<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div class="container">
<div class="row d-flex flex-row justify-content-center mt-5">
<div class="col-lg-5">
<div class="card">
<div class="card-body">
<form method="POST" action="">
<div class="form-group">
<input type="text" name="username" class="form-control" placeholder="username">
</div>
<div class="form-group">
<input type="password" name="password" class="form-control" placeholder="password">
</div>
<div class="form-group">
<button class="btn btn-primary btn-lg btn-block">
login
</button>
</div>
</form>
</div>
</div>
</div>
</div>
</div>
