title: Polymer and shadow DOM external styling
body: <p>Hi I'm experimenting with Polymer and trying to style some polymer paper modules... In Polymer 1.0 they added this new properties in the CSS internal to shadow DOM's module... I am trying to change a color that is dependent on one of this properties <code>--paper-input-container-focus-color</code> for the <a href="https://elements.polymer-project.org/elements/paper-input?active=paper-input-container" rel="nofollow" title="paper input container module"><code>paper-input-container</code></a> module but I could not find any clear documentation or guide on how to actually access that property from...</p>
  
  <p>I can style it overriding the CSS property via <code>/deep/</code> or <code>::shadow</code> but from my understanding this new method is supposed to avoid using those 2... </p>
  
  <p>Can anyone point me in the right direction???</p>
  
  <p><strong>CLARIFICATION:</strong></p>
  
  <p>I am interested in the <a href="https://elements.polymer-project.org/elements/paper-input?active=paper-input-container" rel="nofollow">mixins</a> Google introduced in polymer... that make use of <code>@apply(--foo-bar)</code></p>