Matthew Claffey developed a centralized NHS color system for the nhsuk-frontend repository, establishing a single source of truth for brand colors to support consistent theming across frontend applications. He implemented a Sass-based color palette and created the nhsuk-colour() helper, which outputs CSS custom properties so downstream applications can easily consume standardized color tokens. Using JavaScript, SCSS, and CSS, Matthew’s work improved design consistency and reduced theming defects by ensuring all projects reference the same palette. This foundation streamlines UI theming and accelerates design-to-code handoffs, reflecting a focused and foundational contribution to frontend infrastructure within a short timeframe.