Header misbehaving and blocking Page Title Bar text

Two problems (on desktop, not mobile):

1) The header overlaps with the Page Title Bar on every page other than Main (see https://faunafables.com/shop/)

2) In this Airi demo (https://airi.la-studioweb.com/), you can see that the header changes color on the main page when you start to scroll (text and logo go from white to black). But if you go to any other page (like https://airi.la-studioweb.com/pages/about-us/), the header is static and always black, even when you scroll. This doesn’t happen for me — the functionality on the main page is the same as for all other pages: the header starts off as white text and changes color to black when you scroll. This is problematic because the background is white on those pages (so you can’t see the header text by default). I’d like the functionality to match the Airi demo — on all non-main pages, black header that doesn’t change color on scroll.

The page I need help with: [log in to see the link]