onionmap.css

#map {
    position: relative;
    height: 500px;
}
#map.loading {}
#map.loading::before {
    content: " ";
    display: block;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(0, 0, 0, 0.2);
    z-index: 1;
}

#map.loading::after {
    content: " ";
    display: block;
    position: absolute;
    z-index: 2;
    top: 50%;
    left: 50%;
    margin: -5.5em 0 0 -5.5em;
    font-size: 10px;
    text-indent: -9999em;
    width: 11em;
    height: 11em;
    border-radius: 50%;
    background: #fff;
    background: -moz-linear-gradient(left, #fff 10%, rgba(255, 255, 255, 0) 42%);
    background: -webkit-linear-gradient(left, #fff 10%, rgba(255, 255, 255, 0) 42%);
    background: -o-linear-gradient(left, #ffffff 10%, rgba(255, 255, 255, 0) 42%);
    background: -ms-linear-gradient(left, #ffffff 10%, rgba(255, 255, 255, 0) 42%);
    background: linear-gradient(to right, #ffffff 10%, rgba(255, 255, 255, 0) 42%);
    -webkit-animation: loading 1.4s infinite linear;
    animation: loading 1.4s infinite linear;
    -webkit-transform: translateZ(0);
    -ms-transform: translateZ(0);
    transform: translateZ(0);
}

@-webkit-keyframes loading {
    0% {
        -webkit-transform: rotate(0deg);
        transform: rotate(0deg);
    }
    100% {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}
@keyframes loading {
    0% {
        -webkit-transform: rotate(0deg);
        transform: rotate(0deg);
    }
    100% {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}