html,
body {
  margin: 0;
  background-color: #000000;
}
.container {
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  flex: auto;
  flex-direction: column;
}
@keyframes breathe {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.55;
  }
}
.indicator {
  width: 72px;
  height: 72px;
  animation: breathe 1.8s ease-in-out infinite;
}