Improve the login / passwort reset / registration template

Problem/Motivation

Improve the login / passwort reset / registration template.
Currently it's full width, should be more visually appealing, e.g. having a max-width container around the form.

I think this is specific to these pages.

I just saw that the AdminLTE demo already provides templates for login / registration / password reset:
https://adminlte.io/themes/v4/examples/login.html

Maybe AI is able to adopt them to Drupal?

(Still I don't think we have to use them by hard, but would be consistent of course)

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes