Dotted border appearing after link click

A dotted border appears around the hyperlink when clicked. I want to remove the dotted border appearing around the link (happens only in firefox). I have the following styles applied to anchor tag:

a, a:hover, a:link, a:active {
    text-decoration: none;
    color: #777777;
}

Link appears fine > click on the link > this box appears > goes off when clicked somewhere outside

URL: http://www.boxleak.in/ritgan

P.S.: Bootstrap is also included.