Fancybox 3: position the iFrame in the top of the viewport?

Question

How to position the iFrame in the top of the viewport? 20 pixels down?

Here is my Fancybox code:

$("[data-fancybox]").fancybox({
  iframe : {
    preload: false
  },
  .....
});

Answer 1

The content (except images) is centered using CSS only, therefore it would be something like this:

.fancybox-slide--iframe .fancybox-content {
    vertical-align: top;
    margin: 20px;
}