✓ 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 (min=0 at top maps to air, but the vertical slider CSS uses writing-mode/direction such that dragging down increases value toward water, which is actually correct directionally, yet the splash loop relies on frame-countdown with no true animation timeline — crowns jump positions rather than animate smoothly, and fall_animation is absent since motion only updates on slider drag events with no autonomous frame loop.
Slider direction is inverted (min=0 at top maps to air, but the vertical slider CSS uses writing-mode/direction such that dragging down increases value toward water, which is actually correct directionally, yet the splash loop relies on frame-countdown with no true animation timeline — crowns jump positions rather than animate smoothly, and fall_animation is absent since motion only updates on slider drag events with no autonomous frame loop.