✓ 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 (value=0 puts crowns above container, increasing drags them down, but the HTML range slider's native vertical orientation means dragging UP increases value = crowns go deeper, which is backwards); ASCII-art rendering is functional but crowns don't visually move smoothly relative to the water line due to flawed Y-position math (goldY decreases as depth increases, moving crowns UP rather than down into water).
Slider direction is inverted (value=0 puts crowns above container, increasing drags them down, but the HTML range slider's native vertical orientation means dragging UP increases value = crowns go deeper, which is backwards); ASCII-art rendering is functional but crowns don't visually move smoothly relative to the water line due to flawed Y-position math (goldY decreases as depth increases, moving crowns UP rather than down into water).