✓ 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" at top, max=100 labeled "Wasser" at bottom, but HTML range inputs render vertically with writing-mode:vertical-lr/direction:rtl causing the 0 end to appear at bottom in most browsers), and crown movement has no autonomous fall animation — only slider-driven repositioning with no inertia or drop physics.
Slider direction is inverted (min=0 labeled "Luft" at top, max=100 labeled "Wasser" at bottom, but HTML range inputs render vertically with writing-mode:vertical-lr/direction:rtl causing the 0 end to appear at bottom in most browsers), and crown movement has no autonomous fall animation — only slider-driven repositioning with no inertia or drop physics.