Yvonne Yeh focused on improving UI reliability in the cultureamp/kaizen-design-system repository by addressing a critical layout issue in the EmptyState panel. She resolved a horizontal overflow bug that affected component behavior on smaller screens, ensuring proper wrapping and fit through targeted SCSS updates. By refining the responsive behavior and visual consistency of the EmptyState component, Yvonne enhanced usability across mobile and narrow viewports. Her work involved applying front end development skills with a strong emphasis on CSS and SCSS, contributing to the overall stability of the design system and reducing the risk of UI regressions in consuming applications.