body {
  background: #fff;
}

@media screen and (max-width: 480px) {
  .size {
    width: 100px;
  }
}

.center {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-right: -50%;
  transform: translate(-50%, -50%);
}

.logo_animation {
  animation: logo-pulse 3s infinite ease;
}

@keyframes logo-pulse {
  0% {
    opacity: 0.1;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0.1;
  }
}