[gnome-shell] theme: provide some info on the SASS theming

[Jakub Steiner <jimmac src gnome org>]

commit db2b83edf324d50338f432c7d910023c2fbcc9b3
Author: Jakub Steiner <jimmac gmail com>
Date:   Tue Feb 24 17:41:56 2015 +0100

    theme: provide some info on the SASS theming
    
    - use bundles for using SASS v 3.4+
    - README
    - shell script

 data/theme/Gemfile       |    1 +
 data/theme/README        |   35 +++++++++++++++++++++++++++++++++++
 data/theme/parse-sass.sh |    3 +++
 3 files changed, 39 insertions(+), 0 deletions(-)
---
diff --git a/data/theme/Gemfile b/data/theme/Gemfile
new file mode 100644
index 0000000..99f8e2a
--- /dev/null
+++ b/data/theme/Gemfile
@@ -0,0 +1 @@
+gem "sass", "~> 3.4.0"
diff --git a/data/theme/README b/data/theme/README
new file mode 100644
index 0000000..c24ec99
--- /dev/null
+++ b/data/theme/README
@@ -0,0 +1,35 @@
+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 sofwtare installed, as described below)
+* To be able to use the lates/adequate version of sass, install ruby, gem, sass & bundle. 
+  On Fedora F20, this is done with `sudo dnf install rubygems && gem install bundle && bundle install`
+  from the same directory this README resides in.
+
+How to tweak the theme
+----------------------
+
+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 form a handful of basics. It is an exact copy of the gtk+ 
+                      counterpart. Light theme is used for the classic theme and dark is for GNOME3 shell 
+                      default.
+
+_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, 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`.
diff --git a/data/theme/parse-sass.sh b/data/theme/parse-sass.sh
new file mode 100755
index 0000000..e9cda25
--- /dev/null
+++ b/data/theme/parse-sass.sh
@@ -0,0 +1,3 @@
+#!/usr/bin/bash
+
+bundle exec sass --update --sourcemap=none .