#root {
    height: 100%;
}

#mask {
    z-index: 1;
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-align: center;
    align-items: center;
}

#mask-pane {
    margin: auto;
    position: relative;
    z-index: 1;
}

#mask-pane-content {
    width: 100px;
}