Primer CSS
The CSS design system that powers GitHub
Our goal is to create a system that enables us to build consistent user experiences with ease, yet with enough flexibility to support the broad spectrum of GitHub websites. This goal is embedded in our design and code decisions. Our approach to CSS is influenced by Object-Oriented CSS principles, functional CSS, and BEM architecture. Styles can be mixed and matched to achieve many different layouts, independent of their location. These styles fall into three categories. Single-purpose...