Bug report on the site itself: with the way you’ve styled <i>both</i> body and html, body is a separate scrolling pane from the document scroll area, which causes the header and the “give feedback” buttons to sit on top of the scroll bar, and breaks keyboard navigation (arrow keys, Space, Page Down, <i>&c.</i>) until you focus the body (by clicking on the page or with Tab). A simple additive way of fixing this is to set `overflow-x: unset` on at least one of html and body (if you just do one, it actually doesn’t matter which, because html and body are a bit special), but removing the offending overflow declarations altogether would be better. A top-level `overflow-x: hidden` is generally a bad idea anyway—if it changes anything, it suggests that you’ve got some other styles somewhere wrong (though there <i>are</i> one or two genuine cases where there’s no good alternative), and doing things that way invariably ends up going wrong and truncating important content sooner or later.