#loading {
    display: none;
    position: fixed;
    top: 0;
    background: rgba(128,128,128, .1);
    left: 0;
    bottom: 0;
    right: 0;
}

#loading i {
    font-size: 100px;
    position: absolute;
    left: 50%;
    top: 50%;
    margin-top: -50px;
    margin-left: -50px;
}