2018-06-21, 08:00 PM
2018-06-21, 08:15 PM
Apart from the login page, which currently (1.8.15) has a bug preventing customization, you can style the ACP by creating a style.php file in your ACP theme and extending the DefaultPage class. There are quite a few themes in the Extend section you may watch out for inspiration and learning how to do your own ACP theme without editing the core.