.video {
    width: auto;
    height: auto;

    min-width: 100%;
    min-height: 100%;

    position: fixed;
    top: 50%;
    left: 50%;

    z-index: 1;

    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}