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                <div class="sky sky1">
  <span class="one"></span>
<div class="sky sky2">
  <span class="two"></span>


  margin: 0;
  padding: 0;
  /* 设置所有元素的width、height包括内边距、边框、内容区 */
  box-sizing: border-box;
/* 设置body的子元素水平垂直居中 */
  height: 100vh;
  display: flex;
  justify-content: space-around;
  align-items: center;
  background-color: black;
  width: 50vh;
  height: 50vh;
  /* 超出sky的部分隐藏  
  border: 1px solid white;  */
  overflow: hidden;
/* 设置sky1的子元素全部倾斜45度 */
.sky1 > * {
  transform: rotate(45deg);

/* 流星的样式 */
.sky .one{
  display: block;
  width: 10vh;
  border-width: 1px 0 0 0;
  border-style: solid;
  border-color: white black black black;
  margin-top: -6vh;
  margin-left: -6vh;
  animation: shooting 1s linear 1s infinite;
@keyframes shooting{
    margin: 50vh;
/* 第二颗流星:改进版的shootingStar */ 
/* 设置尾巴 */
  position: relative;
  display: inline-block;
  width: 80px;
  border-radius: 50% 0 0 50%;
  border-width: 0.5px;
  border-style: solid;
  border-color: #F9FBE7;
  /* 增加一点光辉 
  box-shadow: 0 0 2px white;
  margin-top: 200px;
  margin-left: -100px;
  animation: shooting2 1s linear 1s infinite;
/* 利用伪元素设置头部 */
  border-radius: 50%;
  border: 2px solid white;
  background-color: white;
  position: absolute;
  top: -1.4px;
  right: -1.5px;
@keyframes shooting2{
    margin-top: 200px;
    margin-left: 250px;