Changing the look and feel
Keycloak provides an amazingly simple experience for changing themes and allows you to change most – if not all – of its UI, from the end user-facing pages to the administration console itself.
In this topic, you will learn about the basics of theming by going through examples of how to change the look and feel of the login page. By understanding these basics, you should then be able to apply the same concepts to any other UI you want to customize.
This is probably one of the most documented features of Keycloak. Consider looking at the documentation available at https://www.keycloak.org/docs/latest/server_development/#_themes.