/* 28B Labs - site stylesheet */
:root {
  --navy: #030351;
  --blue: #1d2cf3;
  --blue-dark: #121cb8;
  --sky: #eef0ff;
  --ink: #16182b;
  --muted: #555a73;
  --line: #e2e4f0;
  --white: #ffffff;
  --radius: 14px;
  --max: 1120px;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

img, svg { max-width: 100%; }

a { color: var(--blue); }
a:hover { color: var(--navy); }

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--navy);
  color: var(--white);
  padding: 10px 16px;
  z-index: 100;
}
.skip-link:focus { left: 12px; top: 12px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 70px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--navy);
  text-decoration: none;
}
.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--blue);
  color: var(--white);
  font-size: 0.95rem;
  font-weight: 800;
}
.main-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.main-nav a {
  display: block;
  padding: 8px 14px;
  border-radius: 999px;
  color: var(--ink);
  font-weight: 600;
  font-size: 0.97rem;
  text-decoration: none;
  transition: background 0.15s, color 0.15s;
}
.main-nav a:hover { background: var(--sky); color: var(--blue); }
.main-nav a[aria-current="page"] { background: var(--blue); color: var(--white); }

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--blue) 100%);
  color: var(--white);
  padding: 96px 0 88px;
}
.hero.hero-sm { padding: 72px 0 64px; }
.eyebrow {
  display: inline-block;
  margin: 0 0 14px;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.14);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0 0 18px;
  max-width: 820px;
  font-size: clamp(2.1rem, 5vw, 3.4rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
}
.hero p.lead {
  margin: 0;
  max-width: 680px;
  font-size: 1.18rem;
  color: rgba(255, 255, 255, 0.88);
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }

.btn {
  display: inline-block;
  padding: 13px 24px;
  border-radius: 999px;
  font-weight: 700;
  text-decoration: none;
  border: 2px solid transparent;
  transition: transform 0.15s, background 0.15s, color 0.15s;
}
.btn:hover { transform: translateY(-1px); }
.btn-light { background: var(--white); color: var(--navy); }
.btn-light:hover { color: var(--blue); }
.btn-outline { border-color: rgba(255, 255, 255, 0.6); color: var(--white); }
.btn-outline:hover { background: rgba(255, 255, 255, 0.12); color: var(--white); }
.btn-primary { background: var(--blue); color: var(--white); }
.btn-primary:hover { background: var(--blue-dark); color: var(--white); }

/* Sections */
.section { padding: 80px 0; }
.section-alt { background: var(--sky); }
.section h2 {
  margin: 0 0 14px;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--navy);
}
.section-intro { max-width: 720px; margin: 0 0 40px; color: var(--muted); font-size: 1.08rem; }
.section h3 { margin: 0 0 8px; font-size: 1.2rem; color: var(--navy); }

.grid { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
}
.card p { margin: 0; color: var(--muted); }
.card .num {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 16px;
  border-radius: 12px;
  background: var(--sky);
  color: var(--blue);
  font-weight: 800;
}

.split { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: start; }

.checklist { list-style: none; margin: 0; padding: 0; }
.checklist li {
  position: relative;
  padding: 0 0 12px 32px;
}
.checklist li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--blue) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath fill='none' stroke='%23fff' stroke-width='2.4' d='M4 8.5l2.6 2.5L12 5.5'/%3E%3C/svg%3E") center / 14px no-repeat;
}

.cta-band {
  background: var(--navy);
  color: var(--white);
  border-radius: var(--radius);
  padding: 48px;
  text-align: center;
}
.cta-band h2 { color: var(--white); }
.cta-band p { max-width: 620px; margin: 0 auto 26px; color: rgba(255, 255, 255, 0.85); }

/* Prose (blog, terms) */
.prose { max-width: 760px; }
.prose h2 { margin-top: 48px; }
.prose h2:first-child { margin-top: 0; }
.prose p, .prose li { color: #2c2f45; }
.prose ul { padding-left: 22px; }

.post {
  padding: 40px 0;
  border-bottom: 1px solid var(--line);
}
.post:first-of-type { padding-top: 0; }
.post:last-of-type { border-bottom: 0; }
.post-meta { margin: 0 0 14px; font-size: 0.9rem; color: var(--muted); }
.post h2 { margin-top: 0; }

.contact-list { list-style: none; margin: 0; padding: 0; }
.contact-list li { margin-bottom: 18px; }
.contact-list strong { display: block; color: var(--navy); }

/* Footer */
.site-footer {
  background: var(--navy);
  color: rgba(255, 255, 255, 0.8);
  padding: 56px 0 28px;
  font-size: 0.95rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 32px;
  padding-bottom: 32px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
}
.site-footer .brand { color: var(--white); margin-bottom: 12px; }
.footer-title { margin: 0 0 12px; font-weight: 700; color: var(--white); }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: 8px; }
.site-footer a { color: rgba(255, 255, 255, 0.8); text-decoration: none; }
.site-footer a:hover { color: var(--white); text-decoration: underline; }
.social { display: flex; gap: 12px; margin-top: 16px; }
.social a {
  display: inline-grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
}
.social a:hover { background: var(--blue); text-decoration: none; }
.social svg { width: 18px; height: 18px; fill: currentColor; }
.copyright { margin: 24px 0 0; font-size: 0.85rem; color: rgba(255, 255, 255, 0.6); }

/* Responsive */
@media (max-width: 900px) {
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .split { grid-template-columns: 1fr; gap: 32px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  .site-header .container { flex-direction: column; align-items: stretch; gap: 6px; padding-top: 10px; padding-bottom: 10px; }
  .brand { justify-content: center; }
  .main-nav ul { justify-content: center; gap: 2px; }
  .main-nav a { padding: 6px 11px; font-size: 0.92rem; }
  .hero { padding: 64px 0 56px; }
  .section { padding: 56px 0; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .cta-band { padding: 32px 22px; }
}