The difficulty of implementation lies in: the two selectors first-child and last-child, and later the application of margin-left:-1px; and the technical processing of 33% and 34% width.
Another difficulty is: the implementation of box-shadow:1px 0 0 #F1F1F1 inset;.
Finally:
background:- webkit-gradient(linear, left top, left bottom, from(#f9f9f9), to(#b6b4b4));background:-moz-linear-gradient(top, #f9f9f9, #b6b4b4);background:-o-linear- gradient(top, #f9f9f9, #b6b4b4);background:linear-gradient(top, #f9f9f9, #b6b4b4);
http://www.w3.org/1999/xhtml" xml :lang="en">
< ;title>html5,css3 menu