Strange underlines in font-awesome CSS

Question

When I hover on font-awesome\'s icons (when they\'re stacked together) like below (see picture). I get these strange underlines. Any idea where they could come from?

Answer 1

Fontawesome great and fun. But if you are using it as font, this is expected behaviour.

Add text-decoration to every state. If you don't add :link it will show purple underline, very hard to see but it is there.
If you don't add :active it will show red underline when clicking, very visible.

a:hover, a:focus, a:active, a:visited, a:link{
    text-decoration: none;
}