Worked on stabilizing Mermaid diagram rendering in the Joplin desktop client, addressing a bug where search highlights corrupted Mermaid source code and caused visual artifacts in diagrams. Applied a targeted JavaScript fix that isolated highlighting to specific editable blocks, ensuring that diagram source remained unaffected during searches. This change improved the reliability of diagram rendering, particularly for users working with diagram-heavy notes and documents. The work demonstrated a strong understanding of front end development and rendering pipelines, and was delivered through a contribution to the laurent22/joplin repository. The solution enhanced document fidelity and user confidence by preventing rendering inconsistencies and failures.