css如何实现幻灯片效果

<section id=box>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>1</li>
  </ul>
</section>

<style>
    * {
      margin: 0;
      padding: 0;
      font-family: 微软雅黑;
      list-style: none;
    }
    #box{
        width:400px;
        height:200px;
        border: 1px solid #000;
        margin: 50px auto;
        overflow: hidden;
    }
    ul{
      width: 2000px;
      animation: dh 10s infinite ease;
    }
    ul li{
      width:400px;
      height:200px;
      float: left;
    }
    ul li:nth-child(1){
      background:#4b86db;
    }
    ul li:nth-child(2){
      background:#ff9999;
    }
    ul li:nth-child(3){
      background:olivedrab;
    }
    ul li:nth-child(4){
      background:skyblue;
    }
    ul li:nth-child(5){
      background:#4b86db;
    }
 
@keyframes dh {
      0%{transform: translateX(0)}
      25%{transform: translateX(-400px)}
      50%{transform: translateX(-800px)}
      75%{transform: translateX(-1200px)}
      100%{transform: translateX(-1600px)}
}
  </style>