/* ====================================================================
   RT-Lab ブログ共通スタイル
   /blog/（一覧）と /blog/<slug>/（記事）で読み込む。
   ツールページのセレクタは上書きしない（.blog- プレフィックスで隔離）。
   ==================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --main: #1a5f9e;
  --main-light: #2980b9;
  --bg: #f5f7fb;
  --text: #243447;
  --muted: #5b6b7d;
  --white: #ffffff;
  --line: #dbe4ee;
}

body {
  font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.85;
}

/* ---- ヘッダー / フッター（aboutページと同じ流儀） ---- */
.blog-header {
  background: linear-gradient(135deg, var(--main) 0%, var(--main-light) 100%);
  color: var(--white);
  padding: 1.25rem 1.5rem;
}

.blog-header-inner,
.blog-main,
.blog-footer {
  max-width: 820px;
  margin: 0 auto;
}

.blog-brand {
  color: var(--white);
  text-decoration: none;
  font-size: 1.2rem;
  font-weight: 700;
}

.blog-subnav {
  margin-top: 0.75rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.blog-subnav a {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  font-size: 0.92rem;
}

.blog-footer {
  padding: 0 1.5rem 2rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.blog-footer-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.blog-footer a { color: var(--main); }

.blog-main {
  padding: 2rem 1.5rem 3rem;
}

/* ---- 一覧ページ ---- */
.blog-hero {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: 0 6px 24px rgba(26, 95, 158, 0.08);
  padding: 2rem;
  margin-bottom: 1.5rem;
}

.blog-hero h1 {
  font-size: 1.7rem;
  margin-bottom: 0.6rem;
}

.blog-hero p { color: var(--muted); }

.blog-list {
  display: grid;
  gap: 1rem;
}

.blog-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1.4rem 1.5rem;
  transition: box-shadow 0.2s, transform 0.2s;
}

.blog-card:hover {
  box-shadow: 0 8px 28px rgba(26, 95, 158, 0.14);
  transform: translateY(-2px);
}

.blog-card-meta {
  font-size: 0.82rem;
  color: var(--muted);
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 0.4rem;
}

.blog-card-tag {
  background: #eef2ff;
  color: var(--main);
  border-radius: 999px;
  padding: 0.1rem 0.7rem;
  font-weight: 600;
}

.blog-card h2 {
  font-size: 1.15rem;
  line-height: 1.5;
  margin-bottom: 0.45rem;
}

.blog-card h2 a {
  color: var(--text);
  text-decoration: none;
}

.blog-card h2 a:hover { color: var(--main); }

.blog-card p {
  color: var(--muted);
  font-size: 0.93rem;
}

.blog-card-more {
  display: inline-block;
  margin-top: 0.5rem;
  color: var(--main);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
}

/* ---- 記事ページ ---- */
.blog-article {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: 0 6px 24px rgba(26, 95, 158, 0.08);
  padding: 2.2rem 2rem 2.4rem;
}

.blog-article-meta {
  font-size: 0.85rem;
  color: var(--muted);
  display: flex;
  gap: 0.9rem;
  flex-wrap: wrap;
  margin-bottom: 0.8rem;
}

.blog-article h1 {
  font-size: 1.65rem;
  line-height: 1.5;
  margin-bottom: 1.1rem;
}

.blog-article .blog-lead {
  color: var(--muted);
  margin-bottom: 1.6rem;
}

.blog-article h2 {
  font-size: 1.28rem;
  line-height: 1.5;
  margin: 2.4rem 0 0.9rem;
  padding-left: 0.7rem;
  border-left: 4px solid var(--main);
}

.blog-article h3 {
  font-size: 1.08rem;
  margin: 1.7rem 0 0.6rem;
}

.blog-article p { margin-bottom: 1rem; }

.blog-article ul,
.blog-article ol {
  margin: 0 0 1rem;
  padding-left: 1.5rem;
}

.blog-article li { margin-bottom: 0.35rem; }

.blog-article strong { color: var(--main); }

.blog-formula {
  display: block;
  background: #eef2ff;
  border-radius: 8px;
  padding: 0.8rem 1.1rem;
  margin: 0.8rem 0 1rem;
  font-weight: 700;
  overflow-x: auto;
}

.blog-note {
  background: #fff8e6;
  border: 1px solid #f0dfa8;
  border-radius: 8px;
  padding: 0.8rem 1.1rem;
  margin: 1rem 0;
  font-size: 0.92rem;
}

.blog-table-wrap {
  overflow-x: auto;
  margin: 1rem 0 1.2rem;
}

.blog-article table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.92rem;
}

.blog-article th,
.blog-article td {
  border: 1px solid var(--line);
  padding: 0.55rem 0.8rem;
  text-align: left;
  vertical-align: top;
}

.blog-article th {
  background: #eef4fa;
  white-space: nowrap;
}

/* 目次 */
.blog-toc {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem 1.3rem;
  margin-bottom: 1.8rem;
  font-size: 0.93rem;
}

.blog-toc-title {
  font-weight: 700;
  margin-bottom: 0.4rem;
}

.blog-toc ol {
  margin: 0;
  padding-left: 1.3rem;
}

.blog-toc a {
  color: var(--main);
  text-decoration: none;
}

.blog-toc a:hover { text-decoration: underline; }

/* 関連ツールCTA */
.blog-cta {
  display: block;
  background: linear-gradient(135deg, #eef4fa 0%, #e7f0f9 100%);
  border: 1px solid var(--line);
  border-left: 4px solid var(--main);
  border-radius: 10px;
  padding: 1.1rem 1.3rem;
  margin: 1.6rem 0;
  text-decoration: none;
  color: var(--text);
  transition: box-shadow 0.2s;
}

.blog-cta:hover { box-shadow: 0 6px 20px rgba(26, 95, 158, 0.16); }

.blog-cta-label {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--main);
  letter-spacing: 0.05em;
}

.blog-cta-title {
  font-weight: 700;
  font-size: 1.02rem;
  margin: 0.15rem 0;
}

.blog-cta-desc {
  font-size: 0.88rem;
  color: var(--muted);
}

/* 著者ボックス */
.blog-author {
  display: flex;
  gap: 0.9rem;
  align-items: flex-start;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 1.1rem 1.3rem;
  margin-top: 2.2rem;
  font-size: 0.92rem;
}

.blog-author-icon {
  font-size: 1.8rem;
  line-height: 1;
}

.blog-author-name {
  font-weight: 700;
  margin-bottom: 0.2rem;
}

.blog-author p { margin: 0; color: var(--muted); }

.blog-author a { color: var(--main); }

/* 免責・出典 */
.blog-disclaimer {
  background: #fdf2f2;
  border: 1px solid #f0c9c9;
  border-radius: 8px;
  padding: 0.9rem 1.2rem;
  margin-top: 1.6rem;
  font-size: 0.88rem;
  color: #7a3b3b;
}

.blog-refs {
  margin-top: 1.6rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
  font-size: 0.85rem;
  color: var(--muted);
}

.blog-refs-title {
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: var(--text);
}

.blog-refs ol {
  padding-left: 1.3rem;
  margin: 0;
}

.blog-refs a {
  color: var(--main);
  word-break: break-all;
}

@media (max-width: 640px) {
  .blog-article { padding: 1.6rem 1.2rem 1.8rem; }
  .blog-article h1 { font-size: 1.35rem; }
  .blog-hero h1 { font-size: 1.4rem; }
}