✓ 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 starts crowns near top in air but slider thumb at bottom visually due to bt-lr writing-mode quirks, and the crown Y simply adds depth offset rather than starting in air and moving down correctly); density of the gilded crown (9.2 g/cm³) is plausibly silver-range but the water-level rise calculation is dimensionally inconsistent (pixels mixed with cm³ without a proper scale), and displaced volume updates linearly with slider rather than accounting for partial submersion geometry.
Slider direction is inverted (value=0 starts crowns near top in air but slider thumb at bottom visually due to bt-lr writing-mode quirks, and the crown Y simply adds depth offset rather than starting in air and moving down correctly); density of the gilded crown (9.2 g/cm³) is plausibly silver-range but the water-level rise calculation is dimensionally inconsistent (pixels mixed with cm³ without a proper scale), and displaced volume updates linearly with slider rather than accounting for partial submersion geometry.