I found that GitHub has published its own dark mode and that’s pretty cool.
At GitHub Settings - Appearance
Official Dark Mode
Really wonderful, supports more colors and components.
GitHub Dark Mode Extension
More colorful but doesn't support some special components.
I’m currently enjoying using the official dark mode.
This means, GitHub Dark Mode Extension is useless now…
So, GitHub Dark Mode Extension will add more features to improve your experience like blur effects, smooth transitions and more.