Summary
-------

- Do not edit the CSS directly, edit the source SCSS files and process them with SASS (run 
  `./parse-sass.sh` when you have the required software installed, as described below)

- To be able to use the latest/adequate version of sass, install ruby, gem, sass & bundle.
  On Fedora 25, this is done with `sudo dnf install rubygems && gem install bundle && bundle install`
  from the same directory this `HACKING.md` resides in.

How to tweak the theme
----------------------

Flat-Plat is a complex theme, so to keep it maintainable it's written and processed in SASS.

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 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 Flat-Plat 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, you can either run the `./parse-sass.sh` script or keep SASS watching for changes as you
edit. This is done by running `bundle exec sass --watch --sourcemap=none .` If sass is out of date, or is
missing, you can install it with `bundle install`.

Useful Links
------------

Upstream theme sources:
- [GTK+ 3 or 4](https://github.com/GNOME/gtk/tree/master/gtk/theme/Adwaita)
  - [3.22.x](https://github.com/GNOME/gtk/tree/gtk-3-22/gtk/theme/Adwaita)
  - [3.20.x](https://github.com/GNOME/gtk/tree/gtk-3-20/gtk/theme/Adwaita)
  - [3.18.x](https://github.com/GNOME/gtk/tree/gtk-3-18/gtk/theme/Adwaita)
- [GTK+ 2](https://github.com/GNOME/gnome-themes-standard/tree/master/themes/Adwaita/gtk-2.0)
- [GNOME Shell](https://github.com/GNOME/gnome-shell/tree/master/data/theme)
  - [Sass sources](https://github.com/GNOME/gnome-shell-sass)

Tips:
- [Unity/Theming](https://wiki.ubuntu.com/Unity/Theming)
- [Material Design Guidelines](https://www.material.io/guidelines/)
- [Personal CSS Guidelines](https://github.com/nana-4/Flat-Plat/wiki/CSS-Guidelines)