The :link selector is a pseudo-class that targets all unvisited anchor (a) elements on a page.
When used in combination with the :hover, :link must be used first, or else not be defined at all, in order for the :hover styles to work. This is because they are equally specific, so if :link came after, those styles would override the hover styles.
The :link pseudo-class will target all anchor elements that have an href attribute, even if the href has an empty value.