为什么我的怎么改导航栏都不对？
.wrapper{
width:1000px;
margin:0px auto;
}
.logo{
height:80px;
background-color:#FFF;
}
.logo_left{
width:200px;
float:left;
}
.logo_right{
width:300px;
float:right;
height:28px;
margin-top:30px;
}
.logo_right img
{
vertical-align:middle;
margin-right:5px;
}
.nav
{
height:40px;
}
.nav_left
{
width:10px;
height:40px;
background:url(../images/nav_left.jpg) no-repeat;
float:left;
}
.nav_mid
{
width:980px;
height:40px;
background:url(../images/nav_bg.jpg) repeat-x;
float:left;
}
.nav_right
{
width:10px;
height:40px;
background:url(../images/nav_right.jpg) no-repeat;
float:left;
}
.nav_mid li
{
float:left;
list-style:none;
}
