#menu-background-image {
    height: 100%;
    width: 100%;

    background-image: url(/img/weed.png);

    position: absolute;
    left: 0px;
    top: 0px;
    z-index: 0;

    background-position: center 40%;
    background-size: 110vmax;
    opacity: 0.2;

    transition: opacity 800ms ease,
        background-size 800ms ease,
        background-position 800ms ease;
}