@keyframes slide-background-x {
    from {
        background-position-x: 0;
    }

    to {
        background-position-x: -1096px;
    }
}

@keyframes ship-y {
    from {
        transform: translateY(10px);
    }

    to {
        transform: translateY(-10px);
    }
}

.strip {
    animation: slide-background-x 60s linear infinite;
}

.beetleship {
    animation: ship-y 1s linear infinite alternate;
}

.octopus {
    animation: ship-y 1.5s linear infinite alternate;
}

.item img {
    transition: opacity .5s ease;
}