There should be a continual 1px-wide solid black border around the inline box when it is hovered over or activated.
It appears that an invisible
outline is always drawn around the border-box of an A element, even in it's normal state. On :hover or :active, it seems as though the bottom border is incorrectly drawn outside the perimeter of the elements border-box, and this cancels out the
outline value (whether initially invisible, or declared).