*{
margin:0px;
padding:0px;
}
#header {
margin:auto;
width:500px;
front-family:Arial,Helvetica,sans-serif;
}
ul,ol{
list-style:none;
}
.nav > li{
float:left;
}
.nav li a{
bacground-color:#000;
color:#fff;
text-decoration:none;
padding:10px 12px;
display:block;
}
.nav li a:hover{
bacground-color:#434343;
}
.nav li ul{
display:none;
posiion:absolute;
min-width:140px;
}
.nav li:hover > ul {
display:block;
}
.nav li ul li{
position:relative;
}
.nav li ul li ul{
rigth:-140px;
top:0px;
}