✓ 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 — the hint label reads "▲ Luft / ▼ Wasser" but RTL vertical range input maps value=0 to the bottom, meaning dragging down increases pct and lowers the crown, which is logically correct visually yet contradicts the stated label; additionally the water-rise pixel scale is hard-coded rather than derived from tank geometry, making the visual rise disproportionate between the two crowns.
Slider direction is inverted — the hint label reads "▲ Luft / ▼ Wasser" but RTL vertical range input maps value=0 to the bottom, meaning dragging down increases pct and lowers the crown, which is logically correct visually yet contradicts the stated label; additionally the water-rise pixel scale is hard-coded rather than derived from tank geometry, making the visual rise disproportionate between the two crowns.