graph LR
    subgraph HomeNetwork [Home Network]
        Alice[Alice ShadowGhost]
        HomeRouter[Home Router]
        Alice --> HomeRouter
    end
    
    subgraph OfficeNetwork [Office Network]
        Bob[Bob ShadowGhost]
        OfficeRouter[Office Router]
        Bob --> OfficeRouter
    end
    
    subgraph InternetServices [Internet Services]
        STUNServer[STUN Server]
        RelayServer[TURN Relay]
    end
    
    subgraph ManualProcess [Manual Contact Exchange]
        SGLinkGen[Alice generates SG link]
        SGLinkShare[Share link via external channel]
        SGLinkAdd[Bob adds SG link]
    end
    
    HomeRouter -.->|Get external IP| STUNServer
    OfficeRouter -.->|Get external IP| STUNServer
    
    Alice --> SGLinkGen
    SGLinkGen --> SGLinkShare
    SGLinkShare --> SGLinkAdd
    SGLinkAdd --> Bob
    
    HomeRouter <==>|Direct P2P| OfficeRouter
    HomeRouter -.->|Fallback| RelayServer
    RelayServer -.-> OfficeRouter
    
    classDef user fill:#4CAF50,stroke:#2E7D32,color:#fff
    classDef router fill:#9C27B0,stroke:#6A1B9A,color:#fff
    classDef server fill:#FF9800,stroke:#F57C00,color:#fff
    classDef manual fill:#FF5722,stroke:#D84315,color:#fff
    
    class Alice,Bob user
    class HomeRouter,OfficeRouter router
    class STUNServer,RelayServer server
    class SGLinkGen,SGLinkShare,SGLinkAdd manual