@charset "gb2312";
:root{
  --ink:#1B2733; --muted:#657686; --line:#DCE4EC; --line2:#EDF2F7;
  --blue:#1F4E79; --blue2:#2E75B6; --teal:#128F8F; --red:#C0392B;
  --orange:#D98B2B; --green:#2E7D32; --bg:#F4F7FA; --card:#FFFFFF;
  --shadow:0 1px 2px rgba(16,42,67,.06),0 8px 24px rgba(16,42,67,.06);
  --mono:"Cascadia Mono","Consolas","SFMono-Regular",ui-monospace,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);
  font:15.5px/1.78 -apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei","PingFang SC",sans-serif;
  -webkit-font-smoothing:antialiased}
a{color:var(--blue2);text-decoration:none}
a:hover{text-decoration:underline}

/* 头部 */
.site-head{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);
  backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.head-inner{max-width:1280px;margin:0 auto;padding:0 22px;height:60px;
  display:flex;align-items:center;gap:20px}
.brand{display:flex;align-items:center;gap:10px;color:var(--ink);flex:0 0 auto}
.brand:hover{text-decoration:none}
.brand-mark{width:34px;height:34px;border-radius:9px;display:grid;place-items:center;
  background:linear-gradient(135deg,var(--blue),var(--teal));color:#fff;font-weight:800;font-size:14px;
  letter-spacing:.5px}
.brand-txt{display:flex;flex-direction:column;line-height:1.15}
.brand-txt b{font-size:15px;letter-spacing:.2px}
.brand-txt i{font-style:normal;font-size:11px;color:var(--muted);letter-spacing:.6px}
.top-nav{display:flex;gap:4px;margin-left:auto;flex-wrap:wrap}
.top-nav a{padding:9px 13px;border-radius:8px;font-size:13.5px;color:var(--muted);white-space:nowrap}
.top-nav a:hover{background:var(--line2);color:var(--blue);text-decoration:none}
.top-nav a.active{background:var(--blue);color:#fff}
.nav-toggle{display:none;margin-left:auto;border:1px solid var(--line);background:#fff;
  border-radius:8px;width:38px;height:34px;cursor:pointer;padding:0}
/* 汉堡图标用纯 CSS 绘制，不依赖任何 GB2312 之外的字符 */
.nav-toggle span{display:block;width:18px;height:2px;margin:3px auto;border-radius:1px;
  background:var(--blue)}

/* Hero */
.hero{background:
  radial-gradient(1100px 400px at 88% -20%,rgba(18,143,143,.35),transparent 60%),
  radial-gradient(900px 380px at 6% -30%,rgba(46,117,182,.5),transparent 60%),
  linear-gradient(135deg,#153552 0%,#1F4E79 55%,#166a6a 100%);
  color:#fff;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;inset:0;opacity:.16;
  background-image:linear-gradient(rgba(255,255,255,.6) 1px,transparent 1px),
                   linear-gradient(90deg,rgba(255,255,255,.6) 1px,transparent 1px);
  background-size:34px 34px;mask-image:linear-gradient(180deg,#000,transparent 92%)}
.hero-inner{max-width:1280px;margin:0 auto;padding:52px 22px 40px;position:relative;z-index:1}
.badge{display:inline-block;font-size:11.5px;letter-spacing:2.5px;font-weight:700;
  padding:5px 12px;border:1px solid rgba(255,255,255,.45);border-radius:999px;
  color:#EAF3FB;margin-bottom:16px}
.hero h1{margin:0 0 12px;font-size:34px;line-height:1.25;letter-spacing:.3px}
.hero-sub{margin:0;max-width:900px;color:#D8E7F4;font-size:16px}
.facts{display:grid;grid-template-columns:repeat(6,1fr);gap:12px;margin-top:28px}
.fact{background:rgba(255,255,255,.10);border:1px solid rgba(255,255,255,.22);
  border-radius:12px;padding:14px 14px 12px;backdrop-filter:blur(4px)}
.fact-num{font-size:21px;font-weight:800;letter-spacing:.3px}
.fact-lab{font-size:12px;color:#CDE0EF;margin-top:3px;line-height:1.4}

/* 布局 */
.layout{max-width:1280px;margin:0 auto;padding:28px 22px 60px;
  display:grid;grid-template-columns:262px minmax(0,1fr);gap:26px;align-items:start}
.side{position:sticky;top:78px;display:flex;flex-direction:column;gap:14px}
.side-card{background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:16px 16px 12px;box-shadow:var(--shadow)}
.side-title{font-size:12.5px;font-weight:800;letter-spacing:1.4px;color:var(--blue);
  text-transform:uppercase;margin-bottom:10px}
.toc-list{list-style:none;margin:0;padding:0;max-height:52vh;overflow:auto}
.toc-list li{margin:1px 0}
.toc-list a{display:block;padding:5px 8px;border-radius:7px;color:#516474;font-size:13.2px;
  border-left:2px solid transparent}
.toc-list a:hover{background:var(--line2);color:var(--blue);text-decoration:none}
.toc-h3 a{padding-left:20px;font-size:12.6px;color:#7a8b9a}
.toc-empty{color:var(--muted);font-size:13px;margin:0}
.side-note p{font-size:12.4px;color:var(--muted);margin:0;line-height:1.65}

.main{min-width:0}
.content{background:var(--card);border:1px solid var(--line);border-radius:16px;
  padding:14px 38px 40px;box-shadow:var(--shadow)}

/* 标题 */
.content h1.chapter{margin:34px 0 14px;font-size:25px;line-height:1.35;color:var(--blue);
  display:flex;align-items:center;gap:12px;padding-bottom:12px;border-bottom:2px solid var(--line)}
.content h1.chapter:first-child{margin-top:16px}
.ch-mark{width:6px;height:26px;border-radius:3px;flex:0 0 auto;
  background:linear-gradient(180deg,var(--red),var(--orange))}
.content h2{margin:34px 0 10px;font-size:20px;color:var(--blue);line-height:1.4;
  scroll-margin-top:80px}
.content h3{margin:24px 0 8px;font-size:16.5px;color:#2C4A66;line-height:1.45;
  scroll-margin-top:80px}
.content h3::before{content:"";display:inline-block;width:8px;height:8px;border-radius:2px;
  background:var(--teal);margin-right:9px;vertical-align:2px}
.content h4{margin:18px 0 6px;font-size:15px;color:#3B5A78}
.content p{margin:11px 0;text-align:justify}
.content strong{color:#12314C}
.content code{font-family:var(--mono);font-size:.9em;background:#EEF4FA;color:#1F4E79;
  padding:1.5px 5px;border-radius:5px;word-break:break-word}

/* 导语 / 提示 */
.lead{margin:16px 0 20px;padding:14px 18px;border-left:4px solid var(--blue2);
  background:#EEF4FB;border-radius:0 10px 10px 0;font-weight:600;color:#173a59;text-align:justify}
.note{margin:16px 0;padding:13px 16px;border-left:4px solid var(--orange);
  background:#FFF8E6;border-radius:0 10px 10px 0;display:flex;gap:11px;align-items:flex-start}
.note-ico{flex:0 0 auto;width:24px;height:24px;border-radius:6px;background:var(--orange);
  color:#fff;font-size:12px;font-weight:800;display:grid;place-items:center;margin-top:1px}
.note-body{color:#6b4a10;font-size:14.6px;text-align:justify}
.note-body strong{color:#5a3d0c}

/* 列表 */
.content ul,.content ol{margin:10px 0;padding-left:24px}
.content li{margin:5px 0;text-align:justify}
.content li::marker{color:var(--teal)}

/* 表格 */
.table-wrap{overflow-x:auto;margin:16px 0;border:1px solid var(--line);border-radius:11px}
table{border-collapse:collapse;width:100%;font-size:13.6px;background:#fff}
thead th{background:linear-gradient(180deg,#2E5C8A,#274F78);color:#fff;font-weight:700;
  text-align:left;padding:10px 12px;white-space:nowrap;border-right:1px solid rgba(255,255,255,.12)}
tbody td{padding:9px 12px;border-top:1px solid var(--line2);vertical-align:top;line-height:1.6}
tbody tr:nth-child(even){background:#F7FAFD}
tbody tr:hover{background:#EEF5FC}
tbody td:first-child{color:#24435F;font-weight:600}
td code,thead code{white-space:nowrap}

/* 代码 */
pre.code{margin:14px 0;background:#F5F8FB;border:1px solid var(--line);border-left:3px solid var(--teal);
  border-radius:9px;padding:13px 15px;overflow-x:auto}
pre.code code{background:none;color:#24435F;font-size:12.8px;line-height:1.65;padding:0}

/* 图片 */
figure.fig{margin:20px 0;padding:0}
figure.fig img{width:100%;height:auto;display:block;border:1px solid var(--line);
  border-radius:12px;background:#fff;box-shadow:var(--shadow)}
figure.fig figcaption{margin-top:9px;text-align:center;font-size:12.8px;color:var(--muted)}
.img-missing{padding:30px;text-align:center;color:var(--red);border:1px dashed var(--red);
  border-radius:12px;background:#FDECEC}
.caption{margin:18px 0 6px;font-weight:700;color:#2C4A66;font-size:14.5px}

/* 分页器 / 页脚 */
.pager{display:flex;justify-content:space-between;gap:12px;margin:22px 0 0}
.pager a{background:#fff;border:1px solid var(--line);border-radius:11px;padding:12px 18px;
  font-size:13.8px;color:var(--blue);box-shadow:var(--shadow);font-weight:600}
.pager a:hover{text-decoration:none;border-color:var(--blue2);color:var(--blue2)}
.pager-next{margin-left:auto}
.foot{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;
  margin-top:26px;padding-top:18px;border-top:1px solid var(--line);color:var(--muted);font-size:12.6px}

/* 回到顶部 */
.to-top{position:fixed;right:22px;bottom:22px;width:42px;height:42px;border-radius:50%;
  border:1px solid var(--line);background:#fff;color:var(--blue);font-size:18px;cursor:pointer;
  box-shadow:var(--shadow);opacity:0;pointer-events:none;transition:.2s}
.to-top.show{opacity:1;pointer-events:auto}
.pagebreak{height:1px;background:var(--line);margin:26px 0}

/* 响应式 */
@media(max-width:1080px){
  .facts{grid-template-columns:repeat(3,1fr)}
  .layout{grid-template-columns:1fr}
  .side{position:static;order:2}
  .toc-list{max-height:none}
}
@media(max-width:720px){
  .top-nav{display:none;order:3;width:100%;flex-direction:column;margin:0;padding-bottom:10px}
  body.nav-open .top-nav{display:flex}
  .head-inner{flex-wrap:wrap;height:auto;padding:10px 16px}
  .nav-toggle{display:block}
  .hero h1{font-size:25px}
  .hero-inner{padding:34px 16px 28px}
  .facts{grid-template-columns:repeat(2,1fr)}
  .layout{padding:18px 12px 44px}
  .content{padding:10px 18px 30px}
  .content h2{font-size:18px}
}

/* 打印 */
@media print{
  .site-head,.side,.to-top,.pager,.hero::after{display:none!important}
  body{background:#fff}
  .layout{display:block;max-width:none;padding:0}
  .content{border:0;box-shadow:none;padding:0}
  .hero{background:#fff;color:#000;padding:0}
  .hero h1{color:#000}.hero-sub{color:#333}.fact{border-color:#ccc}.fact-num{color:#000}
  .fact-lab{color:#333}
  figure.fig img{box-shadow:none}
  a{color:#000}
}