@media (max-device-width: 768px) {
    .bg {
        animation:slide 3s ease-in-out infinite alternate;
        background-image: linear-gradient(180deg, #09f 50%, #f4d7a7 50%);
        bottom:0;
        left:0;
        opacity: .5;
        position: fixed;
        right: 0;
        top: 0;
        z-index: -1;
    }

    .bg2 {
        animation-direction:alternate-reverse;
        animation-duration:4s;
    }

    .bg3 {
        animation-duration:5s;
    }
}

.content {
    background-color:rgba(255,255,255,.8);
    border-radius:.25em;
    box-shadow:0 0 .25em rgba(0,0,0,.25);
    box-sizing:border-box;
    left:50%;
    padding:10vmin;
    position:fixed;
    text-align:center;
    top:50%;
    transform:translate(-50%, -50%);
}
.container {}

@keyframes slide {
    0% {
        transform:translateY(-25%);
    }
    100% {
        transform:translateY(25%);
    }
}