<div class="loader"></div>

* {
  margin: 0;
  padding: 0;
}

body {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: #fff;
}
.loader {
  position: relative;
  width: 200px;
  height: 200px;
  border-radius: 10rem;
  border: 3px solid white;
  background: linear-gradient(#eb31b0, #e4c352, #7df8d6);
  box-shadow: 0px 0px 100px -50px black;
  animation: animate 1s linear infinite;
}

.loader::before {
  position: absolute;
  content: "";
  background: #fff;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 80%;
  height: 80%;
  border-radius: 10rem;
  border: 3px solid white;
  box-shadow: inset 0px 0px 100px -70px #111;
}

@keyframes animate {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}