✓ 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 (label says top=Luft/air but slider HTML min=0 at top maps to crown in air yet the writing-mode:vertical-lr with direction:rtl rendering is browser-dependent and visually ambiguous); mass, volume, and density values are static rather than live; crown animation is a simple linear translateY with no fall/drop physics, no true falling animation arc.
Slider direction is inverted (label says top=Luft/air but slider HTML min=0 at top maps to crown in air yet the writing-mode:vertical-lr with direction:rtl rendering is browser-dependent and visually ambiguous); mass, volume, and density values are static rather than live; crown animation is a simple linear translateY with no fall/drop physics, no true falling animation arc.