:root{
  --bg:#f5f7fb;
  --surface:#ffffff;
  --text:#172033;
  --muted:#64748b;
  --line:#e5e7eb;
  --accent:#2856d6;
  --accent-soft:#eaf0ff;
  --shadow:0 14px 40px rgba(15,23,42,.08);
  --radius:18px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color:var(--text);
  background:var(--bg);
  line-height:1.75;
}
img{max-width:100%;height:auto;border-radius:14px;display:block;margin:1rem auto}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.site-header{
  position:sticky;top:0;z-index:100;
  display:flex;align-items:center;gap:18px;
  padding:12px clamp(16px,4vw,48px);
  background:rgba(255,255,255,.9);
  backdrop-filter:blur(14px);
  border-bottom:1px solid rgba(226,232,240,.9);
}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);min-width:max-content}
.brand:hover{text-decoration:none}
.brand-mark{
  width:38px;height:38px;border-radius:12px;
  display:grid;place-items:center;
  color:white;background:linear-gradient(145deg,#2856d6,#1d4ed8);
  font-weight:800;
}
.brand span:last-child{display:flex;flex-direction:column;line-height:1.15}
.brand small{font-weight:500;color:var(--muted);font-size:.72rem;margin-top:4px}
.site-nav{display:flex;gap:4px;overflow:auto;margin-left:auto;white-space:nowrap}
.site-nav a{padding:8px 10px;border-radius:10px;color:#334155;font-size:.9rem}
.site-nav a:hover{background:var(--accent-soft);text-decoration:none}
.menu-btn{display:none;margin-left:auto;border:1px solid var(--line);background:white;border-radius:10px;padding:8px 12px}
.hero{
  background:
    radial-gradient(circle at 84% 20%,rgba(255,255,255,.22),transparent 28%),
    linear-gradient(135deg,#173a9c,#2856d6 55%,#4b6ee7);
  color:white;
  padding:clamp(56px,9vw,110px) 20px;
}
.hero-inner{max-width:1100px;margin:auto}
.eyebrow{text-transform:uppercase;letter-spacing:.08em;font-weight:700;opacity:.82;font-size:.82rem}
.hero h1{font-size:clamp(2.4rem,7vw,5.4rem);line-height:1.02;margin:.25rem 0 .5rem}
.hero-cn{font-size:clamp(1.25rem,3vw,2rem);margin:0 0 1rem;font-weight:650}
.hero-copy{max-width:740px;font-size:clamp(1rem,2.1vw,1.18rem);opacity:.92}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}
.button{display:inline-flex;padding:11px 16px;border-radius:12px;font-weight:700}
.button:hover{text-decoration:none}
.button.primary{background:white;color:#173a9c}
.button.ghost{border:1px solid rgba(255,255,255,.45);color:white}
.layout{
  max-width:1240px;margin:0 auto;
  display:grid;grid-template-columns:240px minmax(0,1fr);
  gap:32px;padding:34px 20px 70px;
}
.toc{
  position:sticky;top:84px;align-self:start;
  background:var(--surface);border:1px solid var(--line);
  border-radius:var(--radius);padding:16px;box-shadow:var(--shadow);
}
.toc-title{font-weight:800;margin-bottom:9px}
.toc a{display:block;padding:8px 9px;border-radius:9px;color:#475569;font-size:.91rem}
.toc a:hover,.toc a.active{background:var(--accent-soft);color:var(--accent);text-decoration:none}
.content{
  min-width:0;background:var(--surface);border:1px solid var(--line);
  border-radius:var(--radius);padding:clamp(20px,4vw,46px);
  box-shadow:var(--shadow);
}
.notice{
  padding:16px 18px;border:1px solid #bfdbfe;background:#eff6ff;
  border-radius:14px;margin-bottom:30px;color:#1e3a8a;
}
.content h1,.content h2,.content h3{scroll-margin-top:96px;line-height:1.3}
.content h1{font-size:2rem;margin:2rem 0 1rem}
.content h2{
  margin:2.8rem 0 1rem;padding-top:1rem;border-top:1px solid var(--line);
  font-size:1.55rem;
}
.content h3{font-size:1.16rem;margin:2rem 0 .75rem}
.content p{margin:.75rem 0}
.content ul,.content ol{padding-left:1.35rem}
.content table{
  width:100%;border-collapse:collapse;display:block;overflow-x:auto;
  border:1px solid var(--line);border-radius:12px;margin:1rem 0 1.5rem;
}
.content th,.content td{border-bottom:1px solid var(--line);padding:10px 12px;text-align:left;vertical-align:top}
.content th{background:#f8fafc}
.content blockquote{margin:1rem 0;padding:12px 16px;border-left:4px solid var(--accent);background:#f8fafc}
.content figure{margin:1.5rem 0}
.content figcaption{text-align:center;color:var(--muted);font-size:.9rem;margin-top:.5rem}
footer{max-width:1240px;margin:auto;padding:0 20px 46px;color:#475569}
footer p{margin:.25rem 0}
.muted{color:var(--muted);font-size:.9rem}
.to-top{
  position:fixed;right:18px;bottom:18px;width:44px;height:44px;border:0;border-radius:50%;
  background:#172033;color:white;box-shadow:var(--shadow);font-size:1.1rem;
  opacity:0;pointer-events:none;transition:.2s;
}
.to-top.show{opacity:1;pointer-events:auto}
@media (max-width:900px){
  .site-nav{display:none;position:absolute;left:12px;right:12px;top:68px;flex-direction:column;background:white;border:1px solid var(--line);padding:10px;border-radius:14px;box-shadow:var(--shadow)}
  .site-nav.open{display:flex}
  .menu-btn{display:block}
  .layout{grid-template-columns:1fr;padding:20px 12px 50px}
  .toc{display:none}
  .content{padding:20px 17px}
  .hero{padding:52px 18px}
}
@media (max-width:520px){
  body{font-size:15px}
  .brand small{display:none}
  .brand b{font-size:.96rem}
  .hero h1{font-size:2.55rem}
  .content table{font-size:.9rem}
}
@media print{
  .site-header,.toc,.to-top,.hero-actions{display:none!important}
  body{background:white}
  .hero{color:black;background:white;padding:20px 0}
  .layout{display:block;padding:0}
  .content{border:0;box-shadow:none;padding:0}
}