Platform: Debian 11 (Bullseye) with Xfce.

I've created ~/.themes/Adwaita-Rosuav/gtk-3.0/gtk.css to try to create a variant of the Adwaita theme. It correctly shows up in the "Appearance" settings list, and can be selected. Trivial changes like headerbar {background: red;} work correctly, so that's a good start.

What CSS directives apply to a window that has marked itself as "urgent"? How do you change the title bar, and even better, the way that it appears in the Running Windows panel - is there a CSS class for urgent windows?

My CSS file starts with @import url("resource:///org/gtk/libgtk/theme/Adwaita/gtk-contained.css"); which appears to correspond to the files in https://gitlab.gnome.org/GNOME/gtk/-/tree/gtk-3-24/gtk/theme/Adwaita , although it doesn't seem to completely correlate with the default "Adwaita" theme that's also available.

Where would I find documentation on the available CSS tags, classes, IDs, etc? Unfortunately there's a lot of outdated information around, advising things that presumably don't work any more as of GNOME 3.

1 Answer 1


The solution is in multiple parts.

  1. To figure out what an app uses, activate the GTK inspector with environment variable GTK_DEBUG=interactive. This works well for stand-alone apps, but unfortunately not for everything. So...

  2. To use the inspector on core windows like the panels, put export GTK_DEBUG=interactive into .xsessionrc in your home directory. (Recommendation: Use a VM for this. Your desktop will be painfully slow with the inspector active on every window.) This still doesn't work for Google Chrome, but it does get information about panels.

  3. There is no dedicated "Urgent" status. The panel uses checkbuttons for the window switcher, with the active window checked; urgent windows get flipped "checked, not-checked, checked, not-checked" for a while, then settled on checked. So far I have found no way to style urgent windows differently from the currently active window.

So the final directive is:

.xfce4-panel .tasklist button:checked {
    background: #c3d6ef;

And now active and urgent windows are more visible.

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