Unfortunately, there's no such thing in CSS! What we can do is to play with a little trick. The key is to identitfy this: Left 50% and Right 50%!
Consider a menu link as follows:
<ｕｌ>
<ｌｉ>Main Page < / ｌｉ>
< / u l>
First, we make ul {position: relative; right:50%}
What you'll see is the whole menu link shifts to the right!
Final stpe is to shift this whole thing 50% to the left. So, make things like:
li {position: relative; left:50%}
It's done. Check again your work and you'll see the whole menu now is placed at the center.
PS. Check another reference here: http://www.wowbox.com.tw/blog/article.asp?id=3008
