Packing Chromatic Number
Graph Interaction:
1. **Click on SVG**: Add Node
2. **Drag Node to Node**: Add Edge
3. **Right-click Node**: Delete Node
4. **Ctrl + Drag Node**: Move Node
5. **Right-Click Drag**: Delete Region
6. **Ctrl + Z**: Undo last action
7. **Scroll Wheel**: Zoom
8. **Shift + Drag**: Pan Canvas
System ready.