E-commerce Order Flowchart Template

flowchart TD
    A([Customer opens product page]) --> B[Add to cart]
    B --> C[Place order]
    C --> D{In stock?}
    D -- No --> E[Show out of stock]
    E --> Z([End])
    D -- Yes --> F[Reserve stock]
    F --> G[Choose payment method and pay]
    G --> H{Paid within 30 minutes?}
    H -- No --> I[Cancel order and release stock]
    I --> Z
    H -- Yes --> J[Merchant ships]
    J --> K[Delivery]
    K --> L{Delivery confirmed?}
    L -- Return requested --> M[After-sales handling]
    M --> Z
    L -- Yes --> N[Order complete]
    N --> Z

Draw an e-commerce order flowchart in Mermaid flowchart TD syntax: the customer opens a product page, adds to cart and places the order; check stock (show out of stock and end if none), reserve stock, choose a payment method and pay; if not paid within 30 minutes cancel the order and release stock; otherwise the merchant ships, the parcel is delivered, and the customer either confirms delivery (order complete) or requests a return (after-sales handling). Use rounded nodes for start and end. Output only the mermaid code block.