I have a hub site that has a custom header and footer configured via HTML/CSS. You can see the header in the screenshot below. It has a drop down as well.

My problem is that this header shows up on the landing page of the hubsite but it disappears from other hub pages. My understanding is that we only configure one header/footer for the hubsite and it applies to all the pages of that hubsite. The header and footer behave normally when I choose the standard header option instead of custom code.
I need help figuring out why my custom header does not show. I don't know if I need to do something special to my code or if I am missing some step.
Thank you!