Page-specific embedded html / css being implemented sitewide on mobile (works on desktop)

I’ve put a small html embed on some of the pages on my website to change the colour of the navbar. It works perfectly on desktop, but when I look at the site on mobile, it is implementing the css styling sitewide, rather than just on pages that added the html embed to.

I’ve tried moving the code to the page before body code section, and have also tried placing the html embed inside & outside the page wrapper, but it still has the same issue.

My site is Webflow - DiveUK

Some pages with the html embed code are location, blog & blog template. The embed code is not on the homepage, but when the homepage is viewed on mobile, while the logo, bottom border & dropdown font colour are correct, the burger menu lines and the dropdown menu background colour is incorrect

Any help appreciated