✓ 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 at top means crowns in air, but HTML vertical range sliders render min at bottom, so top of slider = max = water, which contradicts the label "Kronen oben" at top); mass/volume/density values are static labels, not live-updating; crowns lack a fall animation (they translate downward with no easing/tween distinct from the slider drag itself).
Slider direction is inverted (value=0 at top means crowns in air, but HTML vertical range sliders render min at bottom, so top of slider = max = water, which contradicts the label "Kronen oben" at top); mass/volume/density values are static labels, not live-updating; crowns lack a fall animation (they translate downward with no easing/tween distinct from the slider drag itself).