Worked on enhancing the user interface of the microsoft/vscode repository by implementing new hover states for the Activity Bars, focusing on improving interactivity and visual feedback. Leveraged CSS, TypeScript, and JSON to introduce dedicated theming tokens for hover foreground and background colors, ensuring consistent behavior across both left and top activity bars as well as the sidebar. Refactored default color definitions into a centralized theme file and updated CSS usage to reduce reliance on fallbacks, which improved maintainability. Adjusted linting rules to support new CSS variables, maintaining CI stability, and provided configuration guidance to facilitate adoption of the new theming options.