Css 脉冲效果

<div>
  <span style="--i:1;"></span>
  <span style="--i:2;"></span>
  <span style="--i:3;"></span>
  <span style="--i:4;"></span>
  <span style="--i:5;"></span>
  <span style="--i:6;"></span>
</div>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
 
body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #0a3643;
}
 
.pulse {
  position: relative;
  width: 200px;
  height: 200px;
  box-shadow: inset 0 0 40px #12b9ff,
  0 0 50px #12b9ff;
  border-radius: 50%;
  border: 1px solid #12b9ff;
  background: url(earth.png);
  background-size: cover;
  animation: animateEarth 10s linear infinite;
}
 
.pulse span {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: transparent;
  border: 1px solid #12b9ff;
  animation: animate 6s linear infinite;
  animation-delay: calc(var(--i) * -1s);
  border-radius: 50%;
}
 
@keyframs animate {
  0% {
    width: 200px;
    height: 200px;
    opacity: 1;
  }
 
  50% {
    opacity: 1;
  }
 
  100% {
    width: 600px;
    height: 600px;
    opacity: 0;
  }
}
 
@keyframs animateEarth {
  0% {
    background-position-x: 0px;
  }
 
  100% {
    background-position-x: 360px;
  }
}