✓ 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/top = crowns in air is correct semantically but writing-mode/rtl/slider-vertical combo makes the visual top of the slider map to value=0, which may render as bottom depending on browser; no fall animation between frames — crown teleports — and mass/volume/density panels are static text, not live tspan updates tied to slider state.
Slider direction is inverted (value=0/top = crowns in air is correct semantically but writing-mode/rtl/slider-vertical combo makes the visual top of the slider map to value=0, which may render as bottom depending on browser; no fall animation between frames — crown teleports — and mass/volume/density panels are static text, not live tspan updates tied to slider state.