#preloader {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: #ffffff;
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 20000;
  transition: opacity 0.5s ease;
}
#preloader.preloader-hidden {
  opacity: 0;
  pointer-events: none;
  visibility: hidden;
}
.loader3d {
  width: 48px;
  height: 48px;
  border: 3px solid #f3f3f3;
  border-top: 3px solid #2962ff;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}