title: Bold only the top and bottom borders of a div
body: <p>I would like to bold the border of a div.
  My problem is that i need to bold only the top and bottom borders.</p>
  
  <p>For example: if i have a div as a shape of a square it should look:</p>
  
  <pre><code>_______________
  
  
  
  
  
  _______________
  </code></pre>
  
  <p>How can i do it in css?</p>