✓ 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 (slider value 0=top=air is correct semantically but the vertical CSS uses writing-mode+direction:rtl which flips it so dragging toward the bottom moves crowns up, not down into water); physics, live values, splash, rising water, and Heureka overlay are all solidly implemented.
Slider direction is inverted (slider value 0=top=air is correct semantically but the vertical CSS uses writing-mode+direction:rtl which flips it so dragging toward the bottom moves crowns up, not down into water); physics, live values, splash, rising water, and Heureka overlay are all solidly implemented.