✓ 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 (label says top=Luft/air, bottom=Wasser/water, but the HTML range input with writing-mode+direction tricks maps value=0 at top visually — needs verification; the submerged fraction computation multiplies by `t` twice via `submergedFrac * t` giving incorrect partial submersion physics, though overall displacement direction and magnitude are directionally correct; buoyancy unit conversion is doubly scaled (9.81 × 0.0981 is wrong).
Slider direction is inverted (label says top=Luft/air, bottom=Wasser/water, but the HTML range input with writing-mode+direction tricks maps value=0 at top visually — needs verification; the submerged fraction computation multiplies by `t` twice via `submergedFrac * t` giving incorrect partial submersion physics, though overall displacement direction and magnitude are directionally correct; buoyancy unit conversion is doubly scaled (9.81 × 0.0981 is wrong).