Side Nav Bar Question

I found this video on youtube about doing a side navbar, having issues getting it to close, what am I doing wrong?

<!DOCTYPE html>

<html>

<head>

  <title>Responsive Animated Sidebar Menu</title>

  <script defer src="https://use.fontawesome.com/releases/v5.0.7/js/all.js"></script>

  <link rel="stylesheet" href="style.css">

<script>

function openSlideMenu(){

document.getElementById('menu').style.width = '250px';

document.getElementById('content').style.marginLeft = '250px';

}

function closeSlideMenu(){

document.getElementById('menu').style.width = '0';

document.getElementById('content').style.marginLeft = '0';

}

</script>

</head>

<body>

  <div id="content">

  <span class="slide">

  <a href="#" onClick="openSlideMenu()">

  <i class="fas fa-bars"></i>

</a>

  </span>

  <div id="menu" clSS="nav">

  <a href="#" class="close" onclick="closeSideMenu()">

<i class="fas fa-times"></i>

</a>

<a href="#">Home</a>

<a href="#">About</a>

<a href="#">Services</a>

<a href="#">Contact</a>

  </div>

  <h1>S.T. Graffix Menu</h1>

</div>

</body>

</html>