Salesforce Lightning Design System (SLDS) is a set of guidelines and resources by Salesforce to create cohesive and user-friendly interfaces for applications on their platform. It ensures a seamless user experience, covering design, layout, components, tokens and more.

Salesforce was among the pioneers in introducing the concept of design tokens and promoting this approach in product development. Design System provides a set of design guidelines, components, and resources that enable developers and designers to build applications with a consistent look and feel, enhancing user experience and streamlining development.