#loading {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 10000;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.6);
}

#loading img {
    position: absolute;
    margin-left: -24px;
    margin-top: -24px;
    left: 50%;
    top: 50%;
    width: 48px;
    height: 48px;
}