JSFiddle - React, Tailwind, and code Playground

HTML

<html>

  <head>
    <title>Design</title>
    <link rel="stylesheet" type="text/css" href="css/store.css">
    <script type="text/javascript" src="javascript/js.js"></script>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
  </head>

  <body>
    <ul>
      <li id="left"><a href="#home">Company</a></li>
      <li id="left"><a href="#home">Sales</a></li>
      <li id="left"><a href="#home">About</a></li>
      <li id="left"><a href="#home">Contact</a></li>
      <li id="right1"><a href="">Cart</a></li>
      <li id="right2" onclick="myFunction()"><a href="">Geolocate</a></li>
    </ul>

    <dialog id="myDialog">Your IP address:
      <?php echo $_SERVER['REMOTE_ADDR']; ?>
    </dialog>

    <div id="items">
      <ul>
        <li id="left"><a href="">Home</a></li>
        <li id="Cars"><a href="">Super Cars</a></li>
        <li id="Cars"><a href="">Topic 2</a></li>
      </ul>

      <div id="homepage">
        <span><p> Welcome to the store</p></span>
      </div>

      <div id="showCars">
        <div class="productBox">
          <div class="productPicture">
          </div>
        </div>
      </div>
    </div>

  </body>

</html>

CSS

ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #363377;
  border-bottom: 1px solid white;
}

li a {
  display: inline-block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

#left,
#Cars {
  float: left;
  border-right: solid 1px #fff;
}

#right1,
#right2 {
  float: right;
}

#left:hover,
#right:hover,
#Cars:hover {
  background-color: #555;
}

body {
  margin: 0px;
  padding: 0px;
  font-family: tahoma;
  background-image: "/img/bg.jpg";
}

p {
  text-align: center;
}

#items {
  display: inline-block;
  border: 1px solid black;
  padding: 10px;
  margin-top: 25px;
  margin-left: 225px;
  margin-right: 225px;
  position: absolute;
  width: 80%;
  height: 80%;
  -moz-box-shadow: 1px 2px 4px rgba(0, 0, 0, 0.5);
  -webkit-box-shadow: 1px 2px 4px rgba(0, 0, 0, .5);
  box-shadow: 1px 2px 4px rgba(0, 0, 0, .5);
  background: white;
  overflow: hidden;
}

.productBox {
  border: 2px solid black;
  width: 200px;
  height: 300px;
  margin-top: 5px;
  text-align: center;
}

.productPicture {
  border: 1px solid black;
  width: 90%;
  height: 150px;
  margin: 0 auto;
  margin-top: 5px;
  padding: 5px;
  display: inline-block;
}

#showCars {
  display: none;
}