:root {
    --horizontal-duration: 9.97s;
    --vertical-duration: 6.91s;
    --horizontal-delay: -2s;
    --vertical-delay: -1s;
}

.bounce img {
    position: fixed;
    animation: var(--horizontal-duration) linear var(--horizontal-delay) infinite forwards horizontal, var(--vertical-duration) linear var(--vertical-delay) infinite forwards vertical;
}

@keyframes horizontal {
    0% {
        left: 0%;
    }

    50% {
        left: calc(100% - 256px);
    }

    100% {
        left: 0%;
    }
}

@keyframes vertical {
    0% {
        top: 0%;
    }

    50% {
        top: calc(100% - 256px);
    }

    100% {
        top: 0%;
    }
}