.wpcf7-form .wpcf7-response-output.wpcf7-validation-errors {
    color: #FFFFFF;
    background-color: #9099a2;
    border: 0;
    padding: 10px;
}
.wpcf7-form .wpcf7-response-output.wpcf7-mail-sent-ok {
    color: #FFFFFF;
    background-color: #9099a2;
    border: 0;
    padding: 10px;
}