<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <style>
      div{
        border:10px solid green;
        font-size:60px;
      }
      @media(max-width:800px) {
        div{
          display:none;
        }
      }
    </style>
  </head>
  <body>
    <div>
      Responsive
    </div>
  </body>
</html>

External CSS

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External JavaScript

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