/* ── ナビゲーション ─────────────────────────── */
.blog-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 16px 28px;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.92);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(8px);
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  font-weight: 800;
  font-size: 16px;
  margin-right: auto;
}

.blog-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
}

.blog-nav a:hover,
.blog-nav a[aria-current] {
  color: var(--accent);
}

/* ── メインレイアウト ───────────────────────── */
.blog-main {
  width: min(860px, 100%);
  margin: 0 auto;
  padding: 48px 28px 80px;
  background: #fff;
}

/* ── 記事一覧 ──────────────────────────────── */
.index-header {
  margin-bottom: 40px;
}

.index-header h1 {
  font-size: 36px;
  margin-bottom: 8px;
}

.index-header p {
  color: var(--muted);
  font-size: 15px;
}

.post-list {
  display: grid;
  gap: 16px;
}

.post-card {
  display: block;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.92);
  padding: 24px 28px;
  text-decoration: none;
  color: var(--ink);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.post-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(13, 124, 115, 0.1);
}

.post-card h2 {
  font-size: 20px;
  margin: 6px 0 8px;
  line-height: 1.35;
}

.post-date {
  color: var(--muted);
  font-size: 13px;
  margin: 0;
}

.post-desc {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
  margin: 0;
}

/* ── 記事ページ ────────────────────────────── */
.blog-article {
  max-width: 100%;
}

.article-header {
  margin-bottom: 40px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--line);
}

.article-header h1 {
  font-size: 36px;
  line-height: 1.25;
  margin: 8px 0 14px;
}

.article-date {
  color: var(--muted);
  font-size: 13px;
  margin: 0;
}

.article-desc {
  color: var(--muted);
  font-size: 16px;
  line-height: 1.7;
  margin: 0;
}

.article-body {
  font-size: 16px;
  line-height: 1.85;
}

.article-body img {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--line);
  margin: 8px 0;
}

.article-footer {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.back-link {
  color: var(--accent);
  text-decoration: none;
  font-weight: 700;
  font-size: 14px;
}

.back-link:hover {
  text-decoration: underline;
}

/* ── 関連記事 ──────────────────────────────── */
.related-articles {
  margin-top: 48px;
  padding: 24px 28px;
  background: #f8fafa;
  border-radius: 10px;
  border: 1px solid var(--line);
}

.related-articles h2 {
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 12px;
  color: var(--muted);
}

.related-articles ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.related-articles a {
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
}

.related-articles a:hover {
  text-decoration: underline;
}

/* ── レスポンシブ ──────────────────────────── */
@media (max-width: 600px) {
  .blog-nav {
    padding: 14px 16px;
    gap: 16px;
  }

  .blog-main {
    padding: 32px 16px 60px;
  }

  .article-header h1,
  .index-header h1 {
    font-size: 26px;
  }

  .post-card {
    padding: 18px 20px;
  }
}