.mobilewarning {
    position: block;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    z-index: 10000;
}

.middle {
    position: relative;
    top: 30%;
    text-align: center;
    font-size: 2em;
    color: white;
    font-family: Tahoma, Verdana, sans-serif;
}


.hidden {
    display: none;
}

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

    70% {
        transform: rotate(-90deg);
    }

    100% {
        transform: rotate(-90deg);
    }
}

.mobilewarning img {
    height: 200px;
    animation: rotate-device 3s ease-in-out infinite;
}