css stying a visited link

I have below css style for several links:

.to开发者_运维百科p_header {
   background-color:#3B5998; 
   height:35px; 
   margin-left:0px; 
   margin-right:0px; 
   top:30px; 
   position:relative;
   left: 1px;
}

.top_header a, .top_header a:active, .top_header a:hover, .top_header a:focus {
  color:white; 
  font-size:x-large; 
  font-family:Arial; 
  line-height:35px; 
  text-decoration:none
}

.top_header a:visited {
  color:yellow; 
  font-size:x-large; 
  font-family:Arial; 
  line-height:35px; 
  text-decoration:none
}

a:visited colour is set to yellow. However the links remain yellow at all times regardless of whether they have been visisted.

I basically want to change the colour after the user has clicked on a link.

Thanks Bruce

They show yellow because you have already visited them. try private/incognito/whatever-your-browser-has-on-the-name-of-private-browsing window. or clean your browsing history as @kleinohad suggests :)

Works fine for me (http://jsfiddle.net/uCG44/) try to clean your cache and history and test it again