The user’s login screen and desktop can be configured here.

Login screen

The headline is displayed below the logo.

A corresponding logo can be specified here via an absolute path.
The logo can be uploaded to the system in “System” under “Settings” -> “Image upload”.
After uploading, the exact url is displayed. This can be used here.

A background image can be set in the same way as a logo.

The background color can be set from a color selection dialog.

Desktop

The color scheme can be set between light and dark.
The highlight color can be set via a color selection dialog.
A background image can be set (upload see above)
If no background image is used, a background color can be set.
The text style (text under the icon in the desktop) can be set via CSS styles, e.g. font-size:10px