Beacon code sample returns a `SyntaxError` and a 404 stylesheet

[cvan]

Chrome Version 38.0.2125.104
(with flag disabled)

Upon loading the Beacon code sample, I see two errors in my console:

GET http://updates.html5rocks.com/samples/styles/main.css                index.html:45
Uncaught SyntaxError: Unexpected token (                                               index.html:76