✓ 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 (min=0 at top maps to air, but the vertical CSS with direction:rtl and slider-vertical appearance means drag-down increases value correctly in some browsers yet the label says "Luft ▲ top / Wasser ▼ bottom" while value=0 means air — directionally ambiguous and browser-dependent; more critically the slider value only updates sliderVal without correcting for the rtl/vertical rendering, so behaviour is inconsistent cross-browser.
Slider direction is inverted (min=0 at top maps to air, but the vertical CSS with direction:rtl and slider-vertical appearance means drag-down increases value correctly in some browsers yet the label says "Luft ▲ top / Wasser ▼ bottom" while value=0 means air — directionally ambiguous and browser-dependent; more critically the slider value only updates sliderVal without correcting for the rtl/vertical rendering, so behaviour is inconsistent cross-browser.