Massive cleanup

- Simpler main nav on all pages
- Back to purple masthead on homepage instead of dark graphite
- Active link styles on the main nav
- Cleaned up sidebar nav
- New docs layout name
- Homepage copy edits
- Updated bright purple docs color

docs/getting-started/javascript.md

@@ -1,5 +1,5 @@
 ---
-layout: page
+layout: docs
 title: JavaScript
 group: getting-started
 ---