test

graph TB subgraph "クライアント層" Web[Webブラウザ] Mobile[モバイルアプリ] end

subgraph "アプリケーション層"
    LB[Load Balancer]
    API1[API Server 1]
    API2[API Server 2]
    API3[API Server 3]
end

subgraph "データ層"
    Primary[(Primary DB)]
    Replica[(Replica DB)]
    Cache[(Redis Cache)]
end

Web --> LB
Mobile --> LB
LB --> API1
LB --> API2
LB --> API3
API1 --> Primary
API2 --> Primary
API3 --> Primary
API1 --> Cache
API2 --> Cache
API3 --> Cache
Primary --> Replica

style Primary fill:#f9f,stroke:#333,stroke-width:4px
style LB fill:#bbf,stroke:#333,stroke-width:2px