/* 裁剪放大的图片,不遮挡下方内容 */
#page-header {
  overflow: hidden !important;
}

.banner-slide {
  position: absolute;
  top: -40%;              /* 上下各留 40% 缓冲,给平移留跑道 */
  left: 0;
  width: 100%;
  height: 180%;
  opacity: 0;
  z-index: 0;
  pointer-events: none !important;
  /* 外层只负责淡入淡出(不再带 scale) */
  animation: bannerFade 15s infinite;
}
.banner-slide-inner {
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  /* 内层专门做缓慢缩放 */
  animation: kenburns 5s ease-in-out infinite alternate;
}
@keyframes bannerFade {
  0%   { opacity: 0; }
  3%   { opacity: 1; }
  33%  { opacity: 1; }
  38%  { opacity: 0; }
  100% { opacity: 0; }
}
@keyframes kenburns {
  from { transform: scale(1); }
  to   { transform: scale(1.08); }
}
/* 文字层在图片之上 */
#site-info {
  position: relative;
  z-index: 2;
}

/* 半透明遮罩:加深版,保证文字清晰 */
.banner-overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 1;
  pointer-events: none !important;
  background: linear-gradient(rgba(0,0,0,0.55), rgba(0,0,0,0.35));
}

/* 向下滚动按钮置于最上层 */
#scroll-down {
  position: relative;
  z-index: 3 !important;
}