✓ 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 (dragging down increases value from 0→100 but the CSS `direction:rtl` + `writing-mode:vertical-lr` combo makes the top of the slider correspond to value=100/submerged rather than air, conflicting with the label "▲ oben / ▼ unten"); physics values (gold 19.3 g/cm³, copper 8.9 g/cm³, same 1000 g mass) are accurate and the ASCII scene correctly shows the gilded crown displacing more water, but there is no smooth falling animation — crown position jumps discretely with slider movement only.
Slider direction is inverted (dragging down increases value from 0→100 but the CSS `direction:rtl` + `writing-mode:vertical-lr` combo makes the top of the slider correspond to value=100/submerged rather than air, conflicting with the label "▲ oben / ▼ unten"); physics values (gold 19.3 g/cm³, copper 8.9 g/cm³, same 1000 g mass) are accurate and the ASCII scene correctly shows the gilded crown displacing more water, but there is no smooth falling animation — crown position jumps discretely with slider movement only.