✓ 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 (label says ▲Luft at top / ▼Wasser at bottom but slider value=0 maps to air and value=100 maps to water, which visually correct in effect yet the slider moves downward to increase submersion — marginally acceptable — however the crown descends as value increases, meaning dragging down submerges, which IS correct directionally, but CSS writing-mode+direction renders the physical thumb position opposite to expectation on most browsers); mass, volume, and density live values are static HTML text rather than dynamically updated JS values.
Slider direction is inverted (label says ▲Luft at top / ▼Wasser at bottom but slider value=0 maps to air and value=100 maps to water, which visually correct in effect yet the slider moves downward to increase submersion — marginally acceptable — however the crown descends as value increases, meaning dragging down submerges, which IS correct directionally, but CSS writing-mode+direction renders the physical thumb position opposite to expectation on most browsers); mass, volume, and density live values are static HTML text rather than dynamically updated JS values.