Over a two-month period, contributed front-end features to major open-source projects using TypeScript, Vue.js, and CSS. In the vuetifyjs/vuetify repository, developed enhancements to the theme configuration system by introducing options for unique stylesheet IDs and scoped styles, enabling more granular theme management and supporting microfrontend architectures. This work improved style isolation and laid the foundation for scalable theming in complex deployments. In the vitest-dev/vitest repository, implemented a Slow Test Filter in the UI, allowing teams to quickly identify and manage tests exceeding duration thresholds. Both features focused on modularity, maintainability, and improved developer experience without introducing bug fixes.