index.html

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Progress Steps</title>
    <meta name="description" content="">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="index.css">
</head>

<body>
    <div class="container">
        <div class="progress-container">
            <div class="progress" id="progress"></div>
            <div class="circle active">1</div>
            <div class="circle">2</div>
            <div class="circle">3</div>
            <div class="circle">4</div>
        </div>
        <button class="btn" id="prev" disabled>Prev</button>
        <button class="btn" id="next">Next</button>
    </div>


    <script src="index.js" async defer></script>
</body>

</html>