The CMS Design System is an open-source project that provides design and front-end development resources for creating accessible, responsive, and consistent websites, particularly for government agencies and healthcare organizations. It offers a set of reusable CSS, JS, and React components, utility classes, and a grid framework to help teams quickly prototype and build production-ready websites. The project is designed for developers, designers, and organizations looking to create Section 508 compliant websites with a consistent user experience.