Worked on maintaining and improving the CSS Masonry test suite within the mozilla/gecko-dev repository, focusing on test reliability and clarity rather than feature development. Over two months, addressed issues in web-platform-tests by aligning test file naming conventions and updating references to ensure accurate execution in continuous integration environments. Expanded test coverage by adding new cases for item-tolerance variations and refining existing tests to reduce flakiness and improve maintainability. Utilized skills in CSS, HTML, and testing to ensure that the Masonry layout behavior is accurately captured, supporting future development and enhancing the overall stability of the test infrastructure.