css 自定义 ol/li 序号样式

ol {
  counter-reset: li;  // 创建计数器
}
ol li {
  position: relative;
  padding-left: 30px;
}
ol li::before {
  content: counter(li) ".";
  counter-increment: li;  // 递增计数器
  position: absolute;
  left: 0;
  font-size: 28px;
  color: rgba(0, 0, 0, .8);
}