#scroll-progress-track {
  position: fixed;
  left: 0;
  right: 0;
  height: 4px;
  background: rgba(61, 69, 146, 0.15);
  border-radius: 999px;
  z-index: 9999;
  pointer-events: none;
  /* Hiệu ứng ẩn hiện mượt mà */
  transition: opacity 0.4s ease, visibility 0.4s ease, top 0.2s ease;
  opacity: 0;
  visibility: hidden;
}

#scroll-progress-bar {
  height: 100%;
  width: 0%;
  background: #3d4592;
  border-radius: 999px;
  transition: width 0.15s ease-out;
}

@media (max-width: 768px) {
  #scroll-progress-track {
    height: 3px;
  }
}