theming docs

css/theme/README.md

+## Dependencies
+
 Themes are written using Sass to keep things modular and reduce the need for repeated selectors across files. Find out how to install Sass here http://sass-lang.com/, once Sass is installed run the follwing command to start monitoring the source files for changes.
 
 ```
 sass --watch css/theme/source/:css/theme --style expanded
-```
+```
\ No newline at end of file
+
+
+
+## Creating a Theme
+
+To create your own theme, start by duplicating any ```.scss``` file in [/css/theme/source](https://github.com/hakimel/reveal.js/blob/master/css/theme/source). Each theme does four things in the following order:
+
+1. **Include [/css/theme/template/mixins.scss](https://github.com/hakimel/reveal.js/blob/master/css/theme/template/mixins.scss)**  
+Shared utility functions.
+
+2. **Include [/css/theme/template/settings.scss](https://github.com/hakimel/reveal.js/blob/master/css/theme/template/settings.scss)**  
+Declares a set of custom variables that the template file (step 4) expects. Can be overridden in step 3.
+
+3. **Override**  
+This is where you override the default theme. Either by specifying variables (see [settings.scss](https://github.com/hakimel/reveal.js/blob/master/css/theme/template/settings.scss) for reference) or by adding full selectors with hardcoded styles.
+
+4. **Include [/css/theme/template/theme.scss](https://github.com/hakimel/reveal.js/blob/master/css/theme/template/theme.scss)**  
+The template theme file which will generate final CSS output based on the currently defined variables.