My test

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<!DOCTYPE HTML>  

<title>Print Order Form</title>

  
<body onload="window.print();">

<div>
  <h2 class="text-center"><span class="label label-default">Order Form Details</span></h2><br>
  <table class="tablesorter table table-hover table-responsive">
    <thead>
      <tr>
        <th>Name</th>
        <th>Surname</th>
        <th>Telephone</th>
        <th>Postal Code</th>
        <th>Priority</th>
      </tr>
    </thead>
    <tbody>
    <tr>
        <td>1</td>
        <td>1</td>
        <td>1</td>
        <td>1</td>
        <td>1</td>
      </tr>
    </tbody>
  </table>
</div>

</body>

CSS

th {
       background-color: #C8C8C8;
}