Sushant Shrestha focused on streamlining theme configuration across major Flutter repositories, including flutter/website, flutter/samples, and flutter/flutter. He removed redundant explicit use of the useMaterial3: true setting in Dart code, aligning theme definitions with the default Material 3 behavior in recent Flutter versions. This cleanup reduced duplication and configuration drift, improving maintainability and consistency of Material Design components without altering visuals or functionality. By leveraging his expertise in Dart, Flutter, and UI development, Sushant enabled simpler theme updates and faster UI iterations, contributing to cleaner codebases and more efficient collaboration for design and development teams.