【css实现倒计时】

<div></div>
<style> @property --c {
    syntax: "<integer>";
    initial-value: 0;
    inherits: true;
  }
  
  @keyframes timer {
    from { --c: 10 }
    to   { --c: 0 }
  }
  
  :root { animation: timer 5s linear }

  div::after {
    counter-reset: c var(--c);
    content: counter(c, decimal-leading-zero);
  } </style>