* {
    box-sizing: border-box;
    margin: 0; padding: 0;
    z-index: 3;
}

@keyframes backgroundScroll {
    from { background-position: 0px 0px; }
    to { background-position: 0px -10000px; }
}

body {
    position: relative;
    display: flex; flex-direction: column;
    align-items: center;
    min-height: 600vh; gap: 10px;

    animation: backgroundScroll 1500s ease infinite;
    background-color: rgb(0, 0, 0);
    background-image:
    linear-gradient(to bottom, white 1px, transparent 0px),
    linear-gradient(to right, white 1px, transparent 0px);
    background-repeat: repeat;
    background-size: 20px 20px;
}