:root {
  --ink: #17202a;
  --muted: #5b6572;
  --line: #d9e0e8;
  --soft: #f5f8fb;
  --accent: #0a6f72;
  --accent-2: #945f16;
  --paper: #ffffff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.7;
  background: var(--paper);
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px clamp(20px, 5vw, 72px);
  border-bottom: 1px solid var(--line);
  background: #fff;
}

.brand {
  color: var(--ink);
  font-weight: 700;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 14px;
}

.nav a { color: var(--muted); }
.nav a.active { color: var(--accent); font-weight: 700; }

.hero {
  padding: clamp(54px, 8vw, 96px) clamp(20px, 5vw, 72px) clamp(42px, 6vw, 68px);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, #fff, var(--soft));
}

.hero-home {
  background:
    linear-gradient(180deg, rgba(255,255,255,.96), rgba(245,248,251,.98)),
    repeating-linear-gradient(90deg, #e5edf4 0, #e5edf4 1px, transparent 1px, transparent 44px);
}

.kicker {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
}

h1 {
  max-width: 980px;
  margin: 0;
  font-size: clamp(34px, 5vw, 58px);
  line-height: 1.08;
}

.hero p:last-child {
  max-width: 860px;
  margin: 20px 0 0;
  color: var(--muted);
  font-size: 19px;
}

.article {
  max-width: 1040px;
  padding: clamp(40px, 6vw, 72px) clamp(20px, 5vw, 72px);
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 42px;
}

.stats div,
.qa-card,
.reference-box,
.topic-link {
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #fff;
}

.stats div {
  padding: 18px;
}

.stats strong,
.stats span {
  display: block;
}

.stats strong {
  color: var(--accent);
  font-size: 34px;
  line-height: 1;
}

.stats span {
  margin-top: 8px;
  color: var(--muted);
}

.article-section {
  margin-bottom: 44px;
}

h2 {
  margin: 0 0 14px;
  font-size: clamp(24px, 3vw, 32px);
  line-height: 1.2;
}

.qa-card {
  margin-bottom: 18px;
  padding: 24px;
}

.qa-card p,
.qa-card li,
.topic-link span,
.reference-box p,
.glossary dd {
  color: var(--muted);
  font-size: 16px;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.topic-link {
  display: block;
  min-height: 128px;
  padding: 18px;
}

.topic-link strong,
.topic-link span {
  display: block;
}

.topic-link strong {
  margin-bottom: 8px;
  color: var(--ink);
}

.reference-box {
  margin: 34px 0 0;
  padding: 22px;
  border-left: 4px solid var(--accent-2);
  background: var(--soft);
}

.related {
  margin-top: 48px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.related ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 24px;
  padding-left: 20px;
}

.glossary {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 14px 24px;
}

.glossary dt {
  font-weight: 700;
}

.glossary dd {
  margin: 0;
}

.footer {
  padding: 32px clamp(20px, 5vw, 72px);
  background: #111820;
}

.footer p {
  max-width: 900px;
  color: #b9c6d3;
}

.footer a { color: #fff; }

@media (max-width: 760px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .stats,
  .topic-grid,
  .related ul,
  .glossary {
    grid-template-columns: 1fr;
  }
}