Yes. To do so you can go to the project's directory (Project → Show project directory in Explorer) and modify /theme/login.html to your liking.
you can use deeplink module or edit login.html page
Other than options explained above, I will give the below option, as you expect registration.
- You can enable anonymous users in your project
- Design your login and registration page within modeler. Provide the permissions for anonymous user only for these two pages
- Make sure you dont enable anonymous users for other entities and/or pages