✓ 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 ⬆Luft / ⬇Wasser but the vertical range input with writing-mode:vertical-lr + direction:rtl maps value=0 to the bottom and value=100 to the top, so dragging up increases submersion, opposite of the intended top=air/bottom=water convention); otherwise physics, visuals, and feature completeness are strong.
Slider direction is inverted (label says ⬆Luft / ⬇Wasser but the vertical range input with writing-mode:vertical-lr + direction:rtl maps value=0 to the bottom and value=100 to the top, so dragging up increases submersion, opposite of the intended top=air/bottom=water convention); otherwise physics, visuals, and feature completeness are strong.