%%%{init: {'themeVariables': {'sequenceDiagramTheme': 'default'}}}%%%

sequenceDiagram
    participant User
    participant PaymentGateway
    participant Database

    User->>PaymentGateway: Initiate Payment
    alt Successful Payment
        PaymentGateway->>Database: Commit Transaction
        Database-->>PaymentGateway: Confirm Commit
        PaymentGateway-->>User: Payment Success
    else External Failure
        PaymentGateway-->>User: Payment Failure
    else DB Failure
        PaymentGateway->>Database: Rollback Transaction
        Database-->>PaymentGateway: Confirm Rollback
        PaymentGateway-->>User: Payment Rollback
    end