Worked on the nhsuk/nhsuk-frontend repository to enhance the SCSS mixin for nhsuk-panel by introducing an optional border color parameter. This update allowed developers to apply conditional styling and omit the border color when not needed, reducing repetitive code and aligning with design-system standards. The implementation focused on improving flexibility in front end development using CSS, Sass, and SCSS, while also updating project documentation and the changelog to reflect the new feature. No major bugs were addressed during this period, with efforts concentrated on streamlining styling workflows and supporting more efficient, maintainable theming for the design system.