configure.html

<!DOCTYPE html>
<html>

<head>
    <link rel="stylesheet" href="styles/main.css" type="text/css" />
    <script src="libs/jscolor.js" type="text/javascript"></script>
</head>

<body>

    <div id="topbar">
        Theme Color Changer
    </div>
    <div style="text-align:center">

        <input class="jscolor" id="color" value="002157">
        <div style="margin-top:10px;">
            <button id="changeColor">Change Theme Color</button>
            <p style="padding:10px">
                Changing the theme color will change the color of the title bar on installed PWAs.
            </p>
        </div>

    </div>

    <script src="configure.js"></script>

</body>

</html>