애니메이션

---

 

 

 

 

HTML

<div></div>

 

 

CSS

*, *::before, *::after {
  box-sizing: bolder-box;
}
html,body {
  height: 100%;
}
body {
  display: grid;
  align-items: center;
  justify-content: center;
  margin: 0;
  background-color: #000;
}
div {
  width: 300px;
  height: 300px;
  border-radius: 50%;
  box-shadow: 0 0 20px #fff,
              -20px 0 80px #f0f,
              20px 0 80px #0ff,
              inset 0 0 50px #f0f,
              inset -50px 0 80px #0ff,
              inset 50px 0 300px #f0f,
              inset -50px 0 300px #0ff;
  animation: plusate 3s linear infinite;
}
@keyframes plusate {
  50% {
        box-shadow:
          0 0 20px #fff,
          20px 0 80px #f0f,
          -20px 0 80px #0ff,
          inset 0 0 50px #fff,
          inset -50px 0 80px #f0f,
          inset 50px 0 80px #0ff,
          inset -50px 0 300px #f0f,
          inset 50px 0 300px #0ff;
  }
}