Update part12

part12/README.md

@@ -1,9 +1,6 @@
-Part 11
+Part 12
 =======
 
-The instructor will paste notes from the lesson, including code examples from
-Q&A, in [this document](https://docs.google.com/document/d/1ApuSOk9DP0YsQrxhW7-WE8UOEAV4PPnLDDeqUOL2o5k/edit?usp=sharing).
-
 ## Installation
 
 ```bash
@@ -18,3 +15,13 @@ elm-package install
 ```bash
 elm-live Main.elm --open --pushstate --output=elm.js
 ```
+
+## Compiling CSS
+
+```bash
+elm-css Stylesheets.elm
+```
+
+## References
+
+* [Elm CSS documentation](http://package.elm-lang.org/packages/rtfeldman/elm-css/latest)