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

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(to right in oklch longer hue, red, red);
    background-size: 300% 100%;
    animation: backgroundScroll 10s linear infinite;
}

@keyframes backgroundScroll {
  from { background-position: 0% 0%; }
  to { background-position: 300% 0%; }
}