.hidden {
  display: none;
}

.block {
  display: block;
}

/* Loader styles */
.loader {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  z-index: 1000;
}

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

.loader .text {
  margin-top: 10px;
  font-size: 16px;
}

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

/* Responsive button styles */
@media (min-width: 640px) {
  #buttons {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  #buttons {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}