/* ============================================================
   index.css — 南仁东线上成果展 · 页面专属样式
   ============================================================ */

/* ---- 阅读进度条 ---- */
#progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background-color: #b8941a;
  z-index: 9999;
  transition: width 0.1s linear;
}

/* ============================================================
   导航
   ============================================================ */
.site-nav {
  position: fixed;
  top: 3px;
  left: 0;
  right: 0;
  background: #ffffff;
  border-bottom: 1px solid #e4ddd4;
  z-index: 500;
  height: 60px;
}

.site-nav .nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 48px;
}

.nav-logo {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: #1b3252;
}

.nav-logo span {
  color: #b8941a;
}

.nav-links {
  display: flex;
  gap: 40px;
  align-items: center;
}

.nav-links li a {
  font-size: 14px;
  letter-spacing: 0.06em;
  color: #444444;
  padding-bottom: 2px;
  border-bottom: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}

.nav-hamburger {
  display: none;
}

.nav-links li a:hover,
.nav-links li a.active {
  color: #1b3252;
  border-bottom-color: #b8941a;
}

/* ============================================================
   Hero 区
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #faf7f2;
  overflow: hidden;
  padding-top: 63px; /* nav height */
}

/* 背景装饰：散点 (box-shadow 模拟) */
.hero-dots {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  pointer-events: none;
}

.hero-dots::before {
  content: '';
  position: absolute;
  width: 2px;
  height: 2px;
  border-radius: 50%;
  background: #c8bfb0;
  box-shadow:
    80px   60px 0 1px #c8bfb0,
    180px 140px 0 1px #c8bfb0,
    320px  40px 0 1px #d0c5b5,
    500px 200px 0 1px #c8bfb0,
    680px  80px 0 1px #d0c5b5,
    820px 160px 0 1px #c8bfb0,
    960px  50px 0 1px #c8bfb0,
   1100px 180px 0 1px #d0c5b5,
   1260px  90px 0 1px #c8bfb0,
   1380px 220px 0 1px #c8bfb0,
    140px 320px 0 1px #d0c5b5,
    280px 480px 0 1px #c8bfb0,
    440px 380px 0 1px #c8bfb0,
    600px 560px 0 1px #d0c5b5,
    740px 420px 0 1px #c8bfb0,
    900px 300px 0 1px #c8bfb0,
   1050px 500px 0 1px #d0c5b5,
   1200px 360px 0 1px #c8bfb0,
   1350px 460px 0 1px #c8bfb0,
    60px  600px 0 1px #d0c5b5,
    220px 700px 0 1px #c8bfb0,
    380px 640px 0 1px #c8bfb0,
    560px 760px 0 1px #d0c5b5,
    700px 680px 0 1px #c8bfb0,
    860px 720px 0 1px #c8bfb0,
   1020px 620px 0 1px #d0c5b5,
   1180px 780px 0 1px #c8bfb0,
   1320px 700px 0 1px #c8bfb0;
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 0 auto;
  padding: 80px 48px;
  text-align: center;
}

.hero-eyebrow {
  font-size: 13px;
  letter-spacing: 0.22em;
  color: #b8941a;
  text-transform: uppercase;
  margin-bottom: 28px;
}

.hero-name {
  font-size: 120px;
  font-weight: 900;
  letter-spacing: 0.12em;
  color: #1b3252;
  line-height: 1;
  margin-bottom: 24px;
  font-family: Georgia, "STSong", "SimSun", "Source Han Serif SC", serif;
}

.hero-dates {
  font-size: 18px;
  letter-spacing: 0.18em;
  color: #888888;
  margin-bottom: 28px;
  font-family: Georgia, serif;
}

.hero-rule {
  width: 60px;
  height: 3px;
  background: #b8941a;
  margin: 0 auto 32px;
}

.hero-subtitle {
  font-size: 15px;
  letter-spacing: 0.14em;
  color: #555555;
  margin-bottom: 48px;
  line-height: 1.8;
}

.hero-subtitle span {
  display: inline-block;
  margin: 0 12px;
}

.hero-subtitle .sep {
  color: #b8941a;
  margin: 0 4px;
}

.hero-quote {
  font-size: 22px;
  font-style: italic;
  font-family: Georgia, "STSong", serif;
  color: #1b3252;
  line-height: 1.7;
  border-left: 3px solid #b8941a;
  padding-left: 24px;
  text-align: left;
  max-width: 560px;
  margin: 0 auto 56px;
}

.hero-scroll {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: #aaaaaa;
  font-size: 12px;
  letter-spacing: 0.14em;
}

.hero-scroll-arrow {
  width: 20px;
  height: 20px;
  border-right: 2px solid #aaaaaa;
  border-bottom: 2px solid #aaaaaa;
  transform: rotate(45deg);
  animation: bounce 1.6s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: rotate(45deg) translateY(0); }
  50%       { transform: rotate(45deg) translateY(6px); }
}

/* ============================================================
   统计标语带
   ============================================================ */
.stats-band {
  background: #1b3252;
  padding: 0;
}

.stats-band-inner {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  max-width: 1200px;
  margin: 0 auto;
}

.stat-block {
  padding: 36px 40px;
  border-right: 1px solid rgba(255, 255, 255, 0.12);
  text-align: center;
}

.stat-block:last-child {
  border-right: none;
}

.stat-num {
  display: block;
  font-size: 42px;
  font-weight: 900;
  color: #c8a83a;
  line-height: 1;
  margin-bottom: 8px;
  font-family: Georgia, serif;
  letter-spacing: 0.04em;
}

.stat-label {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.72);
  letter-spacing: 0.12em;
  line-height: 1.5;
}

/* ============================================================
   时间轴
   ============================================================ */

/* 整体区域：暖米色底，顶部海军蓝色条 */
.timeline-section {
  background: #f4f0e8;
  padding: 0;
  border-top: 3px solid #1b3252;
  overflow: hidden;
}

/* 横向滚动容器 */
.timeline-scroll {
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: #c8bfb0 transparent;
}

.timeline-scroll::-webkit-scrollbar {
  height: 3px;
}

.timeline-scroll::-webkit-scrollbar-thumb {
  background: #c8bfb0;
  border-radius: 2px;
}

/* 轨道：两端留白，定位连线 */
.timeline-track {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 48px 80px 52px;
  position: relative;
}

/*
  连线精确对齐圆点中心：
    track padding-top = 48px
    year: 16px × line-height 1.2 ≈ 19px  + margin-bottom 14px = 33px
    dot center (12px dot): 33 + 6 = 39px
    line top = 48 + 39 = 87px
*/
.timeline-track::before {
  content: '';
  position: absolute;
  top: 87px;
  left: 0;
  right: 0;
  height: 1px;
  background: #c8bfb0;
}

/* 单个节点 */
.tl-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 148px;
  padding: 0 12px;
  position: relative;
}

/* 年份标签 */
.tl-year {
  font-size: 16px;
  font-weight: 700;
  color: #1b3252;
  margin-bottom: 14px;
  font-family: Georgia, serif;
  letter-spacing: 0.06em;
  line-height: 1.2; /* 16 × 1.2 = 19.2px — 计算精度关键 */
  text-align: center;
}

/* 圆点：统一 12×12，避免不同尺寸导致错位 */
.tl-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #f4f0e8;
  border: 2px solid #b0a898;
  flex-shrink: 0;
  z-index: 1;
  transition: transform 0.2s;
}

.tl-item:hover .tl-dot {
  transform: scale(1.3);
}

/* 高亮节点：金色填充，同尺寸保持对齐 */
.tl-item--highlight .tl-dot {
  background: #b8941a;
  border-color: #b8941a;
  width: 12px;
  height: 12px;
  box-shadow: 0 0 0 4px rgba(184, 148, 26, 0.18);
}

.tl-item--highlight .tl-year {
  color: #b8941a;
}

/* 事件文字：紧凑、低对比 */
.tl-text {
  margin-top: 14px;
  font-size: 11px;
  color: #999999;
  text-align: center;
  line-height: 1.6;
  max-width: 110px;
  letter-spacing: 0.04em;
}

.tl-item--highlight .tl-text {
  color: #666666;
}

/* ============================================================
   章节通用
   ============================================================ */
.page-section {
  padding: 96px 0;
}

.page-section--alt {
  background: #f4f0e8;
}

/* ============================================================
   清华岁月
   ============================================================ */
.tsinghua-intro {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
  margin-bottom: 64px;
}

.tsinghua-text h3 {
  font-size: 24px;
  color: #1b3252;
  margin-bottom: 20px;
  letter-spacing: 0.04em;
}

.tsinghua-text p {
  font-size: 16px;
  color: #444444;
  line-height: 1.9;
}

.photo-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 4px;
}

.photo-item {
  position: relative;
  overflow: hidden;
  cursor: pointer;
  background: #e4ddd4;
  aspect-ratio: 3 / 4;
}

.photo-item--landscape {
  aspect-ratio: 4 / 3;
}

.photo-item--wide {
  grid-column: span 2;
  aspect-ratio: 2 / 1;
}

.photo-item--tall {
  grid-row: span 2;
  aspect-ratio: 3 / 5;
}

.photo-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.photo-item:hover img {
  transform: scale(1.04);
}

.photo-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(27, 50, 82, 0.88);
  color: #ffffff;
  font-size: 12px;
  padding: 10px 14px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
  line-height: 1.4;
  letter-spacing: 0.04em;
}

.photo-item:hover .photo-caption {
  transform: translateY(0);
}

/* 清华岁月大图区 */
.tsinghua-gallery {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  grid-template-rows: auto;
  gap: 6px;
}

.tg-item {
  position: relative;
  overflow: hidden;
  cursor: pointer;
  background: #e4ddd4;
}

.tg-1 { grid-column: 1 / 3; grid-row: 1 / 3; }
.tg-2 { grid-column: 3 / 5; aspect-ratio: 4/3; }
.tg-3 { grid-column: 5 / 7; aspect-ratio: 4/3; }
.tg-4 { grid-column: 3 / 5; aspect-ratio: 4/3; }
.tg-5 { grid-column: 5 / 7; aspect-ratio: 4/3; }
.tg-6 { grid-column: 1 / 4; aspect-ratio: 16/9; }
.tg-7 { grid-column: 4 / 7; aspect-ratio: 16/9; }

.tg-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.tg-item:hover img {
  transform: scale(1.04);
}

.tg-cap {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: rgba(27, 50, 82, 0.85);
  color: #fff;
  font-size: 12px;
  padding: 8px 12px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
  line-height: 1.4;
  letter-spacing: 0.03em;
}

.tg-item:hover .tg-cap {
  transform: translateY(0);
}

/* ============================================================
   文体俱佳
   ============================================================ */
.arts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
}

.art-card {
  background: #ffffff;
  overflow: hidden;
}

.art-photo {
  width: 100%;
  aspect-ratio: 4/3;
  overflow: hidden;
  cursor: pointer;
  background: #e4ddd4;
  position: relative;
}

.art-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.art-photo:hover img {
  transform: scale(1.04);
}

.art-photo .tg-cap {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: rgba(27, 50, 82, 0.85);
  color: #fff;
  font-size: 12px;
  padding: 8px 12px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
}

.art-photo:hover .tg-cap {
  transform: translateY(0);
}

.art-body {
  padding: 32px;
}

.art-icon {
  width: 40px;
  height: 3px;
  background: #b8941a;
  margin-bottom: 20px;
}

.art-title {
  font-size: 22px;
  font-weight: 700;
  color: #1b3252;
  letter-spacing: 0.06em;
  margin-bottom: 16px;
}

.art-body p {
  font-size: 15px;
  color: #555555;
  line-height: 1.85;
}

/* 诗歌展示 */
.poem-card {
  background: #f4f0e8;
  border-left: 4px solid #b8941a;
  padding: 24px 28px;
  margin-top: 20px;
}

.poem-card p {
  font-family: Georgia, "STSong", serif;
  font-size: 15px;
  color: #1b3252;
  line-height: 2;
  margin: 0;
}

.poem-card .poem-source {
  font-size: 12px;
  color: #888888;
  margin-top: 12px;
  letter-spacing: 0.08em;
}

/* ---- 统计带单位文字 ---- */
.stat-num small {
  font-size: 22px;
  font-weight: 700;
  vertical-align: middle;
  margin-left: 2px;
}

/* 文字替代图片的艺术卡片照片区 */
.art-photo--text {
  background: #e8e4dc;
  cursor: default;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 36px 40px;
}

.art-text-bg {
  font-family: Georgia, "STSong", "Source Han Serif SC", serif;
  font-size: 16px;
  color: #1b3252;
  line-height: 2.1;
  font-style: italic;
  text-align: center;
  border-left: 3px solid #b8941a;
  padding-left: 20px;
  text-align: left;
}

.art-text-bg p {
  margin: 0;
}

/* img[data-lb] 鼠标指针 */
img[data-lb] {
  cursor: zoom-in;
}

/* ============================================================
   攻坚铸器 — FAST
   ============================================================ */
.fast-intro {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 72px;
}

.fast-intro p {
  font-size: 18px;
  color: #444444;
  line-height: 1.9;
}

.fast-big-quote {
  font-size: 28px;
  font-family: Georgia, "STSong", serif;
  color: #1b3252;
  font-style: italic;
  margin-bottom: 16px;
  line-height: 1.5;
}

.fast-gallery {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 64px;
}

.fast-photo {
  position: relative;
  overflow: hidden;
  cursor: pointer;
  background: #e4ddd4;
  aspect-ratio: 3/2;
}

.fast-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.fast-photo:hover img {
  transform: scale(1.04);
}

.fast-photo .tg-cap {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: rgba(27, 50, 82, 0.88);
  color: #fff;
  font-size: 12px;
  padding: 10px 14px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
  line-height: 1.4;
}

.fast-photo:hover .tg-cap {
  transform: translateY(0);
}

/* 数字展示块 */
.fast-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
  margin-bottom: 64px;
}

.fast-stat {
  background: #1b3252;
  padding: 48px 32px;
  text-align: center;
}

.fast-stat-num {
  display: block;
  font-size: 64px;
  font-weight: 900;
  color: #c8a83a;
  line-height: 1;
  margin-bottom: 12px;
  font-family: Georgia, serif;
}

.fast-stat-unit {
  font-size: 22px;
}

.fast-stat-desc {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.72);
  letter-spacing: 0.1em;
  line-height: 1.5;
}

/* FAST模型区 */
.fast-model {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.fast-model-text h3 {
  font-size: 24px;
  color: #1b3252;
  margin-bottom: 20px;
  letter-spacing: 0.04em;
}

.fast-model-text p {
  font-size: 16px;
  color: #444444;
  line-height: 1.9;
}

.fast-model-photo {
  position: relative;
  overflow: hidden;
  cursor: pointer;
  background: #e4ddd4;
  aspect-ratio: 4/3;
}

.fast-model-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.fast-model-photo:hover img {
  transform: scale(1.04);
}

.fast-model-photo .tg-cap {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: rgba(27, 50, 82, 0.88);
  color: #fff;
  font-size: 12px;
  padding: 10px 14px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
  line-height: 1.4;
}

.fast-model-photo:hover .tg-cap {
  transform: translateY(0);
}

/* ============================================================
   星耀寰宇
   ============================================================ */
.legacy-section {
  background: #faf7f2;
  padding: 96px 0;
}

.legacy-quote-block {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 72px;
  padding: 56px;
  border: 1px solid #d0c5b5;
  position: relative;
}

.legacy-quote-block::before,
.legacy-quote-block::after {
  content: '';
  position: absolute;
  width: 24px;
  height: 24px;
  border-color: #b8941a;
  border-style: solid;
}

.legacy-quote-block::before {
  top: -2px; left: -2px;
  border-width: 3px 0 0 3px;
}

.legacy-quote-block::after {
  bottom: -2px; right: -2px;
  border-width: 0 3px 3px 0;
}

.legacy-quote {
  font-size: 24px;
  font-family: Georgia, "STSong", serif;
  color: #1b3252;
  line-height: 1.7;
  margin-bottom: 20px;
}

.legacy-quote-attr {
  font-size: 13px;
  color: #888888;
  letter-spacing: 0.12em;
}

/* 荣誉时间线 */
.honors-list {
  max-width: 800px;
  margin: 0 auto;
}

.honor-item {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: 32px;
  padding: 28px 0;
  border-bottom: 1px solid #e8e2d8;
  align-items: start;
}

.honor-item:last-child {
  border-bottom: none;
}

.honor-year {
  font-size: 18px;
  font-weight: 700;
  color: #b8941a;
  font-family: Georgia, serif;
  text-align: right;
  padding-top: 2px;
}

.honor-content h4 {
  font-size: 16px;
  color: #1b3252;
  margin-bottom: 6px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.honor-content p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
}

/* ============================================================
   尾章 — 结语
   ============================================================ */
.epilogue {
  background: #1b3252;
  padding: 96px 0;
  text-align: center;
}

.epilogue-inner {
  max-width: 700px;
  margin: 0 auto;
  padding: 0 48px;
}

.epilogue-date {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.2em;
  margin-bottom: 36px;
  text-transform: uppercase;
  font-family: Georgia, serif;
}

.epilogue-text {
  font-size: 20px;
  color: rgba(255, 255, 255, 0.92);
  line-height: 1.9;
  font-family: Georgia, "STSong", serif;
  margin-bottom: 48px;
}

.epilogue-star {
  font-size: 36px;
  color: #c8a83a;
  margin-bottom: 20px;
  letter-spacing: 0.08em;
  font-family: Georgia, serif;
  font-weight: 700;
}

.epilogue-name {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
  letter-spacing: 0.2em;
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  background: #f4f0e8;
  padding: 28px 0;
  text-align: center;
  border-top: 1px solid #d0c5b5;
}

.site-footer p {
  font-size: 12px;
  color: #aaaaaa;
  letter-spacing: 0.1em;
}

/* ============================================================
   灯箱
   ============================================================ */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.88);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  padding: 40px;
}

.lightbox.open {
  display: flex;
}

.lb-close {
  position: absolute;
  top: 24px;
  right: 32px;
  font-size: 32px;
  color: rgba(255, 255, 255, 0.7);
  transition: color 0.2s;
  line-height: 1;
  padding: 4px 8px;
}

.lb-close:hover {
  color: #ffffff;
}

.lb-img-wrap {
  max-width: 900px;
  max-height: 80vh;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.lb-img-wrap img {
  max-width: 100%;
  max-height: 80vh;
  object-fit: contain;
  box-shadow: 0 8px 48px rgba(0, 0, 0, 0.5);
}

.lb-caption {
  margin-top: 20px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.65);
  text-align: center;
  letter-spacing: 0.08em;
  max-width: 600px;
  line-height: 1.6;
}

.lb-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255, 255, 255, 0.7);
  font-size: 20px;
  transition: border-color 0.2s, color 0.2s;
}

.lb-nav:hover {
  border-color: rgba(255, 255, 255, 0.9);
  color: #ffffff;
}

.lb-prev { left: 24px; }
.lb-next { right: 24px; }

/* ============================================================
   Tooltip for tl items
   ============================================================ */
.tl-item:hover .tl-text {
  color: #1b3252;
}

/* ============================================================
   精简展陨版新增样式
   ============================================================ */

/* 展区头部 */
.exhibit-section {
  background: #faf7f2;
  padding: 64px 0 0;
}

.exhibit-section--plain {
  background: #f4f0e8;
}

.exhibit-head {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 48px 36px;
  text-align: center;
}

.exhibit-tag {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.22em;
  color: #b8941a;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.exhibit-title {
  font-size: 36px;
  font-weight: 700;
  color: #1b3252;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
}

.exhibit-note {
  font-size: 15px;
  color: #666666;
  line-height: 1.7;
  letter-spacing: 0.04em;
  margin: 0;
}

/* 双联图布局 */
.dual-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
}

.dual-item {
  position: relative;
  overflow: hidden;
  background: #e4ddd4;
  aspect-ratio: 3 / 2;
}

.dual-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: zoom-in;
  transition: transform 0.5s ease;
}

.dual-item:hover img {
  transform: scale(1.04);
}

/* 全宽底图 */
.wide-item {
  position: relative;
  overflow: hidden;
  background: #e4ddd4;
  aspect-ratio: 21 / 9;
}

.wide-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: zoom-in;
  transition: transform 0.5s ease;
}

.wide-item:hover img {
  transform: scale(1.04);
}

/* 展区内所有图片悉标提示 */
.dual-item .tg-cap,
.wide-item .tg-cap {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: rgba(27, 50, 82, 0.85);
  color: #fff;
  font-size: 12px;
  padding: 10px 14px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
  line-height: 1.4;
  letter-spacing: 0.04em;
}

.dual-item:hover .tg-cap,
.wide-item:hover .tg-cap {
  transform: translateY(0);
}

/* ============================================================
   移动端适配 (≤ 768px)
   ============================================================ */
@media (max-width: 768px) {

  /* 导航 */
  .site-nav .nav-inner {
    padding: 0 20px;
    position: relative;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: #ffffff;
    border-bottom: 1px solid #e4ddd4;
    flex-direction: column;
    gap: 0;
    padding: 8px 0;
    z-index: 499;
  }

  .nav-links.is-open {
    display: flex;
  }

  .nav-links li a {
    display: block;
    padding: 12px 24px;
    border-bottom: none;
    font-size: 15px;
  }

  .nav-hamburger {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 32px;
    height: 32px;
    cursor: pointer;
    background: transparent;
    border: none;
    padding: 0;
  }

  .nav-hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: #1b3252;
    border-radius: 2px;
    transition: transform 0.25s, opacity 0.25s;
  }

  .nav-hamburger.is-open span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .nav-hamburger.is-open span:nth-child(2) {
    opacity: 0;
  }

  .nav-hamburger.is-open span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  /* Hero */
  .hero-inner {
    padding: 48px 20px;
  }

  .hero-name {
    font-size: 64px;
  }

  .hero-quote {
    font-size: 17px;
    max-width: 100%;
  }

  .hero-subtitle span {
    margin: 0 4px;
  }

  /* 时间轴 */
  .timeline-track {
    justify-content: flex-start;
    padding: 40px 24px 44px;
  }

  .tl-item {
    min-width: 110px;
  }

  /* 展区头部 */
  .exhibit-head {
    padding: 0 20px 28px;
  }

  .exhibit-title {
    font-size: 26px;
  }

  /* 清华岁月图库 → 单列 */
  .tsinghua-gallery {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .tg-1,
  .tg-2,
  .tg-3,
  .tg-4,
  .tg-5,
  .tg-6,
  .tg-7 {
    grid-column: 1;
    grid-row: auto;
    aspect-ratio: 4 / 3;
  }

  /* 移动端图片说明常驻显示 */
  .tg-cap {
    transform: translateY(0) !important;
  }

  /* 双联图 → 单列 */
  .dual-grid {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .dual-item {
    aspect-ratio: 4 / 3;
  }

  /* 全宽图 */
  .wide-item {
    aspect-ratio: 4 / 3;
  }

  /* FAST 数据块 → 单列 */
  .fast-stats {
    grid-template-columns: 1fr;
    gap: 2px;
    margin-bottom: 40px;
  }

  .fast-stat {
    padding: 32px 20px;
  }

  .fast-stat-num {
    font-size: 48px;
  }

  /* 星耀寰宇 */
  .legacy-quote-block {
    padding: 32px 24px;
    margin-bottom: 40px;
  }

  .legacy-quote {
    font-size: 18px;
  }

  .honor-item {
    grid-template-columns: 72px 1fr;
    gap: 16px;
    padding: 20px 0;
  }

  /* 尾章 */
  .epilogue {
    padding: 64px 0;
  }

  .epilogue-inner {
    padding: 0 20px;
  }

  .epilogue-text {
    font-size: 17px;
  }

  .epilogue-star {
    font-size: 28px;
  }

  /* 灯箱 */
  .lightbox {
    padding: 16px;
  }

  .lb-img-wrap {
    max-width: 100%;
  }

  .lb-prev { left: 8px; }
  .lb-next { right: 8px; }

  .lb-nav {
    width: 36px;
    height: 36px;
    font-size: 16px;
  }

  .lb-close {
    top: 12px;
    right: 16px;
    font-size: 24px;
  }
}

/* 超小屏 (≤ 400px) */
@media (max-width: 400px) {
  .hero-name {
    font-size: 52px;
  }

  .nav-logo {
    font-size: 13px;
    letter-spacing: 0.08em;
  }
}