/* adv-b2b — B2B ad-tech (navy, geometric hero, enterprise cards, FAQ) */
:root {
  --bg: #f0f4f8;
  --surface: #ffffff;
  --text: #0a1628;
  --muted: #4a5568;
  --border: #cbd5e0;
  --primary: #1a365d;
  --primary-light: #2c5282;
  --accent: #3182ce;
  --navy-dark: #0d2137;
  --max: 1000px;
  --radius: 8px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}
img { max-width: 100%; height: auto; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--primary-light); text-decoration: underline; }

.skip-link { position: absolute; left: -9999px; top: 0; background: var(--primary); color: #fff; padding: 0.5rem 1rem; z-index: 100; }
.skip-link:focus { left: 1rem; top: 1rem; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }
.site-main { padding-bottom: 3rem; }

.site-header { background: var(--navy-dark); border-bottom: 3px solid var(--accent); }
.header-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 0.75rem; min-height: 3.75rem; }
.brand { font-weight: 700; font-size: 1rem; color: #fff; text-decoration: none; letter-spacing: 0.02em; }
.site-nav ul { display: flex; flex-wrap: wrap; gap: 0.25rem 1.25rem; list-style: none; margin: 0; padding: 0; }
.site-nav a { color: #a0aec0; text-decoration: none; font-weight: 500; font-size: 0.88rem; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: #fff; }
.nav-toggle { display: none; border: 1px solid #4a5568; background: transparent; border-radius: 6px; padding: 0.45rem; cursor: pointer; }
.nav-toggle span { display: block; width: 18px; height: 2px; background: #fff; margin: 4px 0; }

.demo-banner { background: #ebf4ff; border-bottom: 1px solid var(--border); padding: 0.6rem 0; font-size: 0.85rem; color: var(--muted); }

.hero-b2b { background: var(--navy-dark); color: #fff; padding: 3.5rem 0; position: relative; overflow: hidden; }
.geo-accent { position: absolute; right: -60px; top: -60px; width: 280px; height: 280px; background: linear-gradient(135deg, var(--accent) 0%, transparent 70%); opacity: 0.25; clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%); }
.hero-b2b .wrap { position: relative; z-index: 1; }
.hero-b2b h1 { margin: 0.35rem 0 0.75rem; font-size: clamp(1.6rem, 4vw, 2.4rem); line-height: 1.2; font-weight: 700; max-width: 28rem; }
.hero-b2b .eyebrow { color: var(--accent); }
.hero-b2b .lead { color: #cbd5e0; max-width: 32rem; }
.eyebrow { font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.14em; margin: 0; }
.lead { font-size: 1.02rem; margin: 0; }

.section-block { padding: 2.5rem 0; }
.section-block.alt-band { background: var(--surface); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-head h2 { margin: 0 0 0.35rem; font-size: 1.35rem; color: var(--primary); font-weight: 700; }
.section-sub { color: var(--muted); margin: 0 0 1.5rem; font-size: 0.92rem; }

.b2b-diagram { display: grid; grid-template-columns: 1fr auto 1fr; gap: 1rem; align-items: center; text-align: center; }
.node { background: var(--surface); border: 2px solid var(--border); border-radius: var(--radius); padding: 1.25rem; font-weight: 600; font-size: 0.92rem; }
.node.center { background: var(--primary); color: #fff; border-color: var(--primary); }
.b2b-diagram .node:not(.center)::after { content: "→"; position: absolute; display: none; }

.b2b-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; }
.b2b-cards article { background: var(--bg); border: 1px solid var(--border); border-left: 4px solid var(--accent); border-radius: var(--radius); padding: 1.35rem; }
.b2b-cards h3 { margin: 0 0 0.4rem; font-size: 1rem; color: var(--primary); }
.b2b-cards p { margin: 0; color: var(--muted); font-size: 0.9rem; }

.faq-block { padding: 2.5rem 0; }
.faq-block h2 { font-size: 1.25rem; color: var(--primary); margin: 0 0 1rem; }
.faq-block details { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 0.5rem; }
.faq-block summary { padding: 1rem 1.15rem; font-weight: 600; cursor: pointer; color: var(--text); list-style: none; }
.faq-block summary::-webkit-details-marker { display: none; }
.faq-block summary::before { content: "+ "; color: var(--accent); font-weight: 700; }
.faq-block details[open] summary::before { content: "− "; }
.faq-block details p { margin: 0; padding: 0 1.15rem 1rem; color: var(--muted); font-size: 0.92rem; }

.page-hero { background: var(--surface); border-bottom: 1px solid var(--border); padding: 2.5rem 0; }
.page-hero h1 { margin: 0.35rem 0 0.75rem; font-size: clamp(1.5rem, 4vw, 2rem); color: var(--primary); }
.content-section { padding: 2rem 0; }

.prose h2 { font-size: 1.2rem; color: var(--primary); margin-top: 1.5rem; }
.prose p, .prose li { color: var(--muted); }

.contact-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; }
.contact-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; }
.contact-card h2 { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--accent); margin: 1rem 0 0.25rem; font-weight: 700; }
.contact-card h2:first-child { margin-top: 0; }
.muted-card { background: var(--bg); }
.text-link { font-weight: 600; }

.site-footer { background: var(--navy-dark); color: #a0aec0; margin-top: 2rem; }
.footer-inner { padding: 2rem 0; }
.footer-brand strong { color: #fff; }
.footer-brand p { margin: 0.35rem 0 0; font-size: 0.85rem; }
.footer-links { display: flex; flex-wrap: wrap; gap: 0.75rem 1.25rem; margin: 1rem 0; }
.footer-links a { color: #a0aec0; text-decoration: none; font-size: 0.85rem; }
.footer-links a:hover { color: #fff; }
.footer-copy { margin: 0; font-size: 0.8rem; color: #718096; }
.muted { color: var(--muted); }

.text-link { color: var(--accent); font-weight: 600; }
.footer-inner { padding: 2rem 0; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.b2b-diagram .node { position: relative; transition: border-color 0.15s; }
.b2b-diagram .node:hover { border-color: var(--accent); }
.b2b-cards article:hover { border-left-color: var(--primary); background: var(--surface); }
.faq-block details[open] { border-color: var(--accent); }
.faq-block details[open] summary { color: var(--accent); }

.contact-card p { margin: 0; }
.prose a { color: var(--accent); font-weight: 500; }
.prose ul { padding-left: 1.25rem; }
.hero-b2b .wrap { padding-top: 0.5rem; padding-bottom: 0.5rem; }

@media (min-width: 721px) {
  .b2b-diagram { max-width: 640px; margin: 0 auto; }
  .b2b-diagram .node:not(.center)::before { content: ""; position: absolute; top: 50%; width: 1rem; height: 2px; background: var(--border); }
}

@media (max-width: 720px) {
  .nav-toggle { display: block; }
  .site-nav { display: none; width: 100%; }
  .site-nav.is-open { display: block; }
  .site-nav ul { flex-direction: column; padding: 0.5rem 0; }
  .b2b-diagram { grid-template-columns: 1fr; }
  .hero-b2b { padding: 2.5rem 0; }
  .geo-accent { width: 180px; height: 180px; right: -40px; top: -40px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .b2b-diagram .node { transition: none; }
}

/* Shared utilities & a11y enhancements */
.site-main { min-height: 50vh; }
.header-inner.wrap, .footer-inner.wrap { padding-left: 0; padding-right: 0; }
.site-nav a:focus-visible { outline: 2px solid currentColor; outline-offset: 2px; border-radius: 2px; }
.demo-banner strong { font-weight: 700; }
.content-section .prose { max-width: 42rem; }
.page-hero .eyebrow + h1 { margin-top: 0.35rem; }
.contact-grid .contact-card h2 + p { line-height: 1.5; }

@media (prefers-contrast: more) {
  :root { --border: currentColor; }
  .site-header, .site-footer, .contact-card, .deal-card, .saas-card, .catalog-card, .stat-card, .panel, .mod, .link-row { border-width: 2px; }
}

@media print {
  .skip-link, .nav-toggle, .demo-banner, .site-nav { display: none !important; }
  .site-header { position: static; border-bottom: 1px solid #000; }
  body { background: #fff; color: #000; font-size: 11pt; }
  a { color: #000; text-decoration: underline; }
}