I have some ideas i would like to discuss.
to rename "change address" to "logout" and put it in the top right corner.
put the login form an a separate html without distraction.
Why? "Logout" term is usually used in a web app, but hides the fact what it actually does.
This would remove some javascript.
Mockups:

------- login page ------

also look at https://burner.kiwi/, i love it for it's simplicity.