I use a password manager for all passwords, and it seems mighty confused by the pi-hole login page.
I managed to finally configure the password manager to only enter the password, but not having a user name is very different from any other login page out there.
My suggestion/feature request is to add a user name to the page. We don’t even need to create a whole lot of authentication logic to handle the user name – the server code could simply ignore the user, or expect a hard-coded name of “admin”.
Of course, it would be preferable for the owner to be able to override the admin user name, but looking at how routers usually works, the hard-coded “admin” seems to be the norm.
As for coding, I have already customized my own copy, but didn’t want to submit a Pull Request before knowing if there’s consensus that this is a Good Idea
Screenshot of my local customization: