Worked on the web-platform-tests/wpt repository to address a bug in the LayoutShift API, ensuring attribution data is now reported in CSS pixels rather than physical pixels. This change required careful updates to both the API implementation and its associated tests, with a focus on accurately representing integer and fractional pixel values for consistency with other layout APIs. Utilized JavaScript and HTML to improve test coverage and reliability, directly impacting the accuracy of Cumulative Layout Shift (CLS) measurements. The work demonstrated attention to detail in web development and testing, contributing to more consistent and reliable performance metrics across the platform.