✓ 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 (min=0 labeled "Luft" maps to crowns in air, but the HTML labels hint "▲ Luft / ▼ Wasser" while vertical range inputs with writing-mode:vertical-lr/direction:rtl render max at top — so the visual top of the slider actually corresponds to value=100 (water), not value=0 (air), making the physical direction backwards from the label intent; also no autonomous fall animation — crown only moves when slider is dragged.
Slider direction is inverted (min=0 labeled "Luft" maps to crowns in air, but the HTML labels hint "▲ Luft / ▼ Wasser" while vertical range inputs with writing-mode:vertical-lr/direction:rtl render max at top — so the visual top of the slider actually corresponds to value=100 (water), not value=0 (air), making the physical direction backwards from the label intent; also no autonomous fall animation — crown only moves when slider is dragged.