be available only in mobile versions or on smaller devices. For example, as
we hide major pieces of content, we could replace them with navigation to
that content, or with a different navigation structure altogether.
Note that we haven’t used visibility: hidden here; this just hides the
content (although it is still there), whereas the display property gets rid
of it altogether. For smaller devices, there is no need to keep the mark-up
on the page — it just takes up resources and might even cause unnecessary
scrolling or break the layout.