preferences.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Preferences</title>
        <meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" type="text/css" href="preferences.css">
    </head>
    <body>
        <div class="options-pane">
            <div class="option">
                <label>
                    <input type="checkbox" name="ignore-spaces">
                    Ignore preceeding spaces
                </label>
            </div>
            <div class="option">
                <label>
                    <input type="checkbox" name="add-space-end">
                    Add space before newline
                </label>
            </div>
        </div>
        <script src="preferences.js"></script>
    </body>
</html>