:root{
  --bg:#ffffff;
  --text:#111827;
  --muted:#6b7280;
  --border:#e5e7eb;
  --soft:#f9fafb;
  --card:#ffffff;
  --brand:#111827;

  --radius:16px;
  --shadow:0 8px 22px rgba(0,0,0,.06);
  --container:1100px;
}

*{box-sizing:border-box;}
html,body{height:100%;}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font:16px/1.7 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;
}

a{color:inherit;text-decoration:none;}
a:hover{text-decoration:underline;}
img{max-width:100%;height:auto;display:block;}

.container{
  width:100%;
  max-width:var(--container);
  padding:0 18px;
  margin:0 auto;
}

.skip-link{
  position:absolute;
  left:-999px;
  top:10px;
  background:#000;
  color:#fff;
  padding:10px 12px;
  border-radius:10px;
  z-index:999;
}
.skip-link:focus{left:12px;}

.site-header{
  position:sticky;
  top:0;
  background:rgba(255,255,255,.92);
  border-bottom:1px solid var(--border);
  backdrop-filter:saturate(180%) blur(10px);
  z-index:50;
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  padding:12px 0;
}

.brand{
  display:flex;
  align-items:center;
  gap:10px;
  font-weight:700;
}
.brand-mark{
  width:34px;height:34px;
  border-radius:10px;
  background:var(--brand);
  color:#fff;
  display:grid;
  place-items:center;
  font-weight:800;
}
.brand-text{letter-spacing:.2px;}

.nav{display:flex; gap:10px; align-items:center;}
.nav-link{
  padding:8px 10px;
  border-radius:12px;
  color:var(--muted);
}
.nav-link.is-active{
  background:var(--soft);
  color:var(--text);
  border:1px solid var(--border);
}

.section{padding:42px 0;}
.section-alt{background:var(--soft); border-top:1px solid var(--border); border-bottom:1px solid var(--border);}
.section-mini{padding:26px 0;}

.hero{
  padding:44px 0 32px;
  background:linear-gradient(180deg, #ffffff 0%, #f9fafb 100%);
  border-bottom:1px solid var(--border);
}
.hero-inner{
  display:grid;
  grid-template-columns: 1.5fr .9fr;
  gap:22px;
  align-items:start;
}
.hero h1{font-size:34px; line-height:1.2; margin:0 0 14px;}
.lead{font-size:18px; color:#1f2937; margin:0 0 18px;}
.meta-list{margin:16px 0 0; padding:0 0 0 18px; color:var(--muted);}
.hero-card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px;
  box-shadow:var(--shadow);
}

.section-head{margin:0 0 18px;}
.section-head h2{margin:0 0 6px; font-size:22px;}
.muted{color:var(--muted);}
.small{font-size:13px;}

.grid{display:grid; gap:14px;}
.grid-2{grid-template-columns:repeat(2, minmax(0,1fr));}
.grid-3{grid-template-columns:repeat(3, minmax(0,1fr));}

.card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px;
  box-shadow:var(--shadow);
}
.card-dashed{
  background:transparent;
  box-shadow:none;
  border:1px dashed var(--border);
}
.h3{font-size:18px; margin:0 0 10px;}
.h4{font-size:16px; margin:0 0 8px;}
.card-link{display:inline-block; margin-top:10px; color:#111827; font-weight:600;}

.btn{
  display:inline-block;
  padding:10px 14px;
  border-radius:14px;
  background:#111827;
  color:#fff;
  border:1px solid #111827;
  font-weight:700;
}
.btn:hover{text-decoration:none; filter:brightness(1.05);}
.btn-ghost{
  background:transparent;
  color:#111827;
  border:1px solid var(--border);
}
.cta-row{display:flex; gap:10px; flex-wrap:wrap;}

.tag-row{display:flex; gap:8px; flex-wrap:wrap; margin-top:10px;}
.tag{
  font-size:12px;
  color:#111827;
  border:1px solid var(--border);
  background:var(--soft);
  padding:4px 8px;
  border-radius:999px;
}

.link-list{margin:10px 0 0; padding:0 0 0 18px;}
.note{margin:12px 0 0; color:var(--muted); font-size:14px;}

.page-head{margin:0 0 18px;}
.page-head h1{margin:0 0 10px; font-size:28px; line-height:1.2;}

.breadcrumbs{
  display:flex;
  gap:8px;
  align-items:center;
  color:var(--muted);
  font-size:14px;
  margin-bottom:14px;
}
.breadcrumbs a{color:var(--muted);}

.content-layout{
  display:grid;
  grid-template-columns: 1.4fr .6fr;
  gap:18px;
  align-items:start;
}
.content{min-width:0;}
.sidebar .sticky{position:sticky; top:78px; display:grid; gap:14px;}

.article-head h1{margin:0 0 10px; font-size:30px; line-height:1.25;}
.article-meta{color:var(--muted); font-size:14px; margin:0 0 10px;}
.article-meta .dot{padding:0 6px;}

.toc{
  margin:18px 0;
  padding:14px 16px;
  background:var(--soft);
  border:1px solid var(--border);
  border-radius:var(--radius);
}
.toc-title{margin:0 0 8px; font-weight:800;}
.toc ol{margin:0; padding-left:18px;}
.toc a{color:#111827; text-decoration:none;}
.toc a:hover{text-decoration:underline;}

.content h2{margin:26px 0 10px; font-size:22px;}
.content h3{margin:18px 0 8px; font-size:18px;}
.content p{margin:10px 0;}
.bullets{margin:10px 0 0; padding-left:18px;}
.steps{margin:10px 0 0; padding-left:18px;}

.callout{
  margin:16px 0;
  padding:12px 14px;
  border-radius:var(--radius);
  border:1px solid var(--border);
  background:#fff;
}
.faq details{
  border:1px solid var(--border);
  border-radius:var(--radius);
  background:#fff;
  padding:12px 14px;
  margin-bottom:10px;
}
.faq summary{cursor:pointer; font-weight:700;}
.faq-body{color:#1f2937; padding-top:6px;}

.pill{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding:10px 12px;
  border-radius:999px;
  border:1px solid var(--border);
  background:var(--soft);
  font-weight:700;
  text-decoration:none;
}
.pill:hover{text-decoration:none; filter:brightness(1.02);}

.site-footer{
  border-top:1px solid var(--border);
  background:#fff;
}
.footer-inner{
  display:flex;
  justify-content:space-between;
  gap:14px;
  padding:22px 0;
  flex-wrap:wrap;
}
.footer-title{margin:0; font-weight:900;}
.footer-nav{display:flex; gap:12px; flex-wrap:wrap;}