#login 
{
    margin: 3em auto auto;
    width: 670px;
    padding: auto;
}

#nav
{
    margin:0;
    text-align:center;
}

.login form
{
    margin:0;
    margin-top:20px;
    padding:0;
    background-color:#FFFFFF;
}
form .submit 
{
    float:none;
}