falling animation — it teleports based on slider position with no keyframe physics.
Slider direction is inverted (value=0 is top/air, value=100 is bottom/water, but HTML range inputs render 0 at the bottom for vertical sliders, so the visual direction is reversed); mass/volume/density values are static display only (not live-updating), and the crown movement lacks smooth falling animation — it teleports based on slider position with no keyframe physics.