✓ 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 "slide up = crowns into water" but default min=0/max=100 with writing-mode bt-lr means bottom=0/air and top=100/water, which contradicts the prompt requirement of top=air, bottom=water); crown movement is a linear warp with no discrete fall animation — crowns simply translate continuously with no free-fall drop or water-entry event beyond a sparse splash trigger.
Slider direction is inverted (label says "slide up = crowns into water" but default min=0/max=100 with writing-mode bt-lr means bottom=0/air and top=100/water, which contradicts the prompt requirement of top=air, bottom=water); crown movement is a linear warp with no discrete fall animation — crowns simply translate continuously with no free-fall drop or water-entry event beyond a sparse splash trigger.