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<!DOCTYPE html>
<html>
<head>
<title>Bootstrap 101 Template</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- Bootstrap -->
<link href="css/bootstrap.min.css" rel="stylesheet" media="screen">
</head>

<body>
<h1>Hello, world!</h1>

<script src="//code.jquery.com/jquery.js"></script>
<script src="js/bootstrap.min.js"></script>
</body>
</html>

<link href="css/bootstrap.min.css" rel="stylesheet" media="screen">

<link href="bootstrap.min.css" rel="stylesheet" media="all">

<link href="css/bootstrap.min.css" rel="stylesheet" media="all">

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css">