.loader {
    border: 16px solid #f3f3f3;
    border-radius: 50%;
    border-top: 16px solid #3498db;
    width: 120px;
    height: 120px;
    -webkit-animation: spin 2s linear infinite; /* Safari */
    animation: spin 2s linear infinite;
    position: fixed;
    left: 50%;
    top: 50%;
    z-index: 1;
    margin: -77px 0 0 -77px;
}

/* Safari */
@-webkit-keyframes spin {
    0% {
        -webkit-transform: rotate(0deg);
    }

    100% {
        -webkit-transform: rotate(360deg);
    }
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}


#overlay {
    position: fixed;
    display: none;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255,255,255,0.7);
    z-index: 2;
    cursor: pointer;
}