#yith-wcwl-popup-message {
    background: white;
    border: 1px solid #CCC;
    border-radius: 5px;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    line-height: 50px;
    padding: 15px;
    position: fixed;
    text-align: center;
    top: 50%;
    left: 50%;
    z-index: 10000;
}