
The top left navigation does not appear at the top left of the page.

The top left navigation does not appear at the top left of the page.
We are seeing the same behaviour, the navigation menu shows properly in Chrome/Chromium but not on latest Firefox, tested on macOS and GNU/Linux.
On Chrome/Chromium:
vs
On Firefox 141.0.2:
Same here.

This is a pretty wild bug, certainly gives the impression that testing is only being done on Chrome. It would be interesting to see if it shows up on other browsers too.
In the meantime, the UI is there, the CSS just isn’t correct for Firefox. I’ve created a userscript to fix this (link in step 2).
Steps:

