title: Add custom css rule with angular
body: <p>I want to make an application with dynamic theming. For example, there is a button, you click it and color of some elements changes by some rule. First idea - do it with </p>
  
  <pre><code>&lt;style type="text/css" ng-bind="ownStyle"&gt;&lt;/style&gt;
  </code></pre>
  
  <p>and init ownStyle in $rootScope:</p>
  
  <pre><code>$rootScope.ownStyle = "* {color: green }";
  </code></pre>
  
  <p>But it seems awful + it's too hard to write css rules as string. Is there a more elegancy way to do it?</p>