✓ 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 crowns in air, but the label "Luft" is at top with min=0, and immersion uses (100 - immersionPercent) — actually crowns start in air at value=0, but slider-vertical on most browsers has min at bottom, making it effectively inverted UX; ASCII-art rendering is glitchy (both crowns share the same horizontal position and overlap rather than rendering side-by-side distinctly), and no splash effects are implemented.
Slider direction is inverted (value=0 at top maps to crowns in air, but the label "Luft" is at top with min=0, and immersion uses (100 - immersionPercent) — actually crowns start in air at value=0, but slider-vertical on most browsers has min at bottom, making it effectively inverted UX; ASCII-art rendering is glitchy (both crowns share the same horizontal position and overlap rather than rendering side-by-side distinctly), and no splash effects are implemented.