MERMAID CLASS DIAGRAM SYNTAX RULES:

DECLARATION:
- Start with: classDiagram

CLASS DEFINITION:
- class ClassName {
-   +attribute: type
-   -method(): returnType
- }

VISIBILITY:
- + = Public
- - = Private
- # = Protected
- ~ = Package/Internal

RELATIONSHIPS:
- <|-- = Inheritance
- *-- = Composition
- o-- = Aggregation
- --> = Association
- ..> = Dependency
- ..|> = Realization

METHOD SYNTAX:
- method(param: type): returnType
- +publicMethod(): void
- -privateMethod(param: string): int

COMMON ISSUES:
- Missing visibility modifiers
- Invalid class names with spaces or hyphens
- Malformed method signatures
- Incorrect relationship arrows

FIX REQUIREMENTS:
1. Use valid class names (PascalCase recommended)
2. Include visibility modifiers for all members
3. Use proper relationship arrow syntax
4. Follow method signature format exactly