✓ 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 starts crowns in air but slider moves upward toward 100 to submerge, yet HTML range sliders render min at bottom when vertical via writing-mode, so top=100=submerged rather than top=air=0); no smooth fall/drop animation — crowns teleport positionally based on slider with no gravity/tween; splash only triggers for the narrow 0–15% band and won't re-trigger on reset without page reload due to the splashActive flag never resetting.
Slider direction is inverted (value=0 starts crowns in air but slider moves upward toward 100 to submerge, yet HTML range sliders render min at bottom when vertical via writing-mode, so top=100=submerged rather than top=air=0); no smooth fall/drop animation — crowns teleport positionally based on slider with no gravity/tween; splash only triggers for the narrow 0–15% band and won't re-trigger on reset without page reload due to the splashActive flag never resetting.