- Load Base and React videos from Local or Link (YouTube/direct/Real‑Debrid).
- Press S to sync, D to desync. Use FR to force re‑sync.
- Use Space to play/pause the focused video. Hover to reveal controls.
- Seek with Arrow keys. Hold Shift to target the base video.
- Adjust delay with the − / + buttons. Hold to increase step speed.
- For YouTube, use Q to change quality. Serve over HTTP/HTTPS for best results.
- Drag the React window using the left handle. Resize from the bottom‑right corner.
- Enable debug with 🐛 or add ?debug=true to the URL.