✓ 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 maps to crown in air correctly via depthPct=0, but the vertical slider renders with min at top visually, so dragging toward "UNTEN/Tief" raises value correctly — however the `writing-mode: vertical-lr; direction: rtl` setup makes min=0 appear at top, which is actually correct directionally; the animation loop runs at 80ms ticks but crown movement is purely slider-driven with no autonomous fall animation between frames, so "fall animation" is absent as a distinct effect.
Slider direction is inverted (value=0 at top maps to crown in air correctly via depthPct=0, but the vertical slider renders with min at top visually, so dragging toward "UNTEN/Tief" raises value correctly — however the `writing-mode: vertical-lr; direction: rtl` setup makes min=0 appear at top, which is actually correct directionally; the animation loop runs at 80ms ticks but crown movement is purely slider-driven with no autonomous fall animation between frames, so "fall animation" is absent as a distinct effect.