Incorrect display of an included page

[iron-mesh]

I've noticed that the page display is not the same as the original page. As you can see, the space on the right side is not being used.

Original page

Included page

I have tried to fix this issue and checked the CSS properties. I made a minor change to style.css and the page now displays correctly.

I commented 1 line in style.css

div.plugin_include_content {
  /*display: flow-root;*/
  margin-bottom: 1.4em;
}