✓ 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 (writing-mode + direction:rtl maps value=0 to bottom, value=100 to top, so dragging down increases %, which is correct visually but the physical label "Ins Wasser senken" at top paired with 0% starting state makes the UX semantics confusing and non-standard); all physics, visuals, and features are otherwise well-implemented.
Slider direction is inverted (writing-mode + direction:rtl maps value=0 to bottom, value=100 to top, so dragging down increases %, which is correct visually but the physical label "Ins Wasser senken" at top paired with 0% starting state makes the UX semantics confusing and non-standard); all physics, visuals, and features are otherwise well-implemented.