:root{
  --brand:#1f5fc8;
  --brand-dark:#173e85;
  --text:#111827;
  --muted:#66748a;
  --line:#d7e5fb;
  --soft:#f3f7ff;
  --radius:24px;
}
*{box-sizing:border-box}
body{
  margin:0;
  font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  color:var(--text);
  background:#f6f9ff;
  line-height:1.75;
}
a{color:inherit}
.container{width:min(100% - 48px,1180px);margin:0 auto}
.topbar{
  position:sticky;
  top:0;
  z-index:20;
  background:rgba(255,255,255,.92);
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--line);
}
.nav{
  min-height:74px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
}
.brand{
  display:flex;
  flex-direction:column;
  text-decoration:none;
  color:var(--brand-dark);
  font-weight:900;
  line-height:1.15;
}
.brand span{font-size:13px;color:var(--muted);font-weight:700}
.nav-links{display:flex;flex-wrap:wrap;align-items:center;gap:18px}
.nav-links a{
  text-decoration:none;
  color:#52627a;
  font-size:14px;
  font-weight:800;
}
.nav-links a:hover{color:var(--brand)}
.hero{
  padding:72px 0 42px;
  background:linear-gradient(180deg,#fff,#f6f9ff);
}
.eyebrow{
  font-size:13px;
  font-weight:900;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--brand);
  margin-bottom:14px;
}
.hero h1{
  font-size:clamp(36px,5vw,58px);
  line-height:1.12;
  letter-spacing:0;
  margin:0 0 18px;
}
.hero-desc{
  max-width:820px;
  color:#4f5f76;
  font-size:18px;
  margin:0;
}
.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  color:var(--muted);
  font-size:14px;
  margin-bottom:20px;
}
.breadcrumb a{text-decoration:none;color:var(--brand)}
.meta-row{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  margin-top:22px;
}
.pill{
  display:inline-flex;
  align-items:center;
  border:1px solid var(--line);
  background:#fff;
  border-radius:999px;
  padding:8px 13px;
  color:var(--brand-dark);
  font-size:13px;
  font-weight:800;
}
.knowledge-main{padding:38px 0 82px}
.article-list{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:20px;
}
.article-card{
  display:flex;
  flex-direction:column;
  gap:16px;
  min-height:100%;
  background:#fff;
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:24px;
  box-shadow:0 18px 42px rgba(31,79,163,.08);
}
.article-card h2{
  margin:0;
  font-size:24px;
  line-height:1.28;
}
.article-card h2 a{text-decoration:none}
.article-card h2 a:hover{color:var(--brand)}
.article-card p{
  margin:0;
  color:var(--muted);
}
.card-meta{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  color:var(--muted);
  font-size:13px;
}
.tag-row{display:flex;flex-wrap:wrap;gap:8px}
.tag{
  display:inline-flex;
  align-items:center;
  background:#eef5ff;
  color:var(--brand);
  border-radius:999px;
  padding:6px 10px;
  font-size:12px;
  font-weight:800;
}
.read-more{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:max-content;
  margin-top:auto;
  background:var(--brand);
  color:#fff;
  text-decoration:none;
  border-radius:999px;
  padding:10px 18px;
  font-weight:900;
}
.read-more:hover{background:var(--brand-dark)}
.article-layout{
  display:grid;
  grid-template-columns:260px minmax(0,1fr);
  gap:28px;
  align-items:start;
}
.toc{
  position:sticky;
  top:96px;
  background:#fff;
  border:1px solid var(--line);
  border-radius:20px;
  padding:20px;
  box-shadow:0 18px 42px rgba(31,79,163,.08);
}
.toc strong{display:block;margin-bottom:10px}
.toc a{
  display:block;
  text-decoration:none;
  color:var(--muted);
  padding:8px 0;
  border-bottom:1px solid #eef3fb;
  font-size:14px;
}
.toc a:hover{color:var(--brand)}
.toc .toc-h3{padding-left:14px;font-size:13px}
.article-shell{
  background:#fff;
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:34px;
  box-shadow:0 20px 46px rgba(31,79,163,.08);
}
.cover{
  width:100%;
  max-height:420px;
  object-fit:cover;
  border-radius:20px;
  border:1px solid var(--line);
  margin-bottom:28px;
}
.summary-box{
  background:linear-gradient(135deg,#eef5ff,#fff);
  border:1px solid var(--line);
  border-radius:20px;
  padding:22px;
  margin-bottom:28px;
}
.summary-box h2,
.article-content h2,
.faq-section h2,
.related h2{
  font-size:26px;
  line-height:1.3;
  margin:0 0 12px;
}
.summary-box p,
.article-content p,
.faq-section p,
.related p{
  color:#4f5f76;
  margin:0 0 16px;
}
.article-content h2{padding-top:12px}
.article-content h3{
  font-size:21px;
  margin:24px 0 10px;
}
.article-content ul,
.article-content ol{
  color:#4f5f76;
  margin:0 0 22px;
  padding-left:22px;
}
.article-content li{margin:7px 0}
.article-content blockquote{
  margin:22px 0;
  padding:16px 20px;
  border-left:4px solid var(--brand);
  background:#f7faff;
  color:#4f5f76;
}
.faq-section{
  border-top:1px solid var(--line);
  padding-top:28px;
  margin-top:30px;
}
.faq-item{
  padding:16px 0;
  border-bottom:1px solid #eef3fb;
}
.faq-item h3{
  margin:0 0 6px;
  font-size:18px;
}
.related{
  margin-top:30px;
  border-top:1px solid var(--line);
  padding-top:28px;
}
.related-grid{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:14px;
}
.related-card{
  border:1px solid var(--line);
  border-radius:18px;
  padding:16px;
  text-decoration:none;
  background:#fbfdff;
}
.related-card strong{display:block;line-height:1.35}
.related-card span{display:block;color:var(--muted);font-size:13px;margin-top:8px}
.cta{
  margin-top:30px;
  background:linear-gradient(135deg,var(--brand-dark),var(--brand));
  color:#fff;
  border-radius:22px;
  padding:28px;
}
.cta h2{margin:0 0 10px;font-size:24px}
.cta p{color:#e8f0ff;margin:0 0 14px}
.cta a{
  display:inline-flex;
  background:#fff;
  color:var(--brand);
  text-decoration:none;
  font-weight:900;
  border-radius:999px;
  padding:10px 18px;
}
.footer{
  background:#113b82;
  color:#dce8ff;
  padding:34px 0;
}
.footer-grid{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px;
}
.footer a{color:#fff;text-decoration:none;font-weight:800}
.footer-icp{
  margin-top:18px;
  padding-top:16px;
  border-top:1px solid rgba(255,255,255,.16);
  font-size:13px;
  color:#dce8ff;
}
.footer-icp a{
  color:inherit;
  text-decoration:none;
  font-weight:700;
}
@media(max-width:900px){
  .article-list{grid-template-columns:1fr}
  .article-layout{grid-template-columns:1fr}
  .toc{position:relative;top:auto}
  .related-grid{grid-template-columns:1fr}
}
@media(max-width:640px){
  .container{width:min(100% - 28px,1180px)}
  .nav{align-items:flex-start;flex-direction:column;padding:16px 0}
  .nav-links{gap:12px}
  .hero{padding:48px 0 30px}
  .article-shell{padding:24px 18px}
  .footer-grid{align-items:flex-start;flex-direction:column}
}