✓ 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 at top means crowns in air, but range-vertical with writing-mode:vertical-lr + direction:rtl makes top physically render as max value, so user dragging up submits crowns — semantics are reversed from the natural expectation); otherwise a highly polished, physically accurate, feature-complete demo.
Slider direction is inverted (value=0 at top means crowns in air, but range-vertical with writing-mode:vertical-lr + direction:rtl makes top physically render as max value, so user dragging up submits crowns — semantics are reversed from the natural expectation); otherwise a highly polished, physically accurate, feature-complete demo.