update nav

docs/_data/nav.yml

 - title: Getting started
   pages:
-    # - title: Overview
-    # - title: Download
-    # - title: Contents
     # - title: JavaScript
-    # - title: Compiling
-    # - title: Customize
-    # - title: Flexbox
-    # - title: Support
     # - title: Accessibility
     - title: Introduction
     - title: Download
     - title: Browsers & devices
     - title: Options
+    - title: Flexbox
     - title: Build tools
     - title: Best practices
 
@@ -34,11 +28,6 @@
 
 - title: Components
   pages:
-    # - title: Reboot
-    # - title: Typography
-    # - title: Images
-    # - title: Code
-    # - title: Tables
     - title: Buttons
     - title: Button group
     - title: Button dropdown

docs/layout/media-object.md

 ---
 layout: page
-title: Media
+title: Media object
 group: layout
 ---
 
-Abstract object styles for building custom components (like blog comments, Tweets, etc) that feature a left- or right-aligned piece of content alongside textual content.
+The [media object](http://www.stubbornella.org/content/2010/06/25/the-media-object-saves-hundreds-of-lines-of-code/) is an abstract element used as the basis for building more complex and repetitive components (like blog comments, Tweets, etc). Included is support for left and right aligned content, content alignment options, nesting, and more.
+
+{% callout info %}
+**Heads up!** When [flexbox mode]({{ site.baseurl }}/getting-started/flexbox/) is enabled, the media object will use `flex` styles wherever possible.
+{% endcallout %}
 
 ## Contents