*{margin:0;padding:0;border:0;}

#nav {
font-size:12px;
     line-height: 23px;  list-style-type: none; background:#ffffff;
}
.c a{text-decoration:none;}
#nav a {
    display: block; width: 90px; text-align:center;
}

#nav a:link  {
    color:#ffffff; text-decoration:none;
}
#nav a:visited  {
    color:#ffffff;text-decoration:none;
}
#nav a:hover  {
    color:#FFF;text-decoration:none;font-weight:bold;
}

#nav li {
    float: left; width: 90px; background:#CCC;
	
}
#nav li a:hover{
    
}
#nav li ul {
 border : 1px solid #41B089;
    line-height: 24px;  list-style-type: none;text-align:center;
    left: -999em; width: 90px; position: absolute; 
filter : progid:DXImageTransform.Microsoft.DropShadow(color=#FF404040,offX=3,offY=3,positives=true) alpha(opacity=85);
}
#nav li ul li{
    
    float: left; width: 90px;
    background: #ffffff; 
	
}

<!--控制下拉宽　控制下拉字体是否居中　　控制字体离最左面的距离　　　　　-->
#nav li ul a{
    display: block; width: 90px;text-align:center;padding-left:1px;
}

#nav li ul a:link  {
    color:#000000; text-decoration:none;
}
#nav li ul a:visited  {
    color:#000000;text-decoration:none;
}
#nav li ul a:hover  {
    color:#F3F3F3;text-decoration:none;font-weight:normal;
    background:#41B089;
}

#nav li:hover ul {
    left: auto;
}
#nav li.sfhover ul {
    left: auto;
}