title: Invalid background property
body: <p><a href="https://i.stack.imgur.com/wwcza.png" rel="nofollow noreferrer">enter image description here</a></p>
  
  <p>I am getting a background image from external CSS to display. When I check in the element inspector it shows me invalid property used.</p>
  
  <pre class="lang-css prettyprint-override"><code>body {
    font-family: 'Helvetica Neue', Arial, Helvetica, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background-image: url(../img/background.jpg);
    background-size: cover;
    overflow: hidden;
  }
  </code></pre>
  
  <p>What am I doing wrong here?</p>