label[for="conditions_to_approve[customer-comment]"]>div {
    display: none;
    padding: 10px 0;
}
label[for="conditions_to_approve[customer-comment]"] textarea::placeholder {
    color: #999!important;
}

input[id="conditions_to_approve[customer-comment]"]:checked + * + label > div {
    display:block;
}