Navbar hides header on Firefox
When loading a documentation page on a specific header in Firefox, e.g. usage#basic-usage, when coming from a different page, the navbar hides the section header.
usage#basic-usage shows as:

I expect usage#basic-usage shows as:

The behavior seems to work correctly on Chrome. When moving between section headers on the same page, it also seems to work fine on Firefox.
I tried to apply this fix, but it did not seem to help (though I can't guarantee I did that right).
Using Firefox 66.0.3 (64-bit).
For me it works like expected in Chrome and FF.

I just tried again and it works in Chromium, but not in FF. FF only works if I narrow the window a bit. @nok shouldn't the heading at the top be 'basic usage'?
It depends how it's implemented. Either you use the basic anchor tag #id or scrollTo() in JavaScript. In general you use the static variant as fallback. However it's not a critical behaviour.
From your screenshot it seems to have skipped even more of the page? Following the link in the original post should leave you at the top of the page exactly, having the 'Basic Usage' title fully visible (note that after opening the site, if I switch between headers in the sidebar, 'Basic Usage' will be displayed correctly, it is only on following the link the first time).