✓ 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
Physics values are unrealistic (gold density 20.0 g/cm³ instead of ~19.3, gilded at 10.0 g/cm³ is plausible but water-rising math is a broken re-assignment loop each draw call), and slider direction is inverted (min=0/top=air is correct by default for vertical sliders rendered with -webkit-appearance:slider-vertical, but the mapping sets value=0→crowns at top/air and value=100→crowns down, which is actually correct directionally — however the slider thumb physically sits at the bottom when value=0 in -webkit-appearance:slider-vertical, making the UX feel inverted to the user).
Physics values are unrealistic (gold density 20.0 g/cm³ instead of ~19.3, gilded at 10.0 g/cm³ is plausible but water-rising math is a broken re-assignment loop each draw call), and slider direction is inverted (min=0/top=air is correct by default for vertical sliders rendered with -webkit-appearance:slider-vertical, but the mapping sets value=0→crowns at top/air and value=100→crowns down, which is actually correct directionally — however the slider thumb physically sits at the bottom when value=0 in -webkit-appearance:slider-vertical, making the UX feel inverted to the user).