Summary & Key Takeaways ​

• GitHub fully migrated github.com away from CSS-in-JS.
• The migration aimed to improve site performance.
• Involves shipping more traditional CSS.
• Represents a significant architectural decision for a large platform.

Our Commentary ​

This is a bold move from GitHub. We've seen the pendulum swing on CSS-in-JS for years, and a major player like GitHub publicly moving away from it for performance reasons is a huge signal. It makes me genuinely wonder about the long-term viability of some of these solutions.