Developed a centralized NHS color system within the nhsuk-frontend repository, establishing a single source of truth for brand colors to ensure consistent theming across frontend applications. Leveraged Sass to implement a comprehensive color palette and introduced the nhsuk-colour() helper, enabling maintainable and scalable color management. Emitted CSS custom properties from the Sass palette, allowing downstream applications to easily consume standardized color tokens. This approach improved design consistency, reduced theming defects, and streamlined design-to-code handoffs for multiple teams. The work demonstrated proficiency in CSS, JavaScript, and frontend development, delivering foundational infrastructure for UI theming and cross-project collaboration.