If you want to override ancher tag style of corev4.css
A:visited
{
color:#0072bc;
text-decoration:none;
font-size:12px;
font-weight:bold;
text-decoration:underline;
}
A:visited
{
color:#0072bc;
text-decoration:none;
font-size:12px;
font-weight:bold;
text-decoration:underline;
}