[Samples]: Link to theming recipe from the samples page.

Author: dglazkov

samples/index.html

@@ -37,6 +37,8 @@ <h2>Shadow DOM Code Samples</h2>
 
 <p>It all begins with a basic recipe for making a well-encapsulated <a href="contacts-widget.html">Contacts Widget</a>.</p>
 
+<p>A more advanced recipe shows how <a href="http://dev.w3.org/csswg/css-variables/">CSS Variables</a> could be used to attenuate styling of shadow DOM for things like <a href="widget-theming.html">theming</a>.</p>
+
 <p>The <a href="replay-extension.html">DOM replay extension</a> example/recipe illustrates a technique that can be used to inject new user interface into an existing document without disturbing document's structure.</p>
 
 <p>There's a fairly involved <a href="../spec/shadow/index.html#shadow-dom-example">example</a> in the <a href="../spec/shadow/index.html">Shadow DOM</a> specification.</p>