This is because you have the "highlight current page" feature and all of your links are blank. So it thinks that all the links are the current page and highlights them all.
Browse to it with a page name like:
index.html
or set the links correctly so that it will display them properly.
Then you are left with just the text color issue on the main level.
To fix that, update:
#outerWrapper a:visited {index.html# (line 159)
color:#FFFFFF;
font-weight:bold;
text-decoration:none;
}
that seems to be overriding the color of the link when visited, and they are all marked as visited since they link to the page being viewed currently.