In this guide, we'll be changing the default classic admin theme to the very popular Reno theme.
Install the Reno module.
/**
* Default admin theme
*
* Module name of default admin theme for guest and users that haven't already selected one
*
* Core options include: **AdminThemeDefault** or **AdminThemeReno**.
* Additional options will depend on what other 3rd party AdminTheme modules you have installed.
*
* @var string
*
*/
$config->defaultAdminTheme = 'AdminThemeReno';
Refresh your page, and bingo! Enjoy your new admin theme!