Make sure that a visitor using only the keyboard does not get stuck on the page

If visitors can navigate to an item on the page with their keyboard, but cannot navigate away from it, it is called a keyboard trap. To get out of a keyboard trap, it is often needed to use the mouse (or other pointing device) or to completely reload the page. This is not an option for visitors who cannot use the mouse. A keyboard trap can be caused by plugins.

Make sure it is possible to use the keyboard to navigate all around the page.