✓ 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 is top/air, value=100 is bottom/water, but writing-mode+direction:rtl means visually dragging down increases value, which maps to submerging — however the label reads "SENKEN" at top and "⬆ HOCH" at bottom, suggesting the layout intent is correct but the fall animation is absent (crowns teleport rather than animate freely).
Slider direction is inverted (value=0 is top/air, value=100 is bottom/water, but writing-mode+direction:rtl means visually dragging down increases value, which maps to submerging — however the label reads "SENKEN" at top and "⬆ HOCH" at bottom, suggesting the layout intent is correct but the fall animation is absent (crowns teleport rather than animate freely).