Ubuntu, like other Linux distributions uses the GNOME Display Manager (GDM) as its, well, display manager, though most of us tend to think of or refer to it as the login screen.
To customise the Ubuntu login screen, such as setting a different theme or icon set, changing the login screen background image or colour, or getting night light to apply when viewing it, you can use a 3rd-party tool called GDM Settings.
Appearance options galore
The app is written in Python and uses libadwaita for its UI, so it looks great on the modern Ubuntu desktop and adapts gracefully when resizing the window or running on width-constrained displays.
GDM Settings allows you to:
- Set the login screen background image or color
- Modify the login screen theme, icons, and cursor
- Alter font, font sizes, and the scaling factor
- Display the battery percentage on the login screen
- Customize the top bar text and background colors
- Define mouse and touchpad behaviors
- Enable or disable on-screen options like the user list
- Adjust power settings such as dimming the screen or setting a screen timeout
- Turn on Night Light support
And a whole lot more.
You can also hide elements of the default login screen
The “big” thing:
GDM Settings is not an official GNOME tool. Use it cautiously, at your own risk. Some tweaks/options available in the app may not be adjusting intentionally configurable values or might alter hardcoded settings ad-hoc.
There have been reports of this tool causing issues, for example, changing the login screen color causing GDM to fail to load after, presenting with the annoying “Oh no! Something has gone wrong” error screen.
Again: use this at your own risk.
Getting GDM Settings
You can install GDM Settings from Flathub but the sandboxed nature of Flatpak means some features of the tool are not available/may not work.