#loader {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 1050;
  width: 100vw;
  height: 100vh;
  background: white;
  display: flex;
  align-items: center;
  justify-content: center;
}
#loader_logo {
  width: 75%;
  max-width: 300px;
  animation-duration: 1.5s;
  animation-name: slidein;
  animation-iteration-count: infinite;
}
@keyframes slidein {
  0% { opacity: .3; }
  50% { opacity: 1; }
  100% { opacity: .3; }
}