.loading { background-color: rgba(0, 0, 0, 0.5); position: fixed; top: 0; left: 0; width: 100%; height: 100%; z-index: 99; }
.loading:before { content: ""; position: absolute; width: 4em; height: 4em; border: solid rgba(255, 255, 255, 0.2) 0.6em; border-right-color: #fff; -webkit-border-radius: 50%; -moz-border-radius: 50%; -ms-border-radius: 50%; border-radius: 50%; top: 50%; left: 50%; margin: -2.3em 0 0 -2.3em; -webkit-animation: loop 1s infinite linear; -moz-animation: loop 1s infinite linear; -ms-animation: loop 1s infinite linear; animation: loop 1s infinite linear; }

@-webkit-keyframes loop {
    to { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); transform: rotate(360deg); }
}

@-moz-keyframes loop {
    to { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); transform: rotate(360deg); }
}

@-ms-keyframes loop {
    to { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); transform: rotate(360deg); }
}

@keyframes loop {
    to { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); transform: rotate(360deg); }
}