:root {
  --ink: #0f172a;
  --muted: #475569;
  --line: #e2e8f0;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --surface: #f8fafc;
  --ok: #059669;
  --warn: #d97706;
  --bad: #dc2626;
  --radius: 12px;
  --max: 760px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Plus Jakarta Sans', system-ui, sans-serif;
  color: #334155;
  background: #fff;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand); text-decoration: none; font-weight: 600; }
a:hover { color: var(--brand-dark); text-decoration: underline; }

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  font-weight: 700;
}
.nav-logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
}
.nav-links { display: flex; gap: 8px; list-style: none; flex-wrap: wrap; }
.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  padding: 8px 12px;
  border-radius: 8px;
  text-decoration: none;
}
.nav-links a:hover { background: var(--surface); color: var(--ink); text-decoration: none; }

.kb-hero {
  background: linear-gradient(180deg, #eff6ff 0%, #fff 100%);
  border-bottom: 1px solid var(--line);
  padding: 48px 24px 40px;
}
.kb-hero-inner { max-width: var(--max); margin: 0 auto; }
.kb-breadcrumb {
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 16px;
}
.kb-breadcrumb a { font-weight: 500; }
.kb-cat {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--brand);
  background: #dbeafe;
  padding: 4px 10px;
  border-radius: 6px;
  margin-bottom: 12px;
}
.kb-hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -.02em;
  line-height: 1.2;
  margin-bottom: 16px;
}
.kb-lead { font-size: 1.125rem; color: var(--muted); max-width: 62ch; }
.kb-meta { font-size: 14px; color: var(--muted); margin-top: 20px; }

.kb-layout {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 24px 80px;
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 48px;
  align-items: start;
}

@media (max-width: 900px) {
  .kb-layout { grid-template-columns: 1fr; }
  .kb-toc { order: -1; }
  .nav-links { display: none; }
}

.kb-article h2 {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--ink);
  margin: 2.5rem 0 1rem;
  padding-top: .5rem;
  scroll-margin-top: 80px;
}
.kb-article h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--ink);
  margin: 1.75rem 0 .75rem;
}
.kb-article p { margin-bottom: 1rem; }
.kb-article ul, .kb-article ol { margin: 0 0 1rem 1.25rem; }
.kb-article li { margin-bottom: .5rem; }

.kb-checklist { list-style: none; margin-left: 0; }
.kb-checklist li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  margin-bottom: 8px;
  background: #fff;
}
.kb-checklist .mark { flex-shrink: 0; font-weight: 700; }
.kb-checklist .ok { color: var(--ok); }
.kb-checklist .bad { color: var(--bad); }
.kb-checklist .warn { color: var(--warn); }

.kb-callout {
  padding: 16px 18px;
  border-radius: var(--radius);
  margin: 1.5rem 0;
  border-left: 4px solid var(--brand);
  background: #eff6ff;
  font-size: 15px;
}
.kb-callout-warn {
  border-left-color: var(--warn);
  background: #fffbeb;
}
.kb-callout strong { display: block; color: var(--ink); margin-bottom: 6px; }

.kb-table-wrap { overflow-x: auto; margin: 1.5rem 0; }
table.kb-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.kb-table th, .kb-table td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
}
.kb-table th { background: var(--surface); font-weight: 700; color: var(--ink); }

.kb-toc {
  position: sticky;
  top: 88px;
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 14px;
}
.kb-toc h2 { font-size: 13px; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); margin: 0 0 12px; }
.kb-toc ol { margin: 0; padding-left: 1.1rem; }
.kb-toc a { font-weight: 500; color: var(--muted); text-decoration: none; }
.kb-toc a:hover { color: var(--brand); }

.kb-cta {
  margin-top: 3rem;
  padding: 28px;
  background: linear-gradient(135deg, #eff6ff, #f0fdf4);
  border: 1px solid #bfdbfe;
  border-radius: var(--radius);
}
.kb-cta h2 { margin-top: 0; font-size: 1.2rem; }
.kb-cta p { margin-bottom: 16px; color: var(--muted); }
.kb-btn {
  display: inline-block;
  background: var(--brand);
  color: #fff !important;
  padding: 12px 20px;
  border-radius: 10px;
  font-weight: 600;
  text-decoration: none !important;
}
.kb-btn:hover { background: var(--brand-dark); }
.kb-btn-ghost {
  background: #fff;
  color: var(--ink) !important;
  border: 1px solid var(--line);
  margin-left: 8px;
}

.kb-footer {
  border-top: 1px solid var(--line);
  padding: 32px 24px;
  text-align: center;
  font-size: 14px;
  color: var(--muted);
}

.kb-related { margin-top: 2rem; padding-top: 2rem; border-top: 1px solid var(--line); }
.kb-related ul { list-style: none; margin: 0; padding: 0; }
.kb-related li { margin-bottom: 8px; }