Site Loses Formatting when Refreshed (mobile)

The site works fine on PC, but on mobile devices can lose formatting when hitting the site title/home button or the home button from the toggle menu. The initial loading is generally ok (now), but when prompted to return to the Home page, it loads incorrectly. I seem to have fixed the issue (maybe?) using Safari but when trying to access via social media (i.e. Instagram), the problem is consistent. I’ve tried to clear the cache and disabling the plugins. I found that the formatting on the site will crash when the Spectra plugin is disabled altogether, but when active – the other pages do not have the same issue, only the home page. I’m guessing there’s a setting or CSS issue but still new to building sites/stores.

Any help is greatly appreciated.

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