W3Schools CSS CDN
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
Yasin
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<link rel="stylesheet" type="text/css" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">