body {
  padding: 0;
  margin: 0;
}

.preloader {
  position: "fixed";
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.preloader-element {
  width: 32px;
  height: 32px;
  position: relative;
  border-radius: 50%;
  color: #01c864;
  animation: fill 1s ease-in infinite alternate;
}
.preloader-element::before,
.preloader-element::after {
  content: "";
  position: absolute;
  height: 100%;
  width: 100%;
  border-radius: 50%;
  left: 48px;
  top: 0;
  animation: fill 0.9s ease-in infinite alternate;
}

.preloader-element::after {
  left: auto;
  right: 48px;
  animation-duration: 1.1s;
}

@keyframes fill {
  0% {
    box-shadow: 0 0 0 2px inset;
  }
  100% {
    box-shadow: 0 0 0 10px inset;
  }
}