title: Assign a CSS Element a Class
body: <p>Is it possible to make all <code>h3</code> elements be of the class <code>responsive-heading</code> through CSS. For a better idea of what I am trying to achieve please see the CSS code below:</p>
  
  <pre><code>h3 { .responsive-heading }
  
  /* The class responsive-heading is implemented inside another CSS file and its contents are:
      .responsive-heading { font-size: 30px; .... etc. }
  */
  </code></pre>
  
  <p>I am aware I could use Javascript and/or JQuery for assigning each <code>h3</code> the class <code>.responsive-heading</code> but I before I start doing that I'd rather know if there is a css way?</p>
  
  <p>In short: I want to apply <code>.responsive-heading</code> style to all <code>h3</code>. We hav hundreds of pages to update the H3 elements.</p>