datatable with fixedcolumn

HTML

<link rel="stylesheet" href="https://bootswatch.com/4/superhero/bootstrap.min.css">
<script src="https://bootswatch.com/_vendor/jquery/dist/jquery.min.js"></script>
<script src="https://bootswatch.com/_vendor/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
<link rel="stylesheet" href="https://cdn.datatables.net/1.11.3/css/dataTables.bootstrap4.min.css">
<script src="https://cdn.datatables.net/1.11.3/js/jquery.dataTables.min.js"></script>
<script src="https://cdn.datatables.net/1.11.3/js/dataTables.bootstrap4.min.js"></script>
<script src="https://cdn.datatables.net/fixedcolumns/4.0.1/js/dataTables.fixedColumns.min.js"></script>
<link rel="stylesheet" href="https://cdn.datatables.net/fixedcolumns/4.0.1/css/fixedColumns.bootstrap4.css">
<div class="container">
  <table id="example" class="table table-striped table-bordered nowrap" style="width:100%">
    <thead>
      <tr>
        <th>First name</th>
        <th>Last name</th>
        <th>Position</th>
        <th>Office</th>
        <th>Age</th>
        <th>Start date</th>
        <th>Salary</th>
        <th>Extn.</th>
        <th>E-mail</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>Tiger</td>
        <td>Nixon</td>
        <td>System Architect</td>
        <td>Edinburgh</td>
        <td>61</td>
        <td>2011/04/25</td>
        <td>$320,800</td>
        <td>5421</td>
        <td>[email protected]</td>
      </tr>
      <tr>
        <td>Garrett</td>
        <td>Winters</td>
        <td>Accountant</td>
        <td>Tokyo</td>
        <td>63</td>
        <td>2011/07/25</td>
        <td>$170,750</td>
        <td>8422</td>
        <td>[email protected]</td>
      </tr>
      <tr>
        <td>Ashton</td>
        <td>Cox</td>
        <td>Junior Technical Author</td>
        <td>San Francisco</td>
        <td>66</td>
        <td>2009/01/12</td>
        <td>$86,000</td>
        <td>1562</td>
        <td>[email protected]</td>
      </tr>
      <tr>
        <td>Cedric</td>
       ...

CSS

thead th,
tr.odd td {
  background-color: #2b3e50 !important;
}

tr.even td {
  background-color: #384f66 !important;
}

JavaScript

$(document).ready(function() {
    var table = $('#example').DataTable( {
        scrollY:        "300px",
        scrollX:        true,
        scrollCollapse: true,
        paging:         false,
        fixedColumns:   true
    } );
} );