adding a close button?

[ibnYusrat]

What would be the easiest way to add a transparent png close button to the top-right corner?

[ibnYusrat]

I added a close button by making the following modifications in uglypop.js:

Right below line # 12: that says var overlay_wrapper = document.createElement('div');
I added:

    close_button.id = 'uglipop_close_button';
    close_button.setAttribute('style', 'z-index:999999;position:fixed;right: -7px;top:-7px; cursor:pointer; filter: drop-shadow(5px 5px 5px #222);');
    close_button.innerHTML = "<img src='path/to/close-button.png' />";

And then below line # 25 that says: overlay_wrapper.appendChild(overlay); I added:
content_fixed.appendChild(close_button);

And that was it. I hope someone else finds it useful someday. Don't forget to update path to your close-button PNG.