- To be able to use the latest/adequate version of sass, install sassc
- meson will regenerate the CSS every time you modify the SCSS files.
- Note that meson always builds out-of-tree, so the modified css files will appear in your builddir.
The Adwaita theme comes in 4 variants: light, dark, hc (highcontrast) and
hc-dark (highcontrast inverse). The generated CSS files for the variants
are called Adwaita-$variant.css. For technical reasons, GTK adds one level
of include wrappers around these, which are called gtk-$variant.css.
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.
It is very likely your change will happen in the _common.scss file. That's where all the widget selectors are defined. Here's a rundown of the "supporting" stylesheets, that are unlikely to be the right place for a drive by stylesheet fix:
_colors.scss - global color definitions. We keep the number of defined colors to a necessary minimum, most colors are derived from 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.
You can read about SASS at http://sass-lang.com/documentation/. Once you make your changes to the _common.scss file, libadwaita will rebuild the CSS files.