CSS A:visited....why wont this work?

a.blackunderline:link,a.blackunderline:Visited,a.blackunderline:hover,a.blackunderline:active {
color: #000000;
text-decoration: underline;
font-size: 10px;
<a href="/" class="blackunderline">bibble</a>

I know that there a re posts all over the forum about this but I couldnt find one that actually answered my question…ive adjusted the CSS for everyh quirk ive found, but the visited state changes to white regardless of what I try, when it should stay black?!

If ANYONE could help id be most gratefull!