body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #0a0a0a;
  color: #fff;
}
button {
  margin: 10px;
  padding: 10px 20px;
  font-size: 16px;
  border-radius: 8px;
  border: none;
  background: #4cafef;
  color: white;
  cursor: pointer;
}
button:hover {
  background: #369cd6;
}
#loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  color: white;
  font-size: 20px;
}
.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid #fff;
  border-top: 4px solid #4cafef;
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: 20px;
}
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}