Developed and integrated built-in Undertale and Deltarune themes for the sst/opencode repository, focusing on character-specific color schemes and comprehensive UI color definitions to enhance user customization and interface consistency. The work centered on designing a scalable theming framework using JSON, enabling rapid onboarding of future themes and supporting ongoing UI/UX improvements. All changes were implemented through well-documented commits linked to a dedicated feature issue, ensuring traceability and maintainability. The technical approach emphasized theme development and UI/UX design, establishing a robust color system that strengthens brand alignment and lays the groundwork for future enhancements without addressing bug fixes during this period.