html,
body {
  height: 100%;
  margin: 0;
  overflow: hidden;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
}

.logo {
  animation: scale 2s infinite ease;
  border-radius: 50%;
  width: 150px;
}


@keyframes scale {
  0% {
    opacity: 0;
    width: 150px;
  }
  50% {
    box-shadow: 0 0 10px rgba(0,0,0,.2);
    opacity: 1;
    width: 250px;
  }
  100% {
    opacity: 0;
    width: 150px
  }
}