Worked on improving rendering stability for the ThoughtChain component within the ant-design/x repository, focusing on front end development using React, JavaScript, and TypeScript. Addressed a bug where duplicate className values in clsx and undefined contentOpen states could impact component visibility, ensuring more predictable UI behavior. Enhanced the test suite to reliably detect duplicate className tokens by inspecting the raw class attribute, increasing regression protection against UI inconsistencies. Resolved CSSMotion edge cases related to uncontrolled expandedKeys, reducing flicker and improving consistency. Maintained clear communication through detailed commit messages and demonstrated strong attention to code quality and collaborative development practices throughout the process.