Worked on stabilizing data visualization in the PyPSA/pypsa-eur repository by addressing plotting crashes caused by incomplete technology color definitions. Developed a robust color lookup and validation mechanism in Python, introducing the _get_tech_colors() function and warning logs to ensure safe handling of missing color mappings. Enhanced maintainability by adding regression tests in YAML and Python, which verify technology color handling and provide safe fallbacks. The work included resolving issues related to missing 'heat dsm' color mapping, resulting in more reliable dashboards for stakeholders. The approach emphasized clean, refactor-friendly code and minimal user disruption while improving long-term reliability.