.center {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%); /* for IE 9 */
    -webkit-transform: translate(-50%, -50%); /* for Safari */
}


@keyframes spinner-line-fade-more {
    0%, 100% {
        opacity: 0; /* minimum opacity */
    }

    1% {
        opacity: 1;
    }
}

@keyframes spinner-line-fade-quick {
    0%, 39%, 100% {
        opacity: 0.25; /* minimum opacity */
    }

    40% {
        opacity: 1;
    }
}

@keyframes spinner-line-fade-default {
    0%, 100% {
        opacity: 0.22; /* minimum opacity */
    }

    1% {
        opacity: 1;
    }
}

@keyframes spinner-line-shrink {
    0%, 25%, 100% {
        /* minimum scale and opacity */
        transform: scale(0.5);
        opacity: 0.25;
    }

    26% {
        transform: scale(1);
        opacity: 1;
    }
}