:empty and the empty space between tags

Useful to know

:empty selects an item without children. In usual browser implementations, text nodes, including empty spaces and new lines, affect the match. Comments do not. [1]

<div></div> matches, while <div> </div> may not match because of the interval. This is important in a template that leaves indentations in an empty container. MDN also describes the difference between the newer definition in specification and implementations. For a critical condition such as "no results" it is more reliable for the application to note it explicitly, rather than relying only on a visual void.