适用浏览器:IE8、360、FireFox、Chrome、Safari、Opera、傲游、搜狗、世界之窗.
The item width of this navigation gets calculated automatically, all you need to provide is the width of the surrounding container.
The container has a padding of 3px, so when inserting a width, consider the 6 additional pixels from the sides.
The absolute height of the menu is 36px (30px + 3px padding from top and bottom).