.bubble {
    width: 69px;
    position: absolute;
    animation-name: goUp;
    animation-duration: 8s;
    animation-fill-mode: forwards;
}

@keyframes goUp {
    0% {
        transform: translateY(0);
    }
    100% {
        transform: translateY(-1000px);
    }
}

body {
    overflow: hidden;
}