.repair-article {
    margin: 20px 0 20px;
}
.repair-article .serial-number {
    display: none;
    margin: 10px 0 0px;
}
.repair-article .serial-number .field-txt{
    display: inline-block;
}
.repair-article .valid-field {
    color: red;
}
.repair-article .valid-field input{
    border-color: red;
}