title: CSS triangle with border
body: <p>I've made a css triangle like so:</p>
  
  <pre><code>width: 0; 
  height: 0; 
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent; 
  border-right:10px solid blue;
  </code></pre>
  
  <p>How can I add a border to the triangle?</p>