Collapsible div

<!DOCTYPE html>
<html>

  <head>
    <meta charset="utf-8" />
    <title></title>
    <link rel="stylesheet" href="style.css" />
    <script data-require="jquery" data-semver="3.1.1" src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
    <script src="script.js"></script>
  </head>

  <body>
    <div>
      <div class="menu" style="display:none;"></div>
    <h1 style="position:relative; top: 0;">Basic Collapsible div plunk!</h1>
    <!-- Put your html here! -->
    <button class="clickMe">click</button>
    </div>
  </body>

</html>

// Add your javascript here
$(function(){
  $('.clickMe').click(function(){
     $('.menu').slideToggle( "slow", function() {
        // Animation complete.
    });
  });
});

/* Put your css in here */

h1 {
  color: red;
}

body {
  padding: 0;
}

.menu {
  width: 100%;
  height: 800px;
  background: black;
}