<style type="text/css">
.error404{

}
.error404 h1{

}
</style>
<div class="row">
  <div class="col-md-9"  style="min-height:400px">
    <div class="error404">
      <h1>Opps, page not found[404]</h1>
      <a class="btn btn-warning" href="<?php echo site_url();?>">&lt; Home</a>
    </div>
  </div>
</div>  