Where is the xfce4 login screen directory?

I want to little customize login screen in Xubuntu. I found default login window background image directory, /usr/share/xfce4/backdrops , but I can’t find login popup window scripts, e.g. with color HEX codes. Just now color is white, but I need to change it to #000000, i.e. black. Also found scripts with color descriptions for themes in /usr/share/themes/ but, you know, that is not what’s needed.

Xubuntu uses LightDM with the GTK greeter for the login screen. To change the login popup window color (e.g., background, text, etc.), you need to modify the LightDM GTK greeter theme, not just XFCE or wallpaper settings.


Steps to change login popup window color:

  1. Edit the LightDM GTK greeter config:
sudo nano /etc/lightdm/lightdm-gtk-greeter.conf

Add or edit this line under [greeter]:

theme-name=MyCustomTheme
  1. Customize the theme:
    Find the theme folder (example: /usr/share/themes/MyCustomTheme/gtk-3.0/gtk.css)Or copy and modify an existing one:
sudo cp -r /usr/share/themes/Greybird /usr/share/themes/MyCustomTheme
  1. Edit the CSS file to change popup colors:
    Open:
sudo nano /usr/share/themes/MyCustomTheme/gtk-3.0/gtk.css

Add or modify the background color for login popup (you’ll have to experiment, but this works for most greeters):

.lightdm-gtk-greeter {
    background-color: #000000;
    color: #FFFFFF;
}
  1. Test changes:
    Reboot or run:
lightdm --test-mode

Tip:

You can install lightdm-gtk-greeter-settings for a GUI tool:

sudo apt install lightdm-gtk-greeter-settings

It lets you adjust theme, background, fonts, and colors visually.


Let me know if you want a dark theme ready to drop in.