When using custom CSS to hide the dashboard, a footer is added

I am trying to have a dashboard embedded as an iFrame in another project, so I wanted to remove the header. I added the following as custom CSS

.dashboard div .header{
  display: none;

It works, however by hiding the header, it has added a "footer" (not sure that it's a footer, just don't know what to call it).

Here is the same dashboard, except with the header showing and no "footer"

I have edited around with a number of different settings, but nothing seems to remove the "footer" other than adding the header back. Hoping someone more knowledgable can help point me in the right direction. My goal is as compact a dashboard as possible.