/* ============================================================
   华夏长卷 · 上下五千年 —— 交互式中国通史图文展馆
   全局视觉规范（国风低饱和配色 / 字体 / 圆角阴影 / 动效）
   ============================================================ */

/* ---------- 1. 设计变量（配色 / 字体 / 阴影，可直接照搬修改） ---------- */
:root {
  /* 主色调：朱砂红、青墨蓝、山河绿 */
  --c-cinnabar: #9e2b25;   /* 朱砂红 */
  --c-inkblue:  #2c4a52;   /* 青墨蓝 */
  --c-mtngreen: #4a5d3a;   /* 山河绿 */

  /* 辅助色：米黄古卷、浅灰水墨 */
  --c-scroll:   #f3ead6;   /* 米黄古卷底色 */
  --c-scroll-2: #ece0c4;   /* 古卷深一档 */
  --c-ink-gray: #6b6357;   /* 浅灰水墨（正文） */
  --c-ink-deep: #33302a;   /* 深墨（标题） */
  --c-line:     #cbb98f;   /* 描边/分隔线 */
  --c-gold:     #b5893b;   /* 点缀金 */

  /* 层级字号：大标题 / 小标题 / 正文 / 注释 */
  --fs-hero:   clamp(2.4rem, 6vw, 4.2rem);
  --fs-h2:     clamp(1.6rem, 3.6vw, 2.6rem);
  --fs-h3:     clamp(1.15rem, 2.2vw, 1.5rem);
  --fs-body:   clamp(0.95rem, 1.6vw, 1.05rem);
  --fs-note:   clamp(0.78rem, 1.3vw, 0.85rem);

  /* 字体 */
  --font-title: "Source Han Serif SC", "思源宋体", "STZhongsong", "SimSun", serif;
  --font-body:  "Microsoft YaHei", "PingFang SC", "微软雅黑", -apple-system, sans-serif;

  /* 圆角 / 阴影 / 过渡：统一质感 */
  --radius: 12px;
  --shadow-sm: 0 4px 14px rgba(51, 48, 42, 0.12);
  --shadow-md: 0 10px 30px rgba(51, 48, 42, 0.18);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);

  --nav-h: 78px; /* 顶部时间轴高度 */
}

/* ---------- 2. 基础重置 ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: var(--nav-h); }

body {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.9;
  color: var(--c-ink-gray);
  background-color: var(--c-scroll);
  /* 古卷底纹：细腻纸张肌理（纯 CSS，无需图片，避免版权风险） */
  background-image:
    radial-gradient(circle at 20% 30%, rgba(181,137,59,0.05) 0, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(44,74,82,0.05) 0, transparent 40%),
    repeating-linear-gradient(45deg, rgba(203,185,143,0.03) 0 2px, transparent 2px 6px);
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }

h1, h2, h3, .title-font { font-family: var(--font-title); color: var(--c-ink-deep); font-weight: 700; }

a { color: inherit; text-decoration: none; }

/* 通用容器 */
.container { width: min(1120px, 92vw); margin-inline: auto; }

/* ---------- 3. 分区标题（国风印章式） ---------- */
.section { padding: clamp(3rem, 8vw, 6rem) 0; position: relative; }

.sec-head { text-align: center; margin-bottom: clamp(2rem, 5vw, 3.5rem); }
.sec-head h2 {
  font-size: var(--fs-h2);
  letter-spacing: 0.12em;
  position: relative;
  display: inline-block;
}
.sec-head h2::after {
  content: "";
  display: block;
  width: 64px; height: 4px;
  margin: 0.8rem auto 0;
  background: linear-gradient(90deg, transparent, var(--c-cinnabar), transparent);
}
.sec-head p { color: var(--c-ink-gray); font-size: var(--fs-body); margin-top: 0.6rem; letter-spacing: 0.06em; }

/* ---------- 4. 滚动渐入动画基础类（由 JS 添加 .in） ---------- */
.reveal { opacity: 0; transform: translateY(38px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
.reveal.d1 { transition-delay: 0.12s; }
.reveal.d2 { transition-delay: 0.24s; }
.reveal.d3 { transition-delay: 0.36s; }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ============================================================
   模块一：首页全屏首屏（视觉门面）
   ============================================================ */
.hero {
  height: 100vh;
  min-height: 560px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
  color: var(--c-scroll);
}
/* 水墨山河背景：纯 CSS 渐变模拟远山 + 缓慢平移动画 */
.hero__bg {
  position: absolute;
  inset: -6% -12%;
  z-index: 0;
  background:
    radial-gradient(ellipse 60% 45% at 30% 100%, rgba(74,93,58,0.55), transparent 70%),
    radial-gradient(ellipse 70% 50% at 78% 100%, rgba(44,74,82,0.6), transparent 72%),
    linear-gradient(180deg, #1c2b30 0%, #26343a 40%, #33403d 100%);
  animation: heroPan 26s ease-in-out infinite alternate;
}
/* 叠加远山剪影层 */
.hero__mountains {
  position: absolute;
  inset: 0;
  z-index: 1;
  background:
    radial-gradient(ellipse 40% 22% at 18% 92%, #12181a 0 40%, transparent 41%),
    radial-gradient(ellipse 55% 30% at 55% 96%, #1a2124 0 42%, transparent 43%),
    radial-gradient(ellipse 45% 26% at 88% 94%, #10161800 0 40%, transparent 41%);
  opacity: 0.7;
}
@keyframes heroPan {
  0%   { transform: scale(1.05) translate3d(-1.5%, 0, 0); }
  100% { transform: scale(1.12) translate3d(1.5%, -1.5%, 0); }
}
.hero__inner { position: relative; z-index: 2; padding: 0 1rem; }
.hero__seal {
  display: inline-block;
  border: 2px solid rgba(243,234,214,0.7);
  color: var(--c-scroll);
  font-family: var(--font-title);
  padding: 0.2em 0.7em;
  letter-spacing: 0.35em;
  font-size: var(--fs-note);
  margin-bottom: 1.6rem;
  border-radius: 4px;
}
.hero h1 {
  color: var(--c-scroll);
  font-size: var(--fs-hero);
  letter-spacing: 0.16em;
  text-shadow: 0 4px 24px rgba(0,0,0,0.4);
}
.hero__sub {
  margin-top: 1.1rem;
  font-size: var(--fs-h3);
  letter-spacing: 0.24em;
  color: rgba(243,234,214,0.9);
  font-weight: 300;
}
.hero__btn {
  margin-top: 2.6rem;
  display: inline-block;
  padding: 0.85em 2.4em;
  border: 1.5px solid var(--c-gold);
  border-radius: 50px;
  color: var(--c-scroll);
  letter-spacing: 0.2em;
  font-size: var(--fs-body);
  background: rgba(181,137,59,0.12);
  cursor: pointer;
  transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease), background 0.5s var(--ease);
}
.hero__btn:hover {
  transform: scale(1.06);
  background: rgba(181,137,59,0.28);
  box-shadow: 0 0 26px rgba(181,137,59,0.6);
}
/* 标题渐入 */
.hero__seal, .hero h1, .hero__sub, .hero__btn { animation: heroIn 1.2s var(--ease) both; }
.hero h1     { animation-delay: 0.25s; }
.hero__sub   { animation-delay: 0.5s; }
.hero__btn   { animation-delay: 0.8s; }
@keyframes heroIn { from { opacity: 0; transform: translateY(26px); } to { opacity: 1; transform: none; } }
/* 向下滚动提示 */
.hero__scroll {
  position: absolute; bottom: 2rem; left: 50%; transform: translateX(-50%);
  z-index: 2; color: rgba(243,234,214,0.8); font-size: var(--fs-note); letter-spacing: 0.2em;
  animation: bob 2s ease-in-out infinite;
}
@keyframes bob { 0%,100% { transform: translate(-50%,0);} 50% { transform: translate(-50%,10px);} }

/* ============================================================
   模块二：历史总览时间轴（固定顶部导航）
   ============================================================ */
.timeline-nav {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--nav-h);
  z-index: 100;
  background: rgba(243,234,214,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-line);
  box-shadow: var(--shadow-sm);
  transform: translateY(-100%);
  transition: transform 0.6s var(--ease);
}
.timeline-nav.show { transform: translateY(0); }
.timeline-nav__track {
  height: 100%;
  display: flex;
  align-items: center;
  gap: 0.2rem;
  overflow-x: auto;
  padding: 0 1rem;
  padding-right: 84px;           /* 右侧留白，避开右上角的语言切换按钮 */
  scrollbar-width: thin;
}
.timeline-nav__track::-webkit-scrollbar { height: 5px; }
.timeline-nav__track::-webkit-scrollbar-thumb { background: var(--c-line); border-radius: 3px; }
.tl-logo {
  font-family: var(--font-title); font-weight: 700; color: var(--c-cinnabar);
  letter-spacing: 0.15em; white-space: nowrap; padding-right: 0.8rem;
  border-right: 1px solid var(--c-line); margin-right: 0.6rem; flex: none;
}
.tl-node {
  flex: none;
  position: relative;
  padding: 0.5em 0.9em;
  cursor: pointer;
  white-space: nowrap;
  color: var(--c-ink-gray);
  letter-spacing: 0.08em;
  font-size: var(--fs-note);
  border-radius: 8px;
  transition: color 0.3s, background 0.3s;
}
.tl-node::before {
  content: ""; position: absolute; left: 50%; bottom: 2px; transform: translateX(-50%);
  width: 0; height: 3px; background: var(--c-cinnabar); border-radius: 3px; transition: width 0.3s var(--ease);
}
.tl-node:hover { color: var(--c-cinnabar); background: rgba(158,43,37,0.06); }
.tl-node.active { color: var(--c-cinnabar); font-weight: 700; }
.tl-node.active::before { width: 60%; }
/* 悬浮朝代简介气泡 */
.tl-node__tip {
  position: absolute; top: calc(100% + 8px); left: 50%; transform: translateX(-50%) translateY(6px);
  width: max-content; max-width: 220px;
  background: var(--c-ink-deep); color: var(--c-scroll);
  padding: 0.5em 0.8em; border-radius: 8px; font-size: var(--fs-note);
  line-height: 1.5; opacity: 0; pointer-events: none;
  transition: opacity 0.3s, transform 0.3s; box-shadow: var(--shadow-md); z-index: 5;
}
.tl-node__tip::before {
  content: ""; position: absolute; bottom: 100%; left: 50%; transform: translateX(-50%);
  border: 6px solid transparent; border-bottom-color: var(--c-ink-deep);
}
.tl-node:hover .tl-node__tip { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ============================================================
   模块三：分朝代沉浸式图文详情（标准化模板）
   ============================================================ */
.dynasty { padding: clamp(3rem, 7vw, 5.5rem) 0; border-top: 1px dashed var(--c-line); }
.dynasty:first-of-type { border-top: none; }

/* 朝代铭牌 */
.dyn-plate { text-align: center; margin-bottom: 2.4rem; }
.dyn-plate__name {
  font-size: var(--fs-h2); letter-spacing: 0.18em; color: var(--c-cinnabar);
  position: relative; display: inline-block;
}
.dyn-plate__period { display: block; font-size: var(--fs-note); color: var(--c-ink-gray); letter-spacing: 0.2em; margin-top: 0.5rem; }
.dyn-plate__tag {
  display: inline-block; margin-top: 1rem; padding: 0.35em 1.4em;
  background: var(--c-ink-deep); color: var(--c-scroll); border-radius: 30px;
  font-family: var(--font-title); font-size: var(--fs-h3); letter-spacing: 0.1em;
}

/* 核心图文（图左文右，1:1.2） */
.dyn-hero { display: grid; grid-template-columns: 1fr 1.2fr; gap: clamp(1.5rem, 4vw, 3rem); align-items: center; margin-bottom: 2.6rem; }
.dyn-hero.rev { grid-template-columns: 1.2fr 1fr; }
.dyn-hero.rev .dyn-hero__fig { order: 2; }
.dyn-fig {
  border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-md); border: 6px solid #fff;
  outline: 1px solid var(--c-line); background: var(--c-scroll-2);
}
.dyn-fig img { width: 100%; height: 100%; object-fit: cover; aspect-ratio: 4/3; transition: transform 1.2s var(--ease); }
.dyn-fig:hover img { transform: scale(1.06); }
.dyn-hero__txt h4 { font-family: var(--font-title); color: var(--c-inkblue); font-size: var(--fs-h3); margin-bottom: 0.8rem; letter-spacing: 0.06em; }
.dyn-hero__txt p { margin-bottom: 0.9rem; }

/* 重大事件卡片（悬浮翻转） */
.dyn-block-title { font-family: var(--font-title); color: var(--c-ink-deep); font-size: var(--fs-h3); margin: 2rem 0 1.2rem; letter-spacing: 0.08em; }
.dyn-block-title::before { content: "❖"; color: var(--c-gold); margin-right: 0.5em; }
.event-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 1.2rem; }
.flip-card { perspective: 1200px; height: 180px; cursor: pointer; }
.flip-card__inner {
  position: relative; width: 100%; height: 100%;
  transition: transform 0.7s var(--ease); transform-style: preserve-3d;
}
.flip-card:hover .flip-card__inner, .flip-card.flipped .flip-card__inner { transform: rotateY(180deg); }
.flip-card__face {
  position: absolute; inset: 0; backface-visibility: hidden;
  border-radius: var(--radius); padding: 1.2rem; display: flex; flex-direction: column;
  justify-content: center; box-shadow: var(--shadow-sm); border: 1px solid var(--c-line);
}
.flip-card__front { background: linear-gradient(150deg, var(--c-scroll) 0%, var(--c-scroll-2) 100%); text-align: center; }
.flip-card__front .ev-year { color: var(--c-cinnabar); font-family: var(--font-title); font-size: var(--fs-h3); letter-spacing: 0.05em; }
.flip-card__front .ev-name { font-family: var(--font-title); color: var(--c-ink-deep); font-size: 1.1rem; margin-top: 0.6rem; letter-spacing: 0.06em; }
.flip-card__front .ev-hint { font-size: var(--fs-note); color: var(--c-ink-gray); margin-top: auto; opacity: 0.7; }
.flip-card__back { background: var(--c-inkblue); color: var(--c-scroll); transform: rotateY(180deg); font-size: var(--fs-note); line-height: 1.7; }
.flip-card__back strong { color: var(--c-gold); font-family: var(--font-title); display: block; margin-bottom: 0.4rem; letter-spacing: 0.06em; }

/* 国宝文物展示 */
.relic-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1.4rem; }
.relic-card {
  background: #fff; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-sm); border: 1px solid var(--c-line);
  transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease);
}
.relic-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); }
.relic-card__img { position: relative; overflow: hidden; cursor: zoom-in; aspect-ratio: 4/3; background: var(--c-scroll-2); }
.relic-card__img img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.8s var(--ease); }
.relic-card:hover .relic-card__img img { transform: scale(1.08); }
.relic-card__img::after {
  content: "🔍 点击放大"; position: absolute; inset: auto 0 0 0; padding: 0.4em;
  background: rgba(51,48,42,0.7); color: var(--c-scroll); font-size: var(--fs-note);
  text-align: center; opacity: 0; transition: opacity 0.4s;
}
.relic-card:hover .relic-card__img::after { opacity: 1; }
.relic-card__body { padding: 1rem 1.1rem 1.2rem; }
.relic-card__body h5 { font-family: var(--font-title); color: var(--c-cinnabar); font-size: 1.1rem; margin-bottom: 0.4rem; letter-spacing: 0.05em; }
.relic-card__body p { font-size: var(--fs-note); line-height: 1.7; }

/* 图片降级占位：接口拿不到真图时，用国风底纹 + 印章名牌兜底，避免留白 / 裂图 / 错误默认图 */
.img-fallback {
  position: relative;
  aspect-ratio: 4/3;
  background:
    radial-gradient(circle at 30% 30%, rgba(158,43,37,0.10), transparent 55%),
    radial-gradient(circle at 75% 70%, rgba(44,74,82,0.12), transparent 55%),
    repeating-linear-gradient(45deg, rgba(203,185,143,0.10) 0 6px, transparent 6px 14px),
    var(--c-scroll-2);
}
/* 底层水印大字 */
.img-fallback::before {
  content: "華夏長卷";
  position: absolute; inset: 0; display: grid; place-items: center;
  font-family: var(--font-title); letter-spacing: 0.3em;
  color: rgba(158,43,37,0.14); font-size: clamp(1.6rem, 6vw, 3rem);
  pointer-events: none; z-index: 1;
}
/* 上层印章名牌：显示文物 / 朝代名称（取自 img alt），保证信息不丢失。
   用 !important 覆盖 .relic-card__img::after 的“点击放大”提示（降级后没有真图可放大）。 */
.img-fallback::after {
  content: attr(data-ph-label) !important;
  position: absolute; left: 50%; top: 50%; right: auto; bottom: auto;
  transform: translate(-50%, -50%);
  max-width: 78%; padding: 0.55em 1em !important; text-align: center;
  font-family: var(--font-title); font-size: clamp(0.95rem, 2.4vw, 1.25rem);
  letter-spacing: 0.12em; line-height: 1.4;
  color: var(--c-cinnabar) !important;
  background: rgba(243,234,214,0.86) !important;
  border: 1.5px solid var(--c-cinnabar);
  border-radius: 6px;
  box-shadow: 0 4px 14px rgba(51,48,42,0.14), inset 0 0 0 3px rgba(243,234,214,0.9);
  opacity: 1 !important; z-index: 2;
}
.relic-card__img.img-fallback { cursor: default; }

/* 冷知识彩蛋 */
.fun-fact {
  margin-top: 2rem; padding: 1.2rem 1.4rem; border-left: 4px solid var(--c-gold);
  background: rgba(181,137,59,0.08); border-radius: 0 var(--radius) var(--radius) 0;
  font-size: var(--fs-body);
}
.fun-fact strong { color: var(--c-gold); font-family: var(--font-title); letter-spacing: 0.06em; }

/* 朝代翻页跳转导航 */
.dyn-pager {
  display: flex; align-items: stretch; gap: 0.8rem; margin-top: 2.6rem;
  padding-top: 1.6rem; border-top: 1px dashed var(--c-line);
}
.dyn-pager__btn {
  flex: 1; display: flex; flex-direction: column; gap: 0.2rem;
  padding: 0.7em 1.1em; background: #fff; border: 1px solid var(--c-line);
  border-radius: var(--radius); box-shadow: var(--shadow-sm);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease), border-color 0.4s;
}
.dyn-pager__btn.next { text-align: right; }
.dyn-pager__btn:not(.is-disabled):hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--c-cinnabar); }
.dyn-pager__btn.is-disabled { opacity: 0.5; box-shadow: none; justify-content: center; text-align: center; }
.dyn-pager__dir { font-size: var(--fs-note); color: var(--c-ink-gray); letter-spacing: 0.08em; }
.dyn-pager__name { font-family: var(--font-title); color: var(--c-cinnabar); font-size: 1.05rem; letter-spacing: 0.06em; }
.dyn-pager__top {
  flex: none; align-self: center; padding: 0.7em 1.2em; border-radius: 30px;
  background: var(--c-ink-deep); color: var(--c-scroll); font-size: var(--fs-note);
  letter-spacing: 0.1em; white-space: nowrap; transition: background 0.4s, transform 0.4s var(--ease);
}
.dyn-pager__top:hover { background: var(--c-cinnabar); transform: scale(1.05); }

/* 跳转后目标朝代铭牌高亮动画（明确“跳到哪了”） */
.dyn-plate.jump-hl .dyn-plate__name { animation: jumpHl 1.6s var(--ease); }
@keyframes jumpHl {
  0%   { text-shadow: 0 0 0 rgba(158,43,37,0); }
  25%  { text-shadow: 0 0 22px rgba(158,43,37,0.7); transform: scale(1.06); }
  100% { text-shadow: 0 0 0 rgba(158,43,37,0); transform: scale(1); }
}

/* 顶部阅读进度条 */
.progress-track { position: fixed; top: 0; left: 0; right: 0; height: 3px; z-index: 130; background: transparent; pointer-events: none; }
.progress-bar { height: 100%; width: 0; background: linear-gradient(90deg, var(--c-gold), var(--c-cinnabar)); transition: width 0.15s linear; }

/* ============================================================
   模块四：历史专题合集（横向拖拽滚动）
   ============================================================ */
.topics { background: linear-gradient(180deg, transparent, rgba(44,74,82,0.06), transparent); }
.topic-scroller {
  display: flex; gap: 1.4rem; overflow-x: auto; padding: 0.5rem 0.2rem 1.5rem;
  scroll-snap-type: x mandatory; cursor: grab; scrollbar-width: thin;
}
.topic-scroller.dragging { cursor: grabbing; scroll-behavior: auto; }
.topic-scroller::-webkit-scrollbar { height: 6px; }
.topic-scroller::-webkit-scrollbar-thumb { background: var(--c-line); border-radius: 3px; }
.topic-card {
  flex: 0 0 min(340px, 80vw); scroll-snap-align: center;
  border-radius: var(--radius); overflow: hidden; position: relative;
  min-height: 360px; box-shadow: var(--shadow-md); color: var(--c-scroll);
  display: flex; flex-direction: column; justify-content: flex-end;
  border: 1px solid var(--c-line);
}
.topic-card__img { position: absolute; inset: 0; z-index: 0; }
.topic-card__img img { width: 100%; height: 100%; object-fit: cover; transition: transform 1s var(--ease); }
.topic-card:hover .topic-card__img img { transform: scale(1.08); }
.topic-card__mask { position: absolute; inset: 0; z-index: 1; background: linear-gradient(180deg, rgba(28,43,48,0.1) 0%, rgba(28,43,48,0.85) 100%); }
.topic-card__body { position: relative; z-index: 2; padding: 1.6rem; }
.topic-card__body h4 { color: var(--c-scroll); font-size: var(--fs-h3); letter-spacing: 0.1em; margin-bottom: 0.6rem; }
.topic-card__body p { font-size: var(--fs-note); line-height: 1.7; color: rgba(243,234,214,0.9); }
.topic-card__tag { display: inline-block; margin-bottom: 0.6rem; padding: 0.2em 0.9em; border: 1px solid var(--c-gold); border-radius: 20px; font-size: var(--fs-note); letter-spacing: 0.1em; color: var(--c-gold); }
.topics__hint { text-align: center; font-size: var(--fs-note); color: var(--c-ink-gray); margin-top: 0.5rem; letter-spacing: 0.1em; }

/* ============================================================
   模块五：历史脉络总结
   ============================================================ */
.summary { background: rgba(236,224,196,0.4); }
.flow { display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: 0.4rem; margin-bottom: 2.5rem; }
.flow__item {
  padding: 0.5em 1em; background: #fff; border: 1px solid var(--c-line); border-radius: 30px;
  font-family: var(--font-title); color: var(--c-ink-deep); font-size: var(--fs-note); letter-spacing: 0.06em;
  box-shadow: var(--shadow-sm);
}
.flow__arrow { color: var(--c-cinnabar); font-weight: 700; }
.insight-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.4rem; }
.insight-card { background: #fff; border-radius: var(--radius); padding: 1.6rem; box-shadow: var(--shadow-sm); border-top: 3px solid var(--c-cinnabar); }
.insight-card h4 { font-family: var(--font-title); color: var(--c-cinnabar); font-size: var(--fs-h3); margin-bottom: 0.7rem; letter-spacing: 0.06em; }
.insight-card p { font-size: var(--fs-body); }

/* ============================================================
   模块六：页脚
   ============================================================ */
.footer { background: var(--c-ink-deep); color: rgba(243,234,214,0.85); text-align: center; padding: 3rem 1rem 2.4rem; }
.footer__title { font-family: var(--font-title); font-size: var(--fs-h3); color: var(--c-scroll); letter-spacing: 0.2em; margin-bottom: 1rem; }
.footer__quote { font-style: italic; letter-spacing: 0.1em; margin-bottom: 1.4rem; opacity: 0.9; }
.footer__meta { font-size: var(--fs-note); line-height: 1.9; opacity: 0.65; }
.footer__meta a { color: var(--c-gold); }

/* ============================================================
   悬浮控件：背景音乐 / 回到顶部
   ============================================================ */
.floating { position: fixed; right: 22px; bottom: 26px; z-index: 120; display: flex; flex-direction: column; gap: 12px; }
.fab {
  width: 50px; height: 50px; border-radius: 50%; border: 1px solid var(--c-line);
  background: rgba(243,234,214,0.95); color: var(--c-cinnabar); cursor: pointer;
  box-shadow: var(--shadow-md); font-size: 1.3rem; display: grid; place-items: center;
  transition: transform 0.4s var(--ease), background 0.4s; backdrop-filter: blur(4px);
}
.fab:hover { transform: scale(1.1); background: #fff; }
.fab.playing { background: var(--c-cinnabar); color: var(--c-scroll); animation: spin 4s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
#topBtn { opacity: 0; pointer-events: none; transition: opacity 0.4s; }
#topBtn.show { opacity: 1; pointer-events: auto; }

/* ============================================================
   图片放大弹窗（Lightbox）
   ============================================================ */
.lightbox {
  position: fixed; inset: 0; z-index: 200; background: rgba(20,18,15,0.9);
  display: flex; align-items: center; justify-content: center; flex-direction: column;
  opacity: 0; pointer-events: none; transition: opacity 0.4s; padding: 4vh 4vw;
}
.lightbox.show { opacity: 1; pointer-events: auto; }
.lightbox img { max-width: 90vw; max-height: 78vh; border-radius: 8px; border: 4px solid #fff; box-shadow: var(--shadow-md); }
.lightbox__cap { color: var(--c-scroll); margin-top: 1rem; letter-spacing: 0.1em; text-align: center; max-width: 640px; }
.lightbox__close { position: absolute; top: 20px; right: 28px; font-size: 2rem; color: var(--c-scroll); cursor: pointer; line-height: 1; }

/* ============================================================
   小知识悬浮弹窗（随机冷知识）
   ============================================================ */
.knowledge-pop {
  position: fixed; left: 22px; bottom: 26px; z-index: 115; max-width: 320px;
  background: var(--c-inkblue); color: var(--c-scroll); border-radius: var(--radius);
  padding: 1rem 1.2rem; box-shadow: var(--shadow-md); border: 1px solid var(--c-gold);
  transform: translateX(-120%); transition: transform 0.6s var(--ease);
}
.knowledge-pop.show { transform: translateX(0); }
.knowledge-pop strong { color: var(--c-gold); font-family: var(--font-title); display: block; margin-bottom: 0.4rem; letter-spacing: 0.08em; }
.knowledge-pop p { font-size: var(--fs-note); line-height: 1.7; }
.knowledge-pop__close { position: absolute; top: 6px; right: 12px; cursor: pointer; opacity: 0.7; }

/* ============================================================
   响应式适配（移动端）
   ============================================================ */
@media (max-width: 760px) {
  :root { --nav-h: 62px; }
  .dyn-hero, .dyn-hero.rev { grid-template-columns: 1fr; }
  .dyn-hero.rev .dyn-hero__fig { order: 0; }
  .hero__sub { letter-spacing: 0.14em; }
  .tl-logo { font-size: var(--fs-note); }
  .flow { gap: 0.3rem; }
  .knowledge-pop { left: 12px; right: 12px; max-width: none; }
  .floating { right: 14px; bottom: 16px; }
  .dyn-pager { flex-wrap: wrap; gap: 0.6rem; }
  .dyn-pager__top { order: -1; flex: 1 0 100%; text-align: center; }
  .dyn-pager__name { font-size: 0.95rem; }
}

/* ============================================================
   中英双语切换按钮（右上角固定，国风印章风格）
   ============================================================ */
.lang-toggle {
  position: fixed; top: 18px; right: 18px; z-index: 260;
  min-width: 46px; height: 40px; padding: 0 14px;
  background: var(--c-cinnabar); color: #fff; cursor: pointer;
  border: 1px solid var(--c-gold); border-radius: 22px;
  font-family: var(--font-title); font-size: 0.95rem; font-weight: 700; letter-spacing: 0.08em;
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s var(--ease), background 0.25s, box-shadow 0.25s;
}
.lang-toggle:hover { transform: translateY(-2px); background: #b5342d; box-shadow: var(--shadow-md); }
.lang-toggle:active { transform: translateY(0); }
@media (max-width: 760px) {
  .lang-toggle { top: 12px; right: 12px; height: 36px; min-width: 42px; padding: 0 12px; font-size: 0.9rem; }
}

/* ============================================================
   英文语言下的排版微调（切到 EN 时 <body class="lang-en">）
   英文没有汉字方块感，适当收紧行高、放宽字距，正文改用衬线体更耐读；
   同时避免过长英文单词把卡片撑破（断词换行）。
   ============================================================ */
body.lang-en { line-height: 1.72; }
body.lang-en p,
body.lang-en .dyn-hero__txt p,
body.lang-en .relic-card__body p,
body.lang-en .topic-card__body p,
body.lang-en .insight-card p,
body.lang-en .flip-card__back span,
body.lang-en .footer__meta {
  font-family: Georgia, "Times New Roman", var(--font-body), serif;
  letter-spacing: 0.005em;
  word-break: normal; overflow-wrap: anywhere; hyphens: auto;
}
body.lang-en .dyn-plate__period { letter-spacing: 0.02em; }
body.lang-en .flow__item { font-size: 0.9em; }          /* 英文朝代名较长，略缩小 */
body.lang-en .ev-name { line-height: 1.3; }
body.lang-en .flip-card__back span { font-size: 0.92rem; line-height: 1.55; }