Primer CSS
Primer CSS is a free, open-source design system. Primer is GitHub's design system. This is the CSS implementation. It has 13,027 GitHub stars and is released under the MIT license. A live demo is linked from this page. Start a project with npx degit primer/css or clone the repository.
Get started
Copy the files into a new folder with degit (no git history), or clone the repository with git.
npx degit primer/css my-ui
cd my-uigit clone --depth 1 https://github.com/primer/css.git my-uiSources: GitHub docs on template repositories, degit.
About Primer CSS
This project is in KTLO mode! Use existing utility classes from this project where needed. For more complete patterns that include styling and markup, please use primer/react or, if necessary, primer/view_components.
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What is Primer CSS?
Primer CSS is a free, open-source design system. Primer is GitHub's design system. This is the CSS implementation. It has 13,027 GitHub stars and is released under the MIT license. A live demo is linked from this page. Start a project with npx degit primer/css or clone the repository.
How do I use Primer CSS?
Copy the files into a new folder with npx degit primer/css my-ui (no git history), or fork the repository on GitHub. Then follow the README for the install and dev commands.
Can I use Primer CSS for commercial projects?
Yes. Primer CSS is released under the MIT license, a permissive license that allows commercial use as long as you keep the copyright and license notice. Third-party assets bundled with it (images, fonts, icons) may have their own terms.
Is Primer CSS maintained?
The repository's most recent commit was on Oct 7, 2026. Its latest release is v22.3.0. appsgit only lists templates from repositories with a commit in the last six months.