I know this is marked resolved, but I’ve been searching for a solution to this problem for days and I’d like to thank OP for the post. I think the Hatch theme has an issue with the header not being completely disabled when no image is uploaded, which causes it to pull information into the header container when attempting to build a static page.
I’d like to note, however, that for me, the above css had to be pasted into the editor (Appearance>Edit CSS) and not the custom css box under the Theme Settings, as instructed above. I’m very new to this and just installed and activated a child theme via a plugin, so I dunno if this is the cause of the discrepancy, but thought I’d mention it just in case anyone else stumbles across this issue…