#field { margin-left: .5em; float: left; }
#field, label { float: left; font-family: Arial, Helvetica, sans-serif; font-size: small; }
br { clear: both; }
input { border: 1px solid black; margin-bottom: .5em;  }
input.error { border: 1px solid red; }

label.error {
    background: url('images/unchecked.png') no-repeat;
    padding-left: 16px;
    margin-left: .3em;
    color: #f00;
}
label.valid {
    background: url('images/checked.png') no-repeat;
    display: block;
    width: 16px;
    height: 16px;
}