纯css做幻灯片效果

css3里面有一个@keyframes动画功能。
w3c上面的例子：
可以使用它来做一个幻灯片效果。
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>纯CSS做幻灯片</title>
</head>
<style>
    @keyframes slide {
        0% {
            background: url('https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=4229874093,2188481433&fm=26&gp=0.jpg') 0px 0px
        }
        25% {
            background: url('https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1548875514394&di=62dd50a1da7183efb48c88980269b64c&imgtype=jpg&src=http%3A%2F%2Fimg3.imgtn.bdimg.com%2Fit%2Fu%3D3037014303%2C3112421008%26fm%3D214%26gp%3D0.jpg') 0px 0px;
        }
        50% {
            background: url('https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1548875548425&di=1bc4e9b80d56d1f10c0e4d326dfa505a&imgtype=jpg&src=http%3A%2F%2Fimg1.imgtn.bdimg.com%2Fit%2Fu%3D1161267701%2C3620139336%26fm%3D214%26gp%3D0.jpg') 0px 0px;
        }
        100% {
            background: url('https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1548875490599&di=8c072d8773a04366464cac34db72f50e&imgtype=0&src=http%3A%2F%2Fp1.so.qhmsg.com%2Ft015663aba355e338c6.png') 0px 0px;

        }
    }

    div {
         400px;
        height: 400px;
        animation: slide 14s infinite;
    }
</style>

<body>
    <div>

    </div>

</body>

</html>