✓ 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 at top = crowns in air is correct for `writing-mode: bt-lr` but the visual label "Luft" is at top and "Wasser" at bottom, which maps correctly, however the crown movement starts at crownStartY=-80 at depth=0 meaning crowns BEGIN in air — direction is actually correct on re-analysis; BUT fall animation is absent since crowns teleport via CSS transform with no smooth drop sequence, and the water-rise calculation divides by tankArea (200×350=70000 px²) making the water-level change nearly imperceptible (~0.00026 px increase per cm³), severely undermining the visual displacement effect.
Slider direction is inverted (value=0 at top = crowns in air is correct for `writing-mode: bt-lr` but the visual label "Luft" is at top and "Wasser" at bottom, which maps correctly, however the crown movement starts at crownStartY=-80 at depth=0 meaning crowns BEGIN in air — direction is actually correct on re-analysis; BUT fall animation is absent since crowns teleport via CSS transform with no smooth drop sequence, and the water-rise calculation divides by tankArea (200×350=70000 px²) making the water-level change nearly imperceptible (~0.00026 px increase per cm³), severely undermining the visual displacement effect.