jellyfin-web/dashboard-ui/bower_components/emby-webcomponents/loading/loading.css

.docspinner {
    margin-top: -5vh;
    margin-left: -5vh;
    width: 10vh;
    height: 10vh;
    position: fixed;
    top: 50%;
    left: 50%;
    z-index: 9999999;
}

.loadingHide {
    display: none !important;
}