Ci sono già i div:
#form-login-username, #form-login-password, #form-login-remember {
float:left;
padding:15px;
font-family: 'Open Sans',sans-serif;
}
.button {
margin-top:15px;
}
.userdata {
border:0;
}
#login-form li {
padding-left:15px;
line-height:19px;
font-family: 'Open Sans',sans-serif;
font-size:14px;
}
per esempio...