/* ============================================================
   tang · 唐朝建立与"贞观之治" —— 全局样式
   版本: 1.0.0
   发布规则: 修改本文件后，同步将 index.html 中
   /style.css?v=N 与 /app.js?v=N 的 N 批量 +1，
   并将 sw.js 中 CACHE_NAME 版本号同步 +1。
   ============================================================ */
:root{
  --crimson:#9e2b25;      /* 唐红 */
  --crimson-dark:#7a1f1a;
  --gold:#c9a227;         /* 鎏金 */
  --gold-soft:#f0e2b6;
  --paper:#faf5e9;        /* 米黄纸底 */
  --paper-2:#f4ead3;
  --ink:#3b2f2a;          /* 墨色 */
  --ink-2:#6b5a4e;
  --line:#e0d3b8;
  --jade:#2e6b5e;
  --shadow:0 6px 22px rgba(90,60,20,.12);
}
*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;scroll-padding-top:76px;}
body{
  font-family:"Microsoft YaHei","PingFang SC","Noto Sans SC",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  background:var(--paper);
  color:var(--ink);
  line-height:1.8;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
/* ============ 顶部导航栏 ============ */
header.nav{
  position:fixed;top:0;left:0;right:0;z-index:100;
  background:linear-gradient(90deg,#7a1f1a,#9e2b25 55%,#b03a2e);
  color:#fff;
  box-shadow:0 3px 14px rgba(122,31,26,.35);
  /* iOS 刘海屏安全区 */
  padding-top:env(safe-area-inset-top, 0px);
}
.nav-inner{
  max-width:1180px;margin:0 auto;padding:0 20px;
  display:flex;align-items:center;justify-content:space-between;
  height:calc(64px + env(safe-area-inset-top, 0px));
  min-height:64px;
}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:19px;letter-spacing:1px;}
.brand .seal{
  width:38px;height:38px;flex:none;border-radius:8px;
  background:var(--gold);color:#7a1f1a;
  display:flex;align-items:center;justify-content:center;
  font-family:"KaiTi","STKaiti",serif;font-weight:900;font-size:20px;
  box-shadow:inset 0 0 0 2px rgba(122,31,26,.35);
}
.brand small{display:block;font-size:11px;font-weight:400;opacity:.85;letter-spacing:2px;line-height:1.2;}
nav.menu ul{list-style:none;display:flex;gap:4px;}
nav.menu a{
  display:block;padding:8px 13px;color:#ffe9d8;text-decoration:none;
  font-size:15px;border-radius:6px;transition:.2s;
}
nav.menu a:hover{background:rgba(255,255,255,.16);color:#fff;}
nav.menu a.active{background:#fff;color:var(--crimson);font-weight:700;}
.nav-toggle{display:none;background:none;border:none;color:#fff;font-size:26px;cursor:pointer;}

/* ============ 主容器 ============ */
main{
  max-width:1180px;margin:0 auto;padding:20px 20px 60px;
  /* iOS 横屏安全区 */
  padding-left:max(20px, env(safe-area-inset-left));
  padding-right:max(20px, env(safe-area-inset-right));
}

/* ============ Hero ============ */
.hero{
  margin-top:84px;position:relative;overflow:hidden;border-radius:16px;
  background:
    radial-gradient(1200px 400px at 85% -20%,rgba(201,162,39,.28),transparent 60%),
    linear-gradient(135deg,#7a1f1a,#a03026 45%,#c2563a);
  color:#fff;padding:52px 44px;text-align:center;
  box-shadow:var(--shadow);
}
.hero::before{
  content:"";position:absolute;inset:12px;border:1px solid rgba(255,255,255,.25);border-radius:10px;pointer-events:none;
}
.hero .tagline{
  display:inline-block;background:var(--gold);color:#7a1f1a;font-weight:700;
  padding:3px 16px;border-radius:999px;font-size:14px;letter-spacing:3px;margin-bottom:14px;
}
.hero h1{font-family:"KaiTi","STKaiti",serif;font-size:46px;letter-spacing:6px;text-shadow:0 2px 8px rgba(0,0,0,.25);}
.hero .sub{margin-top:10px;font-size:17px;letter-spacing:2px;opacity:.92;}
.hero .meta{margin-top:18px;display:flex;justify-content:center;gap:26px;font-size:14px;opacity:.85;flex-wrap:wrap;}
.hero .meta span{border:1px solid rgba(255,255,255,.4);border-radius:999px;padding:3px 14px;}

/* ============ 章节通用 ============ */
section{
  margin-top:46px;background:#fffdf7;border:1px solid var(--line);border-radius:14px;
  padding:34px 38px;box-shadow:var(--shadow);
}
.sec-head{display:flex;align-items:center;gap:14px;margin-bottom:22px;border-bottom:2px dashed var(--line);padding-bottom:14px;}
.sec-no{
  flex:none;width:44px;height:44px;border-radius:10px;
  background:linear-gradient(135deg,var(--crimson),#c2563a);color:#fff;
  display:flex;align-items:center;justify-content:center;font-size:20px;font-weight:800;
  box-shadow:0 3px 8px rgba(158,43,37,.35);
}
.sec-head h2{font-family:"KaiTi","STKaiti",serif;font-size:27px;color:var(--crimson);letter-spacing:2px;}
.sec-head .en{margin-left:auto;font-size:12px;color:var(--ink-2);letter-spacing:2px;}

/* 引言框 */
.quote{
  background:var(--gold-soft);border-left:5px solid var(--gold);border-radius:8px;
  padding:16px 20px;margin:16px 0;font-family:"KaiTi","STKaiti",serif;font-size:17px;color:#5c4a10;
}
.quote .src{display:block;text-align:right;font-size:13px;margin-top:6px;color:#8a7420;font-family:inherit;}

/* 文本与列表 */
p.lead{font-size:16px;margin-bottom:14px;}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:6px;}
.card{
  background:var(--paper-2);border:1px solid var(--line);border-left:5px solid var(--crimson);
  border-radius:10px;padding:18px 20px;
}
.card h3{font-size:17px;color:var(--crimson);margin-bottom:8px;letter-spacing:1px;}
.card p,.card li{font-size:15px;color:var(--ink-2);}
.card ul{padding-left:20px;}
.card ul li{margin:5px 0;}
.card .key{color:var(--crimson);font-weight:700;}

/* 时间轴 */
.timeline{display:flex;gap:0;margin:22px 0 8px;flex-wrap:wrap;}
.tl-item{flex:1;min-width:150px;position:relative;text-align:center;padding:14px 8px 6px;}
.tl-item::before{
  content:"";position:absolute;top:0;left:0;right:0;height:4px;border-radius:4px;
  background:linear-gradient(90deg,var(--gold),var(--crimson));
}
.tl-item .year{font-size:26px;font-weight:800;color:var(--crimson);font-family:"Georgia",serif;}
.tl-item .evt{font-size:14px;color:var(--ink-2);margin-top:2px;}

/* 表格 */
table.cmp{width:100%;border-collapse:collapse;margin-top:14px;font-size:15px;background:#fff;}
table.cmp th{background:var(--crimson);color:#fff;padding:10px 12px;font-weight:600;}
table.cmp td{border:1px solid var(--line);padding:10px 12px;color:var(--ink-2);}
table.cmp tr:nth-child(even) td{background:var(--paper);}

/* 徽章标签 */
.tag{display:inline-block;background:var(--crimson);color:#fff;font-size:12px;padding:1px 10px;border-radius:999px;margin-right:6px;vertical-align:2px;}

/* ============ 媒体区 ============ */
.media-block{margin-top:20px;}
.media-block .media-title{
  display:flex;align-items:center;gap:8px;font-size:16px;font-weight:700;color:var(--ink);margin-bottom:10px;
}
.media-block .media-title .ico{color:var(--gold);font-size:20px;}
.media-block .media-fill{
  width:100%;aspect-ratio:16/9;border-radius:12px;object-fit:cover;display:block;
  background:#1a1410;border:1px solid var(--line);box-shadow:var(--shadow);
}
.media-block video.media-fill{object-fit:contain;cursor:pointer;}
.media-caption{margin-top:8px;font-size:13px;color:var(--ink-2);text-align:center;letter-spacing:1px;}

/* 占位样式（未填充素材时备用） */
.media-placeholder{
  position:relative;width:100%;aspect-ratio:16/9;border-radius:12px;overflow:hidden;
  background:
    repeating-linear-gradient(45deg,var(--paper-2),var(--paper-2) 14px,#efe3c8 14px,#efe3c8 28px);
  border:2px dashed var(--gold);
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;
  color:var(--ink-2);
}
.media-placeholder .big-ico{font-size:52px;line-height:1;filter:drop-shadow(0 3px 6px rgba(0,0,0,.15));}
.media-placeholder .ph-tip{font-size:16px;font-weight:700;color:var(--crimson);}
.media-placeholder .ph-sub{font-size:13px;color:var(--ink-2);}
.media-placeholder .ph-size{
  position:absolute;bottom:8px;right:12px;font-size:11px;background:rgba(255,255,255,.75);
  border:1px solid var(--line);border-radius:4px;padding:0 8px;
}
.ph-badge{
  position:absolute;top:10px;left:10px;background:var(--crimson);color:#fff;
  font-size:12px;padding:2px 12px;border-radius:999px;letter-spacing:2px;
}
.ph-badge.video{background:var(--jade);}

/* ============ 互动检测 ============ */
.quiz{background:var(--paper-2);border:1px solid var(--line);border-radius:12px;padding:20px 24px;margin-top:8px;}
.quiz h3{color:var(--crimson);margin-bottom:10px;font-size:18px;}
.quiz .q{margin:12px 0;font-size:15px;}
.quiz .q .num{font-weight:800;color:var(--crimson);margin-right:4px;}
.quiz .opts{display:flex;gap:10px;flex-wrap:wrap;margin-top:6px;}
.quiz .opt{
  border:1px solid var(--line);background:#fff;border-radius:8px;padding:6px 18px;cursor:pointer;
  transition:.15s;font-size:14px;
}
.quiz .opt:hover{border-color:var(--gold);background:var(--gold-soft);}
.quiz .opt.correct{background:#d9f2e0;border-color:#2e8b57;color:#1d5c38;font-weight:700;}
.quiz .opt.wrong{background:#f8dcd9;border-color:var(--crimson);color:var(--crimson);text-decoration:line-through;}
.quiz .answer-hint{display:none;margin-top:6px;font-size:13px;color:var(--jade);}

/* ============ 页脚 ============ */
footer{
  background:#4a352c;color:#e8d9c8;text-align:center;padding:22px 20px;
  padding-bottom:calc(22px + env(safe-area-inset-bottom));
  font-size:13px;letter-spacing:1px;line-height:2;
}
footer .seal-inline{
  display:inline-block;background:var(--gold);color:#7a1f1a;font-weight:900;
  padding:0 10px;border-radius:6px;font-family:"KaiTi",serif;margin:0 6px;
}

/* ============ standalone 独立模式 ============ */
@media (display-mode: standalone){
  body{ user-select:none; -webkit-user-select:none; }
  .quiz .opt{ user-select:text; -webkit-user-select:text; }
  .media-block video{ user-select:none; }
}

/* ============ 响应式 ============ */
@media (max-width:860px){
  .nav-toggle{display:block;}
  nav.menu{
    position:absolute;top:100%;left:0;right:0;background:#7a1f1a;
    display:none;flex-direction:column;padding:8px 16px 14px;
    box-shadow:0 8px 16px rgba(0,0,0,.2);
  }
  nav.menu.open{display:flex;}
  nav.menu a{padding:12px 8px;border-bottom:1px solid rgba(255,255,255,.1);}
  .grid2{grid-template-columns:1fr;}
  .hero h1{font-size:32px;letter-spacing:3px;}
  section{padding:24px 20px;}
  .hero{padding:38px 20px;}
}
@media (max-width:480px){
  .hero h1{font-size:26px;}
  .hero .sub{font-size:15px;}
  .sec-head h2{font-size:22px;}
  .tl-item{min-width:110px;}
}