/* R&D Binder marketing site, v0 (W1 day 3 first draft).
   Design tokens kept aligned with the binder PDF for brand cohesion. */

:root {
  --ink: #0f172a;
  --paper: #ffffff;
  --rule: #cbd5e1;
  --rule-soft: #e2e8f0;
  --accent: #1e3a8a;
  --accent-strong: #172554;
  --muted: #475569;
  --soft: #f8fafc;
  --warn-bg: #fef3c7;
  --warn-border: #b45309;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}
a:hover { color: var(--accent-strong); }

h1, h2, h3, h4 {
  font-family: Georgia, "Times New Roman", serif;
  color: var(--ink);
  letter-spacing: -0.005em;
  margin-top: 0;
}

.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 32px;
}

header.site-header {
  border-bottom: 1px solid var(--rule-soft);
  padding: 20px 0;
  font-size: 14.5px;
}
header.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
header.site-header .brand {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 22px;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
}
header.site-header nav a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 22px;
  font-weight: 500;
}
header.site-header nav a:hover { color: var(--accent); }

section.hero {
  padding: 88px 0 72px;
  border-bottom: 1px solid var(--rule-soft);
}
section.hero h1 {
  font-size: 52px;
  line-height: 1.08;
  margin: 0 0 24px;
  max-width: 880px;
}
section.hero p.lead {
  font-size: 21px;
  line-height: 1.5;
  color: var(--muted);
  max-width: 760px;
  margin: 0 0 36px;
}
.cta-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 8px;
}
.cta {
  display: inline-block;
  padding: 14px 26px;
  border-radius: 4px;
  font-weight: 600;
  font-size: 16px;
  text-decoration: none;
  border: 2px solid transparent;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.cta-primary {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
}
.cta-primary:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #ffffff;
}
.cta-secondary {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}
.cta-secondary:hover {
  background: var(--soft);
  color: var(--accent-strong);
}

section.section {
  padding: 72px 0;
  border-bottom: 1px solid var(--rule-soft);
}
section.section h2 {
  font-size: 34px;
  margin: 0 0 16px;
}
section.section p.section-lead {
  font-size: 18px;
  color: var(--muted);
  max-width: 720px;
  margin: 0 0 40px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.step {
  background: var(--soft);
  border: 1px solid var(--rule-soft);
  border-left: 3px solid var(--accent);
  padding: 22px 24px;
  border-radius: 4px;
}
.step .num {
  display: inline-block;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 14px;
  color: var(--muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.step h3 {
  font-size: 20px;
  margin: 0 0 8px;
}
.step p {
  margin: 0;
  font-size: 15.5px;
  color: var(--muted);
}

.tier {
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 28px;
  background: var(--paper);
}
.tier.featured {
  border-color: var(--accent);
  border-width: 2px;
  position: relative;
}
.tier.featured::before {
  content: "Most common";
  position: absolute;
  top: -12px;
  left: 24px;
  background: var(--accent);
  color: #ffffff;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 3px;
}
.tier h3 {
  font-size: 22px;
  margin: 0 0 6px;
}
.tier .price {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 38px;
  color: var(--ink);
  margin: 12px 0 4px;
}
.tier .price-meta {
  font-size: 14px;
  color: var(--muted);
  margin: 0 0 18px;
}
.tier ul {
  margin: 0;
  padding: 0 0 0 18px;
  font-size: 15px;
}
.tier ul li { margin: 6px 0; color: var(--muted); }

.pilot-banner {
  background: var(--warn-bg);
  border-left: 3px solid var(--warn-border);
  padding: 16px 20px;
  border-radius: 4px;
  margin: 28px 0 0;
  font-size: 15.5px;
  color: #78350f;
}
.pilot-banner strong { color: var(--warn-border); }

.faq dt {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 19px;
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 8px;
}
.faq dd {
  margin: 0 0 28px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.55;
}

footer.site-footer {
  padding: 36px 0 56px;
  font-size: 14px;
  color: var(--muted);
}
footer.site-footer p { margin: 6px 0; }
footer.site-footer a { color: var(--muted); }

@media (max-width: 760px) {
  body { font-size: 16px; }
  section.hero { padding: 56px 0 48px; }
  section.hero h1 { font-size: 36px; }
  section.hero p.lead { font-size: 18px; }
  section.section { padding: 56px 0; }
  section.section h2 { font-size: 28px; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  header.site-header .wrap { flex-direction: column; align-items: flex-start; gap: 12px; }
  header.site-header nav a { margin: 0 16px 0 0; }
}