title: How to animate a background size using jquery
body: <p>I want to animate the background of my website so that when the user enters it, the background starts at a size of 60% and goes up until 100% over the course of several seconds. </p>
  
  <p>I tried using animate in jQuery like below, but the console says 'Unexpected token -'. This worked for opacity in another piece of code. </p>
  
  <p>What am I doing wrong?</p>
  
  <pre><code>$(document).ready(function() {
      $('.left-content').animate(
      {
          background-size: 100%
      },
      3000);
  })
  </code></pre>