/* 🩵 Overlay loading đẹp & mượt */
.overlay-loading {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.55); /* nền mờ */
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  z-index: 2000;
  opacity: 0;
  pointer-events: none;
  transform: scale(1.05);
  transition: all 0.35s ease;
}

/* Khi overlay hiển thị */
.overlay-loading.show {
  opacity: 1;
  pointer-events: auto;
  transform: scale(1);
}

/* Spinner đẹp hơn một chút */
.overlay-loading .spinner-border {
  width: 3rem;
  height: 3rem;
  animation: spin 1s linear infinite;
  filter: drop-shadow(0 0 6px rgba(255,255,255,0.6));
}

/* Hiệu ứng xoay mượt */
@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* Dòng chữ nhẹ nhàng */
#overlayMessage {
  font-size: 1.1rem;
  font-weight: 500;
  text-shadow: 0 0 6px rgba(255, 255, 255, 0.3);
  animation: fadeText 1s ease infinite alternate;
}

@keyframes fadeText {
  from { opacity: 0.7; }
  to { opacity: 1; }
}