Yusuaois developed cross-platform volume management improvements and persistence for the Kazumi repository, focusing on enhancing user experience and code maintainability. Using Flutter and Dart, Yusuaois implemented persistent volume settings across sessions, introduced platform-aware initialization, and set sensible defaults such as 100% volume on desktop. The solution included asynchronous startup fetching to ensure correct volume restoration and the removal of redundant state variables for cleaner code. Additionally, Yusuaois addressed a UI flow issue by ensuring playback pauses before the player hides on non-macOS platforms, reducing glitches and improving reliability for both mobile and desktop users within a single development cycle.