graph TD
    A[Client] --> B[Load Balancer]
    B --> C[Server01]
    B --> D[Server02]

flowchart TB
    subgraph Client["客户端层"]
        Web[Web App]
        Mobile[Mobile App]
        Desktop[Desktop App]
    end
    subgraph Gateway["API 网关层"]
        Kong[Kong Gateway]
        Auth[Auth Service]
        RateLimit[Rate Limiter]
    end
    subgraph Services["微服务层"]
        direction TB
        subgraph Core["核心服务"]
            UserSvc[User Service]
            OrderSvc[Order Service]
            ProductSvc[Product Service]
            PaymentSvc[Payment Service]
        end
        subgraph Support["支撑服务"]
            NotifySvc[Notification Service]
            SearchSvc[Search Service]
            AnalyticsSvc[Analytics Service]
        end
    end
    subgraph Data["数据层"]
        PostgreSQL[(PostgreSQL)]
        MongoDB[(MongoDB)]
        Redis[(Redis Cache)]
        Elasticsearch[(Elasticsearch)]
    end
    subgraph MQ["消息队列"]
        Kafka[Apache Kafka]
    end
    Web & Mobile & Desktop --> Kong
    Kong --> Auth
    Kong --> RateLimit
    Auth --> UserSvc
    Kong --> UserSvc & OrderSvc & ProductSvc & PaymentSvc
    
    UserSvc --> PostgreSQL
    OrderSvc --> PostgreSQL
    ProductSvc --> MongoDB
    PaymentSvc --> PostgreSQL
    
    OrderSvc & PaymentSvc --> Kafka
    Kafka --> NotifySvc & AnalyticsSvc
    
    SearchSvc --> Elasticsearch
    ProductSvc --> Redis
    UserSvc --> Redis
    style Kong fill:#e1f5fe
    style Kafka fill:#fff3e0
    style PostgreSQL fill:#e8f5e9
    style Redis fill:#ffebee

$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$

\begin{aligned}
\nabla \times \vec{\mathbf{E}} &= -\frac{\partial \vec{\mathbf{B}}}{\partial t} \\
\nabla \times \vec{\mathbf{B}} &= \mu_0 \vec{\mathbf{J}} + \mu_0 \varepsilon_0 \frac{\partial \vec{\mathbf{E}}}{\partial t} \\[1em]
\hat{f}(\xi) &= \int_{-\infty}^{\infty} f(x) e^{-2\pi i x \xi} dx \\[1em]
\mathbf{A} &= \begin{pmatrix} 
\frac{\partial^2 u}{\partial x^2} & \frac{\partial^2 u}{\partial x \partial y} & \cdots \\
\frac{\partial^2 u}{\partial y \partial x} & \frac{\partial^2 u}{\partial y^2} & \cdots \\
\vdots & \vdots & \ddots
\end{pmatrix} \\[1em]
\sum_{n=1}^{\infty} \frac{(-1)^{n+1}}{n} &= \ln(2) \quad \text{and} \quad \prod_{p \text{ prime}} \frac{1}{1-p^{-s}} = \zeta(s)
\end{aligned}