<div>
    <style>
        body @popupContainer {
            border: @popup_border;
            border-radius: 0.35ex;
            background: @popup_bg;
            padding: 1em;
            box-shadow: 0em 0.15ex 0.7em rgba(0, 0, 0, 0.3);
            transition: opacity 0.4s;
            box-sizing: border-box;
            visibility: hidden;
        }
    </style>
    <div anon-id="popupContainer"> </div>
</div>
