First confirmed with Firefox on Ubuntu, same on mobile (Safari) too.
P.S. If you are from GitHub, please note we appreciate all your hard work! Posted only to have a discussion.
GitHub navbar is broken for repo URLs when logged out
1–2 of 2 posts
Re: GitHub navbar is broken for repo URLs when logged out
#2The background-color property on class .header-logged-out seems to be the culprit. Removing this property fixes the problem.
In the meantime, switching to dark mode in the browser makes the navbar visible again.