水平CSS UL菜单

Question

由于某种原因，我的CSS样式UL菜单不会水平居中。创建它的CSS是：

#navigation { 
    width:79em; 
    height: 2em; 
    position: relative; 
    padding: .5em; 
    font-family: Verdana, Geneva, sans-serif; 
    text-transform: uppercase; 
    font-size: 1em; 
    background-color: #F5F5F5; 
    -webkit-border-radius: 3px; 
    -moz-border-radius: 3px; 
    border-radius: 3px; 
    -webkit-box-shadow: 0 0 1em 0 #333; 
    -moz-box-shadow: 0 0 1em 0 #333; 
    box-shadow: 0 .25em .3em -.055em #333; 
} 

#navigation ul { 
    text-align: center; 
    padding: 0; 
    margin: 0; 
    list-style: none; 
} 

#navigation li { 
    display: inline; 
    list-style: none; 
    display: block; 
    float: left; 
    width: 10em; 
    height: 2em; 
    text-align: center; 
    padding: .5em 0 0 0; 
    margin: 0; 
    border-left: .0625em solid #FFF; 
    border-right: .1em solid #CCC; 
    text-shadow: .0625em .0625em .0625em #ffffff; 
    filter: dropshadow(color=#ffffff, offx=1, offy=1); 
} 

Answer 1

添加

#navigation { 
... 
margin : 0 auto; 
}