✓ 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 (slider label says "unten = eingetaucht" confirming bottom=submerged, but the range input with writing-mode/direction CSS means dragging down increases value which maps to submersion — technically matching the label but counter to the spec's "top=air, bottom=water" for natural vertical sliders; no continuous fall animation, only instant positional lerp on input events.
Slider direction is inverted (slider label says "unten = eingetaucht" confirming bottom=submerged, but the range input with writing-mode/direction CSS means dragging down increases value which maps to submersion — technically matching the label but counter to the spec's "top=air, bottom=water" for natural vertical sliders; no continuous fall animation, only instant positional lerp on input events.