Worked on the mozilla/gecko-dev repository to enhance the reliability of CSS animation tests by updating test files to reflect the latest CSS animation specifications. Focused on renaming the CSS property 'animation-trigger-type' to 'animation-trigger-behavior' throughout the test suite, this change improved test accuracy and reduced the likelihood of false results. Utilized skills in CSS Animations, front end development, and testing, with work primarily involving HTML and JavaScript. Demonstrated careful change management by making traceable, well-documented commits, which streamlined code reviews and future maintenance. The update addressed a specific bug, contributing to more consistent and standards-compliant test outcomes.