Worked on the mdn/translated-content repository to improve the accuracy of French-language documentation for CSS custom properties. Focused on enhancing translation quality by identifying and correcting a terminology error in the Syntax section of the CSS var() documentation, replacing the word 'recours' with 'substitution' in two instances. This change aligned the French translation more closely with the English original, reducing ambiguity for French-speaking developers. Utilized Markdown for documentation updates and applied translation skills to ensure consistency and clarity. The work addressed a specific bug, contributing to a better developer experience and more reliable localization for users referencing CSS documentation.