Customise password-protected pages

Hello,

I want to customise the password protected pages because as you can see in the example I created, it doesn’t have any style. I’m looking for it but I can’t find the line of code that allows me to do it. I prefer to avoid extra plugins to edit this.

I’m using Elementor (free) so if there is some kind of “combination” between plugin and code, it will also be useful for me.

Thanks in advance.

The page I need help with: [log in to see the link]