✓ 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/top=air maps correctly in value but the vertical-slider CSS with direction:rtl makes top=100/bottom=0 ambiguous — actual behavior sends crown down as value increases which is correct, but slider thumb starts at top with value=0=air which is correct); however, no smooth fall animation exists — crown teleports position via ASCII grid redraws, and the ASCII art approach severely limits visual polish and animation quality.
Slider direction is inverted (min=0/top=air maps correctly in value but the vertical-slider CSS with direction:rtl makes top=100/bottom=0 ambiguous — actual behavior sends crown down as value increases which is correct, but slider thumb starts at top with value=0=air which is correct); however, no smooth fall animation exists — crown teleports position via ASCII grid redraws, and the ASCII art approach severely limits visual polish and animation quality.