*{
  box-sizing:border-box;
  margin:0;
  padding:0;
}
html,
body {
  height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  background-color: #e8e8e8;
  font-family:arial;
}
.loader {
  width: 48px;
  height: 48px;
  background: #353535;
  display: block;
  margin: 20px auto;
  position: relative;
  box-sizing: border-box;
  animation: rotationBack 1s ease-in-out infinite reverse;
}

.loader::before {
  content: '';
  box-sizing: border-box;
  left: 0;
  top: 0;
  transform: rotate(45deg);
  position: absolute;
  width: 48px;
  height: 48px;
  background: #2e2e2e;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
}

.loader::after {
  content: '';
  box-sizing: border-box;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  position: absolute;
  left: 50%;
  top: 50%;
  background: rgb(0, 0, 0);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
}

@keyframes rotationBack {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(-360deg);
  }
}