10 个 GitHub 上超火的 CSS 奇技淫巧项目，找到写 CSS 的灵感！

<style>
  main {
    width: 100%; height: 229px;
    display: flex;
    justify-content: center;
    align-items: center;
  }
  span {
    display: inline-block;
    width: 21ch;
    font: bold 200% Consolas, Monaco, monospace;   /*等宽字体*/
    overflow: hidden;
    white-space: nowrap;
    font-weight: 500;
    border-right: 1px solid transparent;
    animation: typing 10s steps(21), caret .5s steps(1) infinite;
  }
  @keyframes typing{
    from {
        width: 0;
    }
  }
  @keyframes caret{
    50% { border-right-color: currentColor}
  }
</style>
<template>
  <main class="main">
    <span>前端GitHub</span>
  </main>
</template>
<script>
</script>
https://lhammer.cn/You-need-to-know-css/#/zh-cn/

<div class="poptip btn" aria-controls="弹出气泡">poptip</div>

$poptipBg: #30363d;
$color: #fff;
$triangle: 8px;
$distance: -12px;
.poptip {
  position: relative;
  z-index: 101;
  &::before,
  &::after {
    visibility: hidden;
    opacity: 0;
    transform: translate3d(0, 0, 0);
    transition: all 0.3s ease 0.2s;
    box-sizing: border-box;
  }
  &::before {
    content: "";
    position: absolute;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: $triangle $triangle 0 $triangle;
    border-color: $poptipBg transparent transparent transparent;
    left: calc(50% - #{$triangle});
    top: 0px;
    transform: translateX(0%) translateY($distance);
  }
  &::after {
    font-size: 14px;
    color: $color;
    content: attr(aria-controls);
    position: absolute;
    padding: 6px 12px;
    white-space: nowrap;
    z-index: -1;
    left: 50%;
    bottom: 100%;
    transform: translateX(-50%) translateY($distance);
    background: $poptipBg;
    line-height: 1;
    border-radius: 2px;
  }
  &:hover::before,
  &:hover::after {
    visibility: visible;
    opacity: 1;
  }
}
.btn {
  min-width: 100px;
  line-height: 1.5;
  padding: 5px 10px;
  color: #fff;
  background: #00adb5;
  border-radius: 4px;
  text-align: center;
  cursor: pointer;
}