MERMAID FLOWCHART SYNTAX RULES:

DECLARATION:
- Start with: flowchart TD (or LR, BT, RL for direction)
- Alternative: graph TD (legacy syntax)

NODE SHAPES:
- [text] = Rectangle (default process)
- ([text]) = Stadium/Pill (start/end points)
- {text} = Rhombus/Diamond (decision points)
- [(text)] = Database (data storage)
- [[text]] = Subroutine (function calls)
- ((text)) = Circle (connectors)
- [/text/] = Parallelogram (input/output)

ARROWS:
- --> = Standard arrow
- -.-> = Dotted arrow
- ==> = Thick arrow
- --x = Arrow with cross
- -->|text| = Labeled arrow

SUBGRAPHS:
- subgraph title
-   content
- end

STYLING:
- style NodeID fill:#color,stroke:#border,color:#text

COMMON ISSUES:
- Invalid node IDs starting with numbers or containing hyphens
- Unquoted text with spaces or special characters
- Missing arrow labels for decision branches
- Unclosed subgraph blocks

FIX REQUIREMENTS:
1. Use valid node identifiers (letters, numbers, underscores)
2. Quote text with spaces: ["text with spaces"]
3. Label all decision branches clearly
4. Close all subgraph blocks with 'end'