.overlay{
    display: table;
    position: fixed;
    height: 100%;
    width: 100%;
    background: rgba(255,255,255,.7);
    z-index: 9999;
    top: 0;
    left: 0;
}

.overlay > .overlay-align{
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}

.overlay > .overlay-align > .overlay-wrapper {
    display: inline-block;
}