body { background: #111; display: grid; place-items: center; min-height: 100vh; }
.shimmer {
    font: 700 3rem system-ui;
    background: linear-gradient(90deg, #777, #fff, #777, #fff, #777) 0 / 200% auto;
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    animation: slide 2.5s linear infinite;
}
@keyframes slide { to { background-position: -200% center; } }