✓ 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 is inverted — value=0 at top maps to crowns in air (accidentally correct visually via easing starting at t=0), but the hint text says "Ziehen zum Eintauchen" (pull to submerge) implying upward drag = submerge, which inverts the expected UX convention; the `-webkit-appearance: slider-vertical` with `direction: rtl` means slider thumb at top = value 100, yet the code uses value=0 at start (crowns in air), so the direction mapping is backwards.
Slider is inverted — value=0 at top maps to crowns in air (accidentally correct visually via easing starting at t=0), but the hint text says "Ziehen zum Eintauchen" (pull to submerge) implying upward drag = submerge, which inverts the expected UX convention; the `-webkit-appearance: slider-vertical` with `direction: rtl` means slider thumb at top = value 100, yet the code uses value=0 at start (crowns in air), so the direction mapping is backwards.