.wave{position:absolute;bottom:0;left:0;width:100%;height:100px;background:url(https://fartik.com/wp-content/uploads/2021/07/wave.png);background-size:1000px 100px;animation:animate 4s ease-in-out infinite;animation-delay:calc(var(--i) * 0.25s)}.wave#wave1{z-index:1000;opacity:1;background-position-x:400px}.wave#wave2{z-index:999;opacity:.5;background-position-x:300px}.wave#wave3{z-index:998;opacity:.2;background-position-x:200px}.wave#wave4{z-index:999;opacity:.7;background-position-x:100px}@keyframes animate{0%,100%{transform:translateY(0)}50%{transform:translateY(10px)}}