.gform_wrapper .form > * {
    margin-left: auto;
    margin-right: auto;
}
.gfield.donation_buttons input[type="radio"]:checked + label {
    color: #fff;
    background: #003a96;
}
.gfield.donation_buttons input[type="radio"] + label {
    color: #003a96;
    border-color: #003a96;
}