bs_columns.html

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Voronoi Editor</title>
    <link rel='shortcut icon' href='favicon.ico' type='image/x-icon' />

    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
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    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>

    <link href="https://cdn.jsdelivr.net/gh/gitbrent/bootstrap4-toggle@3.6.1/css/bootstrap4-toggle.min.css" rel="stylesheet">
    <script src="https://cdn.jsdelivr.net/gh/gitbrent/bootstrap4-toggle@3.6.1/js/bootstrap4-toggle.min.js"></script>
    <script src="./libs/FileSaver.js"></script>
</head>
<body>
    <script src="src/main_bs.js" type="module"></script>
</body>
</html>