✓ 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 label says "▲ hoch / ▼ tief" and value=0 starts crowns in air, but writing-mode+direction:rtl on a vertical range makes the physical top of the slider correspond to value=100 (water), not value=0 (air), so dragging up submerges the crowns rather than lifting them.
Slider direction is inverted — the label says "▲ hoch / ▼ tief" and value=0 starts crowns in air, but writing-mode+direction:rtl on a vertical range makes the physical top of the slider correspond to value=100 (water), not value=0 (air), so dragging up submerges the crowns rather than lifting them.