I modified the #comment-tabs div to reside within an .embed-container div with the following CSS…
.embed-container {
position: relative;
overflow: hidden;
}
.embed-container iframe,
.embed-container object,
.embed-container embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
There is a brief description about a quarter way down in this article describing
Embedding Third-Party Content: The Responsive Iframe Problem
https://mobile.smashingmagazine.com/2013/05/29/the-state-of-responsive-web-design/
It seemed to work for my needs.