I upgraded to Fedora 21, which spotlights GNOME 3.14 (plus the relevant GTK+ material). Unfortunately it seems that this particular update mangles a lot of my older themes, written for now-aging versions of GNOME 3. Where previously they may have squeaked by, they now look a little out-of-place.

I don't presume to re-invent the wheel: I would be very happy to take a pre-existing CSS template (e.g. the default Adwaita 3.14 spec) and tweak it here and there to my liking; there will be no fancy flying. Imagine the hair I tore out when I peeked at /usr/share/themes/Adwaita/gtk-3.0/gtk.css:

/* Adwaita is the default theme of GTK+ 3, this file is not used */

That puts me in a pickle. I lack the Google-fu to dig the documentation up about where this might be (worse, I have a gut feeling this is something implicitly obvious to GNOME people that I have been missing out on), and for some reason the GNOME developer website resists my attempts at researching their theming specification.

In short, I'd like to find a virgin theme specification for GNOME 3.14, assuming one is extant. How may I do this, or how may I modify my approach?


There's only a single line in that particular .css file because the default theme (Adwaita) comes as a binary:

Adwaita is a complex theme, so to keep it maintainable it's written and processed in SASS, the generated CSS is
then transformed into a gresource file during gtk build and used at runtime in a non-legible or editable form.

Since the code has been included in gtk+, you can view the source files HERE. As per their readme:

_colors.scss        - global color definitions. We keep the number of defined colors to a necessary minimum, most colors 
                      are derived form a handful of basics. It covers both the light variant and the dark variant.
_colors-public.scss - SCSS colors exported through gtk to allow for 3rd party apps color mixing.
_drawing.scss       - drawing helper mixings/functions to allow easier definition of widget drawing under specific context.
                      This is why Adwaita isn't 15000 LOC.
_common.scss        - actual definitions of style for each widget. This is where you are likely to add/remove your changes.

The reference .css files are:


Here is an older how-to, some stuff no longer applies (as I said, the source code is in gtk+ now, as gnome-themes-standard was deprecated) but it should get you on the right path:

How to hack GNOME Adwaita GTK theme


I'm copying my own TLDR here from a similar question about window topbar colors


@import url("resource:///org/gtk/libgtk/theme/Adwaita/gtk-contained-dark.css");

headerbar.titlebar:active {

row:selected:backdrop {

To debug and find fitting CSS Selectors, open a GTK3 app with environment variable GTK_DEBUG=interactive. For example,

GTK_DEBUG=interactive nautilus

This should open a inspector for the GTK window. If it's not there, press Ctrl+Shift+I.

screenshot of inspector

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