✓ 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 (bt-lr writing-mode means dragging up increases value, but semantically top=air is not enforced by layout), and crown movement is a simple positional offset with no true fall animation — crowns jump/slide without easing or gravity feel.
Slider direction is inverted (bt-lr writing-mode means dragging up increases value, but semantically top=air is not enforced by layout), and crown movement is a simple positional offset with no true fall animation — crowns jump/slide without easing or gravity feel.