From the blog post: "Primer isn’t another large front-end framework, though. It’s rather limited in functionality and isn’t intended to replace something like Bootstrap. It will always be GitHub’s internal toolkit first, designed to help build GitHubby things. That said, we love to share."
That was kinda my take away, too. It's pretty minimalist overall.
That was kinda my take away, too. It's pretty minimalist overall.