✓ 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 (writing-mode:vertical-lr + direction:rtl maps value=0 to the bottom visually, so dragging down raises the value and submerges crowns — opposite of the required top=air/bottom=water convention); no autonomous fall animation (crowns only move when slider is dragged); physics, live values, splash/ripple, and Heureka overlay are all well-implemented.
Slider direction is inverted (writing-mode:vertical-lr + direction:rtl maps value=0 to the bottom visually, so dragging down raises the value and submerges crowns — opposite of the required top=air/bottom=water convention); no autonomous fall animation (crowns only move when slider is dragged); physics, live values, splash/ripple, and Heureka overlay are all well-implemented.