✓ 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 (comment says "slide up to lower crowns into water" but slider value 0=top=air and 100=bottom=water is actually correct for a vertical slider DOM-wise, yet the crown Y calculation `5 - depth*25` means higher slider value pushes crowns upward off-screen rather than downward into water); displacement ratio logic uses hardcoded crown height of 3 ASCII rows rather than actual volume ratios, making physics approximate and inconsistent.
Slider direction is inverted (comment says "slide up to lower crowns into water" but slider value 0=top=air and 100=bottom=water is actually correct for a vertical slider DOM-wise, yet the crown Y calculation `5 - depth*25` means higher slider value pushes crowns upward off-screen rather than downward into water); displacement ratio logic uses hardcoded crown height of 3 ASCII rows rather than actual volume ratios, making physics approximate and inconsistent.