[CSS Help requested] How to remove the white space between the header &content

Site information:
WP: 4.6.1
Theme: Child theme of Sauron
Site: getleastrength.com

Problem:
There is a title above any content on a page.
I want that entire area removed, so that I can place a feature optin box in that place.

I have identified the text for the title as
.page-header

And am able to remove it with:

.page-header {
 Display: none;
 visibility: hidden;
 }

What happens when I do that is that the text itself is gone,
However, the white space between the header and the actual content is still there.

Things that I tried:
– Margin: 0px !important; or padding-top: 0px !important; as suggested in several google searches, but that doesn’t seem to do anything.

– many of the fixes that are shown in any of the google searches when I search for “How to remove the white space between header and body” however it seems that this theme is using different CSS tags than any of the reported fixes for this issue.

What is interesting is that the preview site in my current theme does not have this issue.
You can find the theme demo here: themedemo.web-dorado.com/theme-sauron/

Could anyone help me to correct this issue?
Would be much appreciated!