fixes and better mermaid

make-practiceapp-deployready.md

@@ -512,9 +512,16 @@ CMD [ "serve", "-s", "dist", "-l", "8000" ]
 - **Real-time Preview**: Users can see their Mermaid diagram rendered as they type
 - **Error Handling**: Clear error messages for invalid Mermaid syntax
 - **Unique Rendering**: Each render uses a unique ID to prevent caching issues that could cause diagrams to disappear
+- **DOM Cleanup**: Proper cleanup of mermaid-generated DOM elements to prevent accumulation of leftover elements from failed renders
 - **Consistent Styling**: Matches the existing design language of the application
 - **Accessibility**: Proper ARIA labels and semantic HTML structure
 
+**Important Implementation Details**:
+
+- **DOM Element Cleanup**: Added `finally` block in render function to clean up DOM elements that mermaid creates, especially important for failed renders which would otherwise leave orphaned elements
+- **Component Unmount Cleanup**: Added cleanup `useEffect` to remove any lingering mermaid elements when component unmounts
+- **Unique ID Generation**: Uses `useRef` counter to generate unique IDs for each render attempt, preventing mermaid's internal caching issues
+
 This enhancement makes the application more suitable for software architecture exercises that require diagram creation and visualization.
 
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