#billing_form input, #billing_form select {
    width: calc(50% - 50px);
}

#billing_form {
    margin-bottom: 50px;
}

.billing_title {
    width: calc(100% - 100px);
    margin: auto;
    margin-top: 20px;
    margin-bottom: 20px;
}

#billing_address_title {
    margin-top: 80px;
}

.field_error {
    color: red;
    text-align: center;
    padding-bottom: 30px;
}

#container_warning_invoice {
    text-align: center;
    font-weight: lighter;
    font-family: SourceSansPro;
    font-style: italic;
    color: red;
    font-size: 17px;
}

@media only screen and (max-width: 768px) {
    #container_warning_invoice {
        width: 90%;
        margin: auto;
    }
}