title: Height percentage not working in CSS
body: <p>I am trying to use height property using percentages, but it doesn't work. I want to use percentage so it looks fine in any resolution.  </p>
  
  <pre><code>&lt;div id="bloque_1" style="height: 80%;background: red"&gt;   
  &lt;/div&gt;
  </code></pre>
  
  <p>How can I make it work?</p>