Custom Alert

Bootstrap 4 Alert

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.6/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js"></script>
<div class="alert alert-custom  fade in alert-dismissable show" style="margin-top:18px;">
 <button type="button" class="close" data-dismiss="alert" aria-label="Close">
    <span aria-hidden="true" style="font-size:20px">×</span>
  </button>    <strong>Success!</strong> This alert box indicates a successful or positive action.
</div>

CSS

.alert-custom{
  background-color:#6089D5;
  color:#fff;
}