#alert_shade {
    background: none repeat scroll 0 0 rgba(0, 0, 0, 0.5);
    bottom: 0;
    display: none;
    left: 0;
    position: fixed;
    right: 0;
    top: 0;
    width: 100%;
    z-index: 100;
}
#alert {
    display: none;
}