Absolum header on all pages?

My website is https://www.todayiwatchedamovie.com

I’m using the Absolum theme. I know a little about CSS, and I’ve changed a few things on the back end…mostly font-related things.

I suddenly noticed today that on every page except for the Home page, the menus and logo disappear, and the background is blue rather than black. (Example: https://todayiwatchedamovie.com/about/)

Can anyone tell me which file(s) I need to edit to fix this, and what code needs to be added to make it work? Please let me know if any more information is needed.

Thanks!