✓ 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 (hint labels say ▲ Air / ▼ Water but value=0 maps to crowns in air which is correct semantically, yet the vertical slider's physical top produces value=100/water — the writing-mode/direction CSS makes the top of the track the HIGH value, meaning dragging up submerges the crowns, contradicting the "▲ Luft ▼ Wasser" label); no discrete fall animation (crowns move continuously with slider rather than a separate drop sequence); all physics values are accurate and the heureka overlay with sparkles is a strong touch.
Slider direction is inverted (hint labels say ▲ Air / ▼ Water but value=0 maps to crowns in air which is correct semantically, yet the vertical slider's physical top produces value=100/water — the writing-mode/direction CSS makes the top of the track the HIGH value, meaning dragging up submerges the crowns, contradicting the "▲ Luft ▼ Wasser" label); no discrete fall animation (crowns move continuously with slider rather than a separate drop sequence); all physics values are accurate and the heureka overlay with sparkles is a strong touch.