✓ 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 (min=0 at top means air, but crown1/2 translateY offset logic moves crowns downward off-screen rather than into the visible water container, and the label says "slide down to submerge" which means top=air is correct conceptually but the crown transform moves them away from the water container rather than into it); mass/volume/density values are static (not live/updating); fall animation is absent (crowns teleport via transform offset).
Slider direction is inverted (min=0 at top means air, but crown1/2 translateY offset logic moves crowns downward off-screen rather than into the visible water container, and the label says "slide down to submerge" which means top=air is correct conceptually but the crown transform moves them away from the water container rather than into it); mass/volume/density values are static (not live/updating); fall animation is absent (crowns teleport via transform offset).