@keyframes spin {
    to {
        transform: rotate(1turn);
    }
}

.spinner {
    position: absolute;
    display: none;
    width: 5em;
    height: 5em;
    font-size: 4px;
    text-indent: 999em;
    overflow: hidden;
    animation: spin 1s infinite steps(8);
}

.spinner:before,
.spinner:after,
.spinner > div:before,
.spinner > div:after {
    content: '';
    position: absolute;
    top: 0;
    left: 2.25em;
    width: .5em;
    height: 1.5em;
    border-radius: .2em;
    background: #eee;
    box-shadow: 0 3.5em #eee;
    transform-origin: 50% 2.5em;
}

.spinner:before {
    background: #555;
}

.spinner:after {
    transform: rotate(-45deg);
    background: #777;
}

.spinner > div:before {
    transform: rotate(-90deg);
    background: #999;
}

.spinner > div:after {
    transform: rotate(-135deg);
    background: #bbb;
}

.rotate {
    animation: spin 2s linear infinite;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}