title: Polymer share styles across elements
body: <p>I need to share styles across multiple Polymer elements. Is it acceptable to create a "styles.html" file and then import that into my different elements or would this start to have performance implications as the app grows? I know for 0.5 there was a core-styles but it kind of seems unnecessary if imports will work just as well.</p>
  
  <p>styles.html</p>
  
  <pre><code>&lt;style&gt;
    button {
      background: red;
    }
  &lt;/style&gt;
  </code></pre>
  
  <p>my-button.html</p>
  
  <pre><code>&lt;link rel="import" href="../bower_components/polymer/polymer.html"&gt;
  &lt;link rel="import" href="../styles/main-styles.html"&gt;
  &lt;link rel="import" href="../behaviors/mixins.html"&gt;
  
  &lt;dom-module id="my-button"&gt;
    &lt;template&gt;
      &lt;button&gt;{{text}}&lt;/button&gt;
    &lt;/template&gt;
  &lt;/dom-module&gt;
  
  &lt;script&gt;
    Polymer({
      is: 'my-button',
      behaviors: [ButtonBehavior]
    })
  &lt;/script&gt;
  </code></pre>