.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(255, 255, 255, 0.9);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 9999;
}

.spinner {
  border: 4px solid rgba(0, 0, 0, 0.1);
  border-left-color: #3498db;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}