✓ 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 (slider.value=0 at bottom maps to crown in air via the `100 - slider.value` inversion, but CSS `slider-vertical` with `direction:rtl` makes the visual top already the max, so the net effect is top=submerged/bottom=air — wrong per spec); mass/volume/density live values are hardcoded in HTML and never updated by JS, only displaced water updates live.
Slider direction is inverted (slider.value=0 at bottom maps to crown in air via the `100 - slider.value` inversion, but CSS `slider-vertical` with `direction:rtl` makes the visual top already the max, so the net effect is top=submerged/bottom=air — wrong per spec); mass/volume/density live values are hardcoded in HTML and never updated by JS, only displaced water updates live.