:root {
  --brand-teal: #396B76;
  --brand-cyan: #0891b2;
  --brand-cyan-dark: #0d1f3c;
  --brand-light: #48cae4;
  --bg: #f6f9fb;
  --bg-card: #ffffff;
  --text: #1a2433;
  --text-muted: #5a6a78;
  --border: #e3eaef;
  --cat-usecase: #0891b2;
  --cat-knowhow: #14b8a6;
  --cat-trend: #d97706;
  --cat-news: #7c3aed;
  --cat-glossary: #16a34a;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Header --- */
.site-header {
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 40px; height: 40px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--brand-teal), var(--brand-cyan-dark));
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
  letter-spacing: 0.05em;
  font-size: 14px;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name { font-weight: 700; font-size: 15px; }
.brand-tag {
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.06em;
}
.site-nav a {
  font-size: 14px;
  color: var(--text-muted);
}

/* --- Hero --- */
.hero {
  background: linear-gradient(135deg, var(--brand-teal), var(--brand-cyan-dark));
  color: #fff;
  padding: 64px 0 56px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: -80px; right: -80px;
  width: 320px; height: 320px;
  border-radius: 50%;
  background: rgba(72, 202, 228, 0.15);
}
.hero::after {
  content: "";
  position: absolute;
  bottom: -100px; left: -60px;
  width: 280px; height: 280px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.04);
}
.hero .container { position: relative; z-index: 1; }
.hero-eyebrow {
  letter-spacing: 0.18em;
  font-size: 13px;
  color: var(--brand-light);
  margin: 0 0 12px;
  font-weight: 600;
}
.hero-title {
  font-size: 36px;
  margin: 0 0 20px;
  line-height: 1.35;
  font-weight: 700;
}
.hero-lead {
  font-size: 16px;
  margin: 0 0 24px;
  max-width: 740px;
  color: #d8e8eb;
}
.hero-meta { display: flex; gap: 12px; flex-wrap: wrap; }
.badge {
  background: rgba(255, 255, 255, 0.1);
  color: #d8e8eb;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
}

/* --- Main --- */
.main { padding: 56px 24px 72px; }

.section-title {
  font-size: 22px;
  margin: 0 0 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}

/* --- Categories nav --- */
.categories { margin-bottom: 56px; }
.cat-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 12px;
  list-style: none;
  padding: 0;
  margin: 0;
}
.cat-list li {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.cat-list li span { font-size: 12px; color: var(--text-muted); }
.cat {
  font-weight: 700;
  color: var(--text);
}
.cat-list .cat::before {
  content: "";
  display: inline-block;
  width: 8px; height: 8px;
  border-radius: 50%;
  margin-right: 8px;
  vertical-align: middle;
}
.cat-list .cat-usecase::before  { background: var(--cat-usecase); }
.cat-list .cat-knowhow::before  { background: var(--cat-knowhow); }
.cat-list .cat-trend::before    { background: var(--cat-trend); }
.cat-list .cat-news::before     { background: var(--cat-news); }
.cat-list .cat-glossary::before { background: var(--cat-glossary); }

/* --- Article sections --- */
.article-section { margin-bottom: 56px; }
.cat-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 4px 10px;
  border-radius: 999px;
  color: #fff;
}
.cat-tag.cat-usecase  { background: var(--cat-usecase); }
.cat-tag.cat-knowhow  { background: var(--cat-knowhow); }
.cat-tag.cat-trend    { background: var(--cat-trend); }
.cat-tag.cat-news     { background: var(--cat-news); }
.cat-tag.cat-glossary { background: var(--cat-glossary); }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(310px, 1fr));
  gap: 24px;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(13, 31, 60, 0.08);
}
.card-thumb {
  display: block;
  aspect-ratio: 1200 / 630;
  overflow: hidden;
  background: #0d1f3c;
}
.card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.card-body { padding: 18px 20px 22px; }
.card-meta {
  font-size: 12px;
  color: var(--text-muted);
  margin: 0 0 8px;
}
.card-title {
  font-size: 16px;
  line-height: 1.5;
  margin: 0 0 10px;
  font-weight: 700;
}
.card-title a { color: var(--text); }
.card-title a:hover { color: var(--brand-cyan); text-decoration: none; }
.card-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  margin: 0 0 12px;
  line-height: 1.65;
}
.card-tags {
  font-size: 12px;
  color: var(--brand-cyan);
  margin: 0;
  letter-spacing: 0.02em;
}

/* --- CTA --- */
.cta-section {
  margin-top: 72px;
  padding: 40px 32px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--brand-teal), var(--brand-cyan-dark));
  color: #fff;
  text-align: center;
}
.cta-section h2 {
  margin: 0 0 14px;
  font-size: 22px;
}
.cta-section p {
  margin: 0 auto 16px;
  max-width: 640px;
  color: #d8e8eb;
  font-size: 14.5px;
}
.cta-btn {
  display: inline-block;
  margin-top: 8px;
  padding: 12px 28px;
  background: var(--brand-light);
  color: #0d1f3c;
  border-radius: 999px;
  font-weight: 700;
  font-size: 15px;
}
.cta-btn:hover { text-decoration: none; opacity: 0.92; }

/* --- Pagination --- */
.pagination {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin: 32px 0 16px;
  flex-wrap: wrap;
}
.pagination .page {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  height: 36px;
  padding: 0 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #ffffff;
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
}
.pagination .page:hover { text-decoration: none; border-color: var(--brand-cyan); color: var(--brand-cyan); }
.pagination .page.current {
  background: var(--brand-cyan-dark);
  color: #ffffff;
  border-color: var(--brand-cyan-dark);
  cursor: default;
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--border);
  background: #ffffff;
  padding: 32px 0 40px;
  color: var(--text-muted);
}
.site-footer p { margin: 0 0 6px; font-size: 13px; }
.site-footer .small { font-size: 12px; }

/* --- Responsive --- */
@media (max-width: 640px) {
  .hero { padding: 48px 0 40px; }
  .hero-title { font-size: 28px; }
  .hero-lead { font-size: 15px; }
  .main { padding: 40px 16px 48px; }
  .container { padding: 0 16px; }
  .header-inner { padding: 12px 16px; }
  .brand-name { font-size: 14px; }
  .cta-section { padding: 32px 20px; }
}