Re-configured samples page.

src/site/samples/countdown/index.markdown

+---
+layout: default
+title: Countdown
+group_id:  "working_with_the_dom"
+live_example_url: /docs/tutorials/indexeddb/examples/count_down/out/web/count_down.html
+header:
+  css: ["/samples/samples.css"]
+---
+
+<h1>{{ page.title }}</h1>
+
+Enter a name date and time and click the plus (+) button.
+
+This program shows you how to store and retrieve data on the client-side using
+IndexedDB.
+
+IndexedDB is one kind of local storage supported by many browsers that any web
+app can use to store and retrieve data on the client. IndexedDB is an indexed
+database in which each record is identified by unique ID.
+
+In brief, to save a record in an IndexedDB:
+
+- check for browser support
+- create or open a database
+- create or open an object store on the database
+- create a transaction on the object store
+- add the record to the database
+- handle transaction completed or error
+
+
+Read this [tutorial](/docs/tutorials/indexeddb) for
+more detail, or read the
+[source](https://github.com/dart-lang/dart-tutorials-samples/tree/master/web/stopwatch).
+
+<iframe class="running-app-frame"
+        style="height:400px;width:50%;"
+        src="{{page.live_example_url}}">
+</iframe>
+
+<p>See all <a href="/samples/">samples</a></p>