Styling accordion visited

Styling accordion visited

I'm trying to make the  ui accordion headers change when visited, something like the css a:visited {text-decoration: underline;} 

I have tried changing the ui css properties  but the visited properties seem impossible to change, any changes I do like changing 

.ui-state-default a:visited { color: #1c94c4; text-decoration: none; outline: none; }

to:

.ui-state-default a:visited { color: #1c94c4; text-decoration: underline; outline: none; }

have no effect.

Anybody have the solution??