✓ 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 maps to crowns in air at top, which is correct for a standard range, but the `writing-mode: vertical-lr; direction: rtl` CSS rendering means visually the top of the slider corresponds to max/submerged — direction is ambiguous but likely wrong visually); animation is purely ASCII/text-based with no smooth fall animation, just discrete character redraws driven by slider position.
Slider direction is inverted (value=0 maps to crowns in air at top, which is correct for a standard range, but the `writing-mode: vertical-lr; direction: rtl` CSS rendering means visually the top of the slider corresponds to max/submerged — direction is ambiguous but likely wrong visually); animation is purely ASCII/text-based with no smooth fall animation, just discrete character redraws driven by slider position.