:root {
  color-scheme: dark;
  --bg: #0A1628;
  --bg-soft: #0F1D32;
  --card: #1E293B;
  --line: #334155;
  --text: #F8FAFC;
  --muted: #94A3B8;
  --accent: #22D3EE;
  --cta: #F97316;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.8;
}

a {
  color: inherit;
}

.site-header,
.site-footer {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-size: 24px;
  font-weight: 800;
  text-decoration: none;
}

.nav-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}

.nav-link:hover {
  color: var(--accent);
}

.hero {
  background: linear-gradient(180deg, #0A1628 0%, #0F2847 100%);
  border-bottom: 1px solid var(--line);
}

.hero-inner,
.content,
.cards {
  max-width: 960px;
  margin: 0 auto;
  padding: 48px 24px;
}

.eyebrow {
  color: var(--accent);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
}

h1 {
  font-size: clamp(32px, 6vw, 56px);
  line-height: 1.15;
  margin: 12px 0 20px;
}

h2 {
  font-size: clamp(24px, 4vw, 34px);
  line-height: 1.25;
  margin: 48px 0 16px;
}

h3 {
  font-size: 20px;
  margin: 28px 0 8px;
}

p,
li {
  color: var(--muted);
}

.lead {
  font-size: 18px;
  max-width: 760px;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 12px 18px;
  border-radius: 8px;
  font-weight: 800;
  text-decoration: none;
}

.button.primary {
  background: var(--cta);
  color: #fff;
}

.button.secondary {
  border: 1px solid var(--line);
  color: var(--text);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.card,
.note,
.toc {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 20px;
}

.card h2,
.card h3 {
  margin-top: 0;
}

.card a {
  color: var(--accent);
  font-weight: 800;
  text-decoration: none;
}

.metric {
  color: var(--accent);
  font-size: 28px;
  font-weight: 900;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  overflow-x: auto;
}

th,
td {
  border: 1px solid var(--line);
  padding: 12px;
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--bg-soft);
  color: var(--text);
}

.article-meta {
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
}

@media (max-width: 640px) {
  .site-header,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero-inner,
  .content,
  .cards {
    padding: 36px 20px;
  }

  .button {
    width: 100%;
  }
}