:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #3b82f6;
  --accent: #06b6d4;
  --bg: #ffffff;
  --bg-soft: #f6f8fc;
  --bg-dark: #0f172a;
  --text: #1e293b;
  --text-soft: #64748b;
  --border: #e2e8f0;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(15, 23, 42, .08);
  --shadow-sm: 0 4px 14px rgba(15, 23, 42, .06);
  --maxw: 1180px;
  --font: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }
.muted { color: var(--text-soft); }
.center { text-align: center; }
.section { padding: 80px 0; }
.section-soft { background: var(--bg-soft); }
h1, h2, h3, h4 { line-height: 1.25; font-weight: 700; }
h2.title { font-size: 32px; margin-bottom: 12px; }
.lead { font-size: 18px; color: var(--text-soft); max-width: 720px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: 999px; font-weight: 600;
  font-size: 15px; cursor: pointer; border: 1px solid transparent;
  transition: transform .15s ease, box-shadow .15s ease, background .15s ease;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 8px 20px rgba(37,99,235,.3); }
.btn-primary:hover { background: var(--primary-dark); }
.btn-ghost { background: #fff; color: var(--primary); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--primary); }
.btn-lg { padding: 15px 32px; font-size: 16px; }

/* ---------- Navbar ---------- */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.88); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.navbar .inner { display: flex; align-items: center; justify-content: space-between; height: 66px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; }
.brand img { width: 34px; height: 34px; border-radius: 8px; }
.brand small { display: block; font-size: 11px; font-weight: 500; color: var(--text-soft); }
.nav-links { display: flex; gap: 28px; align-items: center; }
.nav-links a { font-size: 15px; color: var(--text); font-weight: 500; position: relative; }
.nav-links a:hover { color: var(--primary); }
.nav-links a.active { color: var(--primary); }
.nav-toggle { display: none; background: none; border: none; font-size: 26px; cursor: pointer; }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: 96px 0 80px; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(700px 360px at 80% -10%, rgba(37,99,235,.16), transparent 60%),
    radial-gradient(600px 320px at 0% 10%, rgba(6,182,212,.14), transparent 55%);
}
.hero h1 { font-size: 46px; letter-spacing: -.5px; margin-bottom: 18px; }
.hero h1 .hl { color: var(--primary); }
.hero .lead { margin: 0 auto 30px; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.badges { display: flex; gap: 10px; justify-content: center; margin-top: 28px; flex-wrap: wrap; }
.badge { background: #fff; border: 1px solid var(--border); border-radius: 999px; padding: 6px 14px; font-size: 13px; color: var(--text-soft); box-shadow: var(--shadow-sm); }

/* ---------- Feature grid ---------- */
.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow-sm); transition: transform .15s ease, box-shadow .15s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.card .ico { width: 48px; height: 48px; border-radius: 12px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--primary), var(--accent)); color: #fff; font-size: 22px; margin-bottom: 16px; }
.card h3 { font-size: 18px; margin-bottom: 8px; }
.card p { color: var(--text-soft); font-size: 15px; }

/* ---------- Steps ---------- */
.steps { counter-reset: step; }
.step { display: flex; gap: 18px; align-items: flex-start; padding: 16px 0; }
.step .num { flex: 0 0 42px; height: 42px; border-radius: 50%; background: var(--primary); color: #fff;
  display: grid; place-items: center; font-weight: 700; }
.step h4 { font-size: 17px; margin-bottom: 4px; }
.step p { color: var(--text-soft); font-size: 15px; }

/* ---------- Doc layout ---------- */
.doc-layout { display: grid; grid-template-columns: 240px 1fr; gap: 40px; align-items: start; }
.doc-nav { position: sticky; top: 86px; border-right: 1px solid var(--border); padding-right: 16px; }
.doc-nav a { display: block; padding: 8px 12px; border-radius: 8px; color: var(--text-soft); font-size: 14px; }
.doc-nav a:hover, .doc-nav a.active { background: var(--bg-soft); color: var(--primary); font-weight: 600; }
.doc-content h2 { font-size: 26px; margin: 34px 0 12px; padding-top: 8px; }
.doc-content h3 { font-size: 19px; margin: 24px 0 8px; }
.doc-content p, .doc-content li { color: #334155; }
.doc-content ul { padding-left: 22px; margin: 8px 0; }
.doc-content table { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 14px; }
.doc-content th, .doc-content td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; }
.doc-content th { background: var(--bg-soft); }
pre { background: #0f172a; color: #e2e8f0; padding: 16px 18px; border-radius: 10px; overflow: auto; font-size: 13.5px; line-height: 1.6; margin: 12px 0; }
code { font-family: "JetBrains Mono", Consolas, Menlo, monospace; }
:not(pre) > code { background: var(--bg-soft); padding: 2px 6px; border-radius: 6px; font-size: 13px; color: #b91c1c; }
.callout { border-left: 4px solid var(--primary); background: var(--bg-soft); padding: 14px 16px; border-radius: 0 10px 10px 0; margin: 14px 0; font-size: 15px; }
.callout.warn { border-color: #f59e0b; background: #fffbeb; }

/* ---------- Pricing ---------- */
.price-card { text-align: center; }
.price-card .price { font-size: 42px; font-weight: 800; color: var(--primary); margin: 8px 0; }
.price-card .price span { font-size: 16px; color: var(--text-soft); font-weight: 500; }
.price-card ul { list-style: none; text-align: left; margin: 16px auto; max-width: 260px; }
.price-card li { padding: 6px 0; color: var(--text-soft); }
.price-card li::before { content: "✓"; color: #16a34a; font-weight: 700; margin-right: 8px; }

/* ---------- Footer ---------- */
.footer { background: var(--bg-dark); color: #cbd5e1; padding: 50px 0 28px; }
.footer .cols { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 30px; }
.footer h4 { color: #fff; font-size: 16px; margin-bottom: 14px; }
.footer a { color: #cbd5e1; font-size: 14px; display: block; padding: 4px 0; }
.footer a:hover { color: #fff; }
.footer .brand { color: #fff; }
.footer .copy { border-top: 1px solid #1e293b; margin-top: 34px; padding-top: 18px; font-size: 13px; color: #94a3b8; text-align: center; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .doc-layout { grid-template-columns: 1fr; }
  .doc-nav { position: static; border-right: none; border-bottom: 1px solid var(--border); padding-bottom: 12px; margin-bottom: 18px; }
  .footer .cols { grid-template-columns: 1fr 1fr; }
  .hero h1 { font-size: 34px; }
  .nav-links { display: none; position: absolute; top: 66px; left: 0; right: 0; background: #fff;
    flex-direction: column; gap: 0; padding: 10px 20px; border-bottom: 1px solid var(--border); box-shadow: var(--shadow); }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 0; border-bottom: 1px solid var(--bg-soft); }
  .nav-toggle { display: block; }
}