📋 倒计时嵌入生成

<!-- 假期日历倒计时组件 -->
<div id="holiday-calendar-countdown" style="font-family:system-ui,sans-serif;text-align:center;padding:20px;border:2px solid #ef4444;border-radius:12px;max-width:400px;margin:0 auto">
  <div style="font-size:18px;font-weight:bold;color:#ef4444;margin-bottom:12px">活动名称</div>
  <script>
    (function(){
      var target=new Date('').getTime();
      var el=document.getElementById('holiday-calendar-countdown');
      function update(){
        var now=new Date().getTime(),d=target-now;
        var days=Math.floor(d/864e00),hrs=Math.floor(d%864e00/36e5),min=Math.floor(d%36e5/6e4),sec=Math.floor(d%6e4/1e3);
        el.querySelector('.timer').innerHTML=days+'天 '+"+hrs+"时 "+min+"分 "+sec+"秒';
      }
      var timer=document.createElement('div');timer.className='timer';timer.style.fontSize='24px';timer.style.fontWeight='bold';timer.style.color='#ef4444';
      el.appendChild(timer);update();setInterval(update,1000);
    })();
  </script>
  <div style="margin-top:8px;font-size:11px;color:#999">由 <a href="https://holiday-calendar.cn" style="color:#ef4444">假期日历</a> 提供</div>
</div>