✓ 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
Solid ASCII-art demo with correct physics (gold 19.3 g/cm³, gilded 10.5 g/cm³, same 1000 g mass) and live readouts, but the vertical slider renders horizontally in most browsers (writing-mode/appearance trick is unreliable) and is directionally inverted (0=crowns in air is at the bottom of the slider track, matching standard range-input convention but opposite to the required top=air/bottom=water spec for a proper vertical control).
Solid ASCII-art demo with correct physics (gold 19.3 g/cm³, gilded 10.5 g/cm³, same 1000 g mass) and live readouts, but the vertical slider renders horizontally in most browsers (writing-mode/appearance trick is unreliable) and is directionally inverted (0=crowns in air is at the bottom of the slider track, matching standard range-input convention but opposite to the required top=air/bottom=water spec for a proper vertical control).