/* Preloader nền */
#preloader {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); /* Gradient phù hợp với theme */
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 99999; /* Cao hơn để đảm bảo hiển thị trên cùng */
  color: white;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  transition: opacity 0.8s ease, visibility 0.8s ease;
}

#preloader.fade-out {
  opacity: 0;
  visibility: hidden;
}

/* Vòng tròn xoay */
.loader {
  border: 4px solid rgba(255, 255, 255, 0.2);
  border-top: 4px solid #ffffff;
  border-radius: 50%;
  width: 60px;
  height: 60px;
  animation: spin 1s linear infinite;
  margin-bottom: 20px;
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

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

#preloader p {
  font-size: 18px;
  font-weight: 500;
  margin: 0;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  letter-spacing: 1px;
}

/* Thêm hiệu ứng pulse cho text */
#preloader p {
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

/* Loading dots animation */
.loading-dots {
  display: inline-block;
  margin-left: 5px;
}

.loading-dots::after {
  content: '';
  animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
  0%, 20% { content: ''; }
  40% { content: '.'; }
  60% { content: '..'; }
  80%, 100% { content: '...'; }
}

/* Responsive */
@media (max-width: 768px) {
  .loader {
    width: 50px;
    height: 50px;
    border-width: 3px;
  }
  
  #preloader p {
    font-size: 16px;
  }
}