#preloader {
  position: fixed;
  inset: 0;
  background: #343541;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.3s, visibility 0.3s;
}

#preloader.hidden {
  opacity: 0;
  visibility: hidden;
}

.preloader-spinner {
  width: 48px;
  height: 48px;
  border: 3px solid #40414f;
  border-top-color: #10a37f;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}