css实现云层效果


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>云彩</title>
    <style>
    
        * {
            margin:0;
            padding:0;
        }
        
        html,body {
            height:100%;
        }
        
        section {
            width: 100%;
            height: 100%;
            background: #007fd5;
            overflow: hidden;
            display: block;
            position: relative;
            animation: bg 20s linear infinite;
        }

        section div {
            width: 300%;
            height:100%;
            position: absolute;
            left:0;
            top:0;
        }

        section div:nth-child(1) {
            background:url(./images/cloud_one.png);
            animation: play 50s linear infinite;
        }
        section div:nth-child(2) {
            background:url(./images/cloud_two.png);
            animation: play 75s linear infinite;
        }
        section div:nth-child(3) {
            background:url(./images/cloud_three.png);
            animation: play 100s linear infinite;
        }

        @keyframes bg {
            0% {
                background:#007fd5;
            }
            50% {
                background: #000;
            }
            100% {
                background: #007fd5;
            }
        }

        @keyframes play {
            0% {
                left:0;
            }
            100% {
                left:-200%;
            }
        }
    </style>
</head>
<body>
    <section>
        <div></div>
        <div></div>
        <div></div>
    </section>
</body>
</html>