index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>QuickStart</title>

    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css">
    <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css">
    <link rel="stylesheet" href="style.css">
    <link rel="stylesheet" href="assets/css/responsive.css">

    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"></script>
</head>
<body>
    
    
    
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"></script>
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</body>
</html>