Testing stye in extended polymer elements

How can I get styling to override the parent element?

by gianlucaguarini

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/polymer/0.3.4/platform.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/polymer/0.3.4/polymer.js"></script>

<polymer-element name="polymer-el">
  <template>
      Hi!
  </template>
  <script>
    Polymer('polymer-el')
  </script>
</polymer-element>

<polymer-el>Matt</polymer-el>