:root {
  --rb-ink: #172230;
  --rb-ink-soft: #5c6b7a;
  --rb-ink-faint: #93a1b0;
  --rb-blue: #2563eb;
  --rb-blue-dark: #1d4ed8;
  --rb-blue-soft: #eef4ff;
  --rb-violet: #7c3aed;
  --rb-violet-soft: #f3ecfe;
  --rb-amber: #d97706;
  --rb-amber-soft: #fef3e2;
  --rb-bg: #ffffff;
  --rb-bg-alt: #f7f9fc;
  --rb-panel: #ffffff;
  --rb-border: #e5e9f0;
  --rb-radius: 14px;
  --rb-radius-sm: 8px;
  --rb-shadow: 0 1px 2px rgba(23,34,48,.04), 0 6px 20px rgba(23,34,48,.05);
  --rb-shadow-lg: 0 20px 44px rgba(23,34,48,.10);
  --rb-sans: "Inter", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--rb-sans);
  color: var(--rb-ink);
  background: var(--rb-bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--rb-blue-dark); text-decoration: none; }
a:hover { color: var(--rb-blue); text-decoration: underline; }

/* ---------- header ---------- */
.site-header {
  background: rgba(255,255,255,.88);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--rb-border);
  position: sticky;
  top: 0;
  z-index: 20;
}
.header-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--rb-ink);
  letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; color: var(--rb-ink); }
.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--rb-blue), var(--rb-violet));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 800;
}
.brand-logo { height: 42px; width: auto; display: block; }
.brand-wordmark {
  font-family: 'Playfair Display', 'Palatino Linotype', 'Book Antiqua', Georgia, serif;
  font-weight: 900;
  font-size: 1.5rem;
  color: #3B8DC8;
  letter-spacing: 1px;
  border-bottom: 3px solid #3B8DC8;
  line-height: 1.3;
  padding-bottom: 2px;
}
.top-nav { display: flex; align-items: center; gap: 26px; flex-wrap: wrap; }
.top-nav a {
  color: var(--rb-ink-soft);
  font-size: 0.92rem;
  font-weight: 600;
}
.top-nav a:hover { color: var(--rb-blue-dark); text-decoration: none; }
.top-nav .top-cta {
  background: var(--rb-ink);
  color: #fff !important;
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 0.85rem;
}
.top-nav .top-cta:hover { background: var(--rb-blue-dark); }
.top-nav .lang-switch {
  border: 1px solid var(--rb-border);
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--rb-blue-dark) !important;
}
.top-nav .lang-switch:hover { background: var(--rb-blue-soft); text-decoration: none; }

/* ---------- layout ---------- */
.layout {
  max-width: 1240px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 268px 1fr;
  gap: 28px;
  padding: 32px 24px 72px;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: 84px;
  background: var(--rb-panel);
  border: 1px solid var(--rb-border);
  border-radius: var(--rb-radius);
  padding: 18px;
}
.side-group + .side-group { margin-top: 20px; }
.side-group-title {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--rb-ink-soft);
  font-weight: 700;
  margin-bottom: 10px;
  padding: 0 8px;
}
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li { margin: 2px 0; }
.sidebar a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: var(--rb-radius-sm);
  color: var(--rb-ink);
  font-size: 0.9rem;
  font-weight: 500;
  border-left: 2px solid transparent;
}
.sidebar a::before {
  content: "";
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--rb-ink-faint);
  flex: none;
}
.sidebar a:hover { background: var(--rb-blue-soft); color: var(--rb-blue-dark); text-decoration: none; }
.sidebar a:hover::before { background: var(--rb-blue); }
.sidebar a.active {
  background: var(--rb-blue-soft);
  color: var(--rb-blue-dark);
  border-left-color: var(--rb-blue);
  font-weight: 700;
}
.sidebar a.active::before { background: var(--rb-blue); }

.content {
  background: var(--rb-panel);
  border: 1px solid var(--rb-border);
  border-radius: var(--rb-radius);
  padding: 36px 44px;
  min-width: 0;
}
.breadcrumb {
  font-size: 0.8rem;
  color: var(--rb-ink-soft);
  margin-bottom: 10px;
  font-weight: 600;
}
.content h1 {
  font-size: 1.9rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  margin: 0 0 22px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--rb-border);
  color: var(--rb-ink);
}
.prose { font-size: 0.99rem; color: var(--rb-ink); }
.prose img { max-width: 100%; height: auto; border-radius: var(--rb-radius-sm); border: 1px solid var(--rb-border); }
.prose table { border-collapse: collapse; max-width: 100%; }
.prose .letter2_left, .prose .text4, .prose .text5 {
  font-weight: 700;
  color: var(--rb-ink);
  margin: 26px 0 8px;
  display: block;
  font-size: 1.05rem;
  padding-left: 12px;
  border-left: 3px solid var(--rb-blue);
}
.prose .smallletter { color: var(--rb-blue-dark); }
.prose br + br { display: none; }
.prose a { border-bottom: 1px solid transparent; }
.prose a:hover { border-bottom-color: var(--rb-blue); }

/* ---------- eyebrow / section labels ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--rb-blue-dark);
  margin-bottom: 10px;
}
.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--rb-blue);
}
.eyebrow.violet { color: var(--rb-violet); }
.eyebrow.violet::before { background: var(--rb-violet); }

/* ---------- 3-column guide/symbology index (legacy layout, modern skin) ---------- */
.guide-columns {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0 28px;
  margin: 12px 0 32px;
}
.guide-col-header {
  background: var(--rb-blue-soft);
  color: var(--rb-blue-dark);
  font-weight: 800;
  font-size: 0.98rem;
  padding: 10px 14px;
  border-radius: var(--rb-radius-sm);
  margin-bottom: 14px;
}
.guide-col-header.violet { background: var(--rb-violet-soft); color: var(--rb-violet); }
.guide-subhead {
  font-weight: 700;
  font-size: 0.86rem;
  color: var(--rb-blue-dark);
  margin: 18px 0 6px;
}
.guide-subhead:first-of-type { margin-top: 0; }
.guide-subsubhead {
  font-weight: 600;
  font-size: 0.78rem;
  color: var(--rb-ink-soft);
  margin: 10px 0 4px;
}
.guide-columns ul { list-style: none; margin: 0 0 4px; padding: 0; }
.guide-columns li {
  font-size: 0.86rem;
  padding: 3px 0 3px 16px;
  position: relative;
  border-bottom: 1px dashed var(--rb-border);
}
.guide-columns li::before {
  content: "\00d7";
  position: absolute;
  left: 0;
  color: var(--rb-blue);
  font-weight: 700;
}
.guide-az { display: flex; flex-wrap: wrap; gap: 2px 8px; padding: 3px 0 8px 16px; }
.guide-az a { font-size: 0.86rem; }

@media (max-width: 700px) {
  .guide-columns { grid-template-columns: 1fr; gap: 28px 0; }
}

/* ---------- homepage hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: 96px 24px 64px;
  text-align: center;
  border-bottom: 1px solid var(--rb-border);
  background:
    radial-gradient(560px 320px at 12% -10%, rgba(37,99,235,.12), transparent 60%),
    radial-gradient(560px 320px at 88% 0%, rgba(124,58,237,.10), transparent 60%),
    var(--rb-bg);
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(23,34,48,.06) 1px, transparent 1px);
  background-size: 22px 22px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,.6), transparent 70%);
  mask-image: linear-gradient(180deg, rgba(0,0,0,.6), transparent 70%);
  pointer-events: none;
}
.hero-inner { position: relative; max-width: 900px; margin: 0 auto; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--rb-panel);
  border: 1px solid var(--rb-border);
  box-shadow: var(--rb-shadow);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--rb-ink-soft);
  margin-bottom: 22px;
}
.hero h1 {
  font-size: clamp(2rem, 4.2vw, 2.9rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  color: var(--rb-ink);
}
.hero p {
  font-size: 1.1rem;
  color: var(--rb-ink-soft);
  max-width: 640px;
  margin: 0 auto;
}
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-top: 36px;
  flex-wrap: wrap;
}
.hero-stat strong { display: block; font-size: 1.5rem; font-weight: 800; color: var(--rb-ink); }
.hero-stat span { font-size: 0.82rem; color: var(--rb-ink-soft); }

/* ---------- section shell ---------- */
.section {
  max-width: 1240px;
  margin: 0 auto;
  padding: 56px 24px;
}
.section-head { max-width: 640px; margin: 0 auto 36px; text-align: center; }
.section-head h2 { font-size: 1.6rem; font-weight: 800; margin: 0 0 10px; letter-spacing: -0.01em; }
.section-head p { color: var(--rb-ink-soft); margin: 0; }
.section-alt { background: var(--rb-bg-alt); }

/* ---------- hub / feature cards ---------- */
.hub-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.hub-card {
  display: block;
  background: var(--rb-panel);
  border-radius: var(--rb-radius);
  padding: 30px;
  box-shadow: var(--rb-shadow);
  border: 1px solid var(--rb-border);
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}
.hub-card:hover {
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: var(--rb-shadow-lg);
  border-color: var(--rb-blue);
}
.icon-badge {
  width: 46px;
  height: 46px;
  border-radius: 12px;
  background: var(--rb-blue-soft);
  color: var(--rb-blue-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.icon-badge.violet { background: var(--rb-violet-soft); color: var(--rb-violet); }
.icon-badge.amber { background: var(--rb-amber-soft); color: var(--rb-amber); }
.icon-badge svg { width: 22px; height: 22px; }
.hub-card h2, .hub-card h3 { margin: 0 0 8px; font-size: 1.15rem; color: var(--rb-ink); font-weight: 800; }
.hub-card p { margin: 0; color: var(--rb-ink-soft); font-size: 0.94rem; }
.hub-card .card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 14px;
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--rb-blue-dark);
}

/* category card grid (used on barcode/biometrics hub pages) */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  margin: 20px 0 32px;
}
.cat-card {
  border: 1px solid var(--rb-border);
  border-radius: var(--rb-radius-sm);
  padding: 20px;
  background: var(--rb-panel);
}
.cat-card h3 {
  margin: 0 0 10px;
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--rb-ink);
  display: flex;
  align-items: center;
  gap: 8px;
}
.cat-card h3 .icon-badge { width: 30px; height: 30px; border-radius: 8px; margin: 0; }
.cat-card h3 .icon-badge svg { width: 16px; height: 16px; }
.cat-card ul { list-style: none; margin: 0; padding: 0; columns: 1; }
.cat-card li { margin: 4px 0; font-size: 0.88rem; }
.cat-card .cat-desc { color: var(--rb-ink-soft); font-size: 0.85rem; margin: 0 0 12px; }

/* four-column software grid on homepage */
.soft-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}
.soft-card {
  border: 1px solid var(--rb-border);
  border-radius: var(--rb-radius-sm);
  padding: 20px;
  background: var(--rb-panel);
}
.soft-card h3 { margin: 0 0 4px; font-size: 0.95rem; font-weight: 700; }
.soft-card .cat-desc { margin: 0 0 12px; }
.soft-card ul { list-style: none; margin: 0; padding: 0; }
.soft-card li { margin: 5px 0; font-size: 0.85rem; }
.soft-card li a::before { content: "→ "; color: var(--rb-ink-faint); }

.cta-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  background: linear-gradient(135deg, var(--rb-ink) 0%, #26344a 100%);
  color: #fff;
  border-radius: var(--rb-radius);
  padding: 32px 36px;
}
.cta-banner h3 { margin: 0 0 6px; font-size: 1.2rem; font-weight: 800; }
.cta-banner p { margin: 0; color: rgba(255,255,255,.72); font-size: 0.94rem; }
.cta-banner .card-link { background: #fff; color: var(--rb-ink); padding: 10px 20px; border-radius: 999px; font-weight: 700; font-size: 0.88rem; }
.cta-banner .card-link:hover { background: var(--rb-blue-soft); text-decoration: none; }

/* ---------- legacy links archive ---------- */
.legacy-links {
  margin-top: 36px;
  padding-top: 14px;
  border-top: 1px dashed var(--rb-border);
}
.legacy-links summary {
  cursor: pointer;
  font-size: 0.76rem;
  color: var(--rb-ink-faint);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.legacy-links ul { list-style: none; margin: 8px 0 0; padding: 0; }
.legacy-links li {
  font-size: 0.76rem;
  color: var(--rb-ink-faint);
  margin: 3px 0;
}
.legacy-links li .dead-url { text-decoration: line-through; color: var(--rb-ink-faint); }

/* ---------- footer ---------- */
.site-footer {
  background: var(--rb-bg-alt);
  border-top: 1px solid var(--rb-border);
  margin-top: 0;
}
.footer-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 22px 24px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--rb-ink-soft);
}
.footer-inner a { color: var(--rb-ink-soft); }
.footer-inner a:hover { color: var(--rb-blue-dark); }

@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .content { padding: 26px 22px; }
  .hub-cards { grid-template-columns: 1fr; }
  .hero { padding: 64px 20px 48px; }
  .section { padding: 40px 20px; }
}