Node visited

I need to show the nodes already visited in another color.
I've changed the color of ".ui-btn:visited,html .ui-bar-a .ui-btn:visited,html .ui-body-a .ui-btn:visited,html body .ui-group-theme-a .ui-btn:visited,html head+body .ui-btn.ui-btn-a:visited" class in jquery.mobile-1.4.5.min.css, but not reflected in the app.
What can be happening?