/* ============================================================
   記事ページ共通CSS（まなびAI ブログ）
   LPの浮世絵ポップテーマと整合
============================================================ */

:root {
  --color-ai: #1a3a5c;
  --color-shu: #d4442a;
  --color-kin: #a39463;
  --color-white: #ffffff;
  --color-bg: #faf8f5;
  --color-bg-dark: #f0ece4;
  --color-text: #1a1a1a;
  --color-text-light: #5a5a5a;
  --color-border: #d4c8b0;
  --font-ja: 'Noto Sans JP', 'Hiragino Sans', 'Yu Gothic', sans-serif;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --shadow-card: 0 4px 24px rgba(26,58,92,0.08);
  --shadow-hover: 0 8px 32px rgba(26,58,92,0.14);
  --container-max: 880px;
  --container-pad: clamp(20px, 5vw, 40px);
  --muted: #6c757d;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-ja);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.85;
  font-size: 16px;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: var(--color-ai); }

/* ============================================================
   ナビゲーション（LPと共通）
============================================================ */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 248, 245, 0.94);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}
.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 var(--container-pad);
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.nav-logo-mark {
  width: 36px; height: 36px;
  background: var(--color-shu);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 900;
  color: white;
  letter-spacing: 0.05em;
  transform: rotate(-2deg);
}
.nav-logo-text {
  font-size: 18px;
  font-weight: 900;
  color: var(--color-ai);
  letter-spacing: 0.05em;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}
.nav-links a {
  color: var(--color-text-light);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--color-ai); }
.nav-links a.active { color: var(--color-ai); font-weight: 700; }
.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--color-shu);
  color: white !important;
  font-size: 13px;
  font-weight: 700 !important;
  padding: 9px 20px;
  border-radius: var(--radius-sm);
  transition: background 0.2s, transform 0.15s;
}
.nav-cta:hover { background: #b83520; transform: translateY(-1px); }

@media (max-width: 720px) {
  .nav-links { gap: 14px; }
  .nav-links a:not(.nav-cta) { font-size: 13px; }
  .nav-cta { padding: 7px 14px; font-size: 12px; }
}

/* ============================================================
   ページコンテナ
============================================================ */
.page {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 32px var(--container-pad) 80px;
}

/* パンくず */
.breadcrumb {
  font-size: 13px;
  color: var(--color-text-light);
  margin-bottom: 16px;
}
.breadcrumb a { color: var(--color-text-light); text-decoration: none; }
.breadcrumb a:hover { color: var(--color-ai); }
.breadcrumb span { color: var(--color-text); }

/* ============================================================
   記事ヘッダー
============================================================ */
.article-header {
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 2px solid var(--color-bg-dark);
}
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-bottom: 14px;
  font-size: 13px;
}
.article-tag {
  display: inline-block;
  padding: 4px 10px;
  background: var(--color-ai);
  color: white;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
}
.article-tag.tag-elementary { background: #e0782b; }
.article-tag.tag-junior_high { background: var(--color-ai); }
.article-tag.tag-high_school { background: #5a3a8e; }
.article-tag.tag-guide { background: var(--color-kin); }
.article-tag-subject {
  display: inline-block;
  padding: 4px 10px;
  background: var(--color-bg-dark);
  color: var(--color-text);
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
}
.article-tag-format {
  display: inline-block;
  padding: 4px 10px;
  background: #fef9ec;
  color: #6b5c2e;
  border: 1px solid var(--color-kin);
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.article-date {
  color: var(--color-text-light);
  font-size: 13px;
}
.article-title {
  font-size: clamp(22px, 4vw, 30px);
  font-weight: 900;
  line-height: 1.4;
  color: var(--color-ai);
  margin-bottom: 12px;
}
.article-lead {
  font-size: 16px;
  color: var(--color-text-light);
  line-height: 1.8;
}
.article-eyecatch {
  margin: 0 0 28px;
}
.article-eyecatch img {
  width: 100%;
  height: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  background: white;
}

/* ============================================================
   記事本文
============================================================ */
.article-body {
  font-size: 16px;
  line-height: 1.9;
}
.article-body h2 {
  font-size: 22px;
  font-weight: 900;
  color: var(--color-ai);
  margin: 40px 0 16px;
  padding-left: 14px;
  border-left: 5px solid var(--color-shu);
}
.article-body h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ai);
  margin: 28px 0 12px;
}
.article-body p { margin: 12px 0; }
.article-body ul, .article-body ol { margin: 12px 0 12px 28px; }
.article-body li { margin: 6px 0; }
.article-body strong { color: var(--color-ai); }
.article-body a {
  color: var(--color-shu);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* 制作プロセスの注記 */
.article-note {
  background: #fef9ec;
  border-left: 4px solid var(--color-kin);
  padding: 16px 20px;
  margin: 24px 0;
  font-size: 14px;
  color: #6b5c2e;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  line-height: 1.7;
}
.article-note strong { color: #5a4a1a; }

/* つまずきポイントブロック */
.tsumazuki-box {
  background: white;
  border: 2px solid var(--color-bg-dark);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 24px 0;
}
.tsumazuki-box h3 {
  margin-top: 0;
  display: flex;
  align-items: center;
  gap: 8px;
}
.tsumazuki-box h3::before {
  content: "?";
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px; height: 28px;
  background: var(--color-shu);
  color: white;
  border-radius: 50%;
  font-weight: 900;
  font-size: 16px;
}

/* 教材本体ブロック */
.material-frame {
  background: white;
  border: 2px solid var(--color-ai);
  border-radius: var(--radius-md);
  padding: 28px 28px 24px;
  margin: 24px 0;
  box-shadow: var(--shadow-card);
  position: relative;
}
.material-frame::before {
  content: "AI生成教材";
  position: absolute;
  top: -12px;
  left: 20px;
  background: var(--color-ai);
  color: white;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
}
.material-frame h1,
.material-frame h2,
.material-frame h3 {
  color: var(--color-ai);
}
.material-frame h1 { font-size: 20px; margin: 0 0 12px; padding: 0; border: none; }
.material-frame h2 { font-size: 17px; margin: 18px 0 10px; padding: 0; border: none; }
.material-frame h3 { font-size: 15px; margin: 14px 0 8px; }
.material-frame p { margin: 8px 0; }
.material-frame .katex { font-size: 1.05em; }

/* 表（記事本文内のテーブル） */
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 15px;
  line-height: 1.7;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.article-body thead th {
  background: var(--color-ai);
  color: #fff;
  font-weight: 700;
  text-align: left;
  vertical-align: top;
  padding: 12px 14px;
}
.article-body tbody th,
.article-body tbody td {
  padding: 12px 14px;
  vertical-align: top;
  border-top: 1px solid var(--color-border);
}
.article-body tbody th {
  text-align: left;
  font-weight: 700;
  background: var(--color-bg);
  white-space: nowrap;
}
.article-body tbody tr:nth-child(even) td {
  background: #fbfaf7;
}
.article-body table + p { margin-top: 16px; }

/* 狭い画面では横スクロール可能に */
@media (max-width: 720px) {
  .article-body table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }
}

/* コードブロック・アスキー図（等幅・横スクロール・整形保持） */
.article-body pre {
  background: #1e2230;
  color: #e6e9f0;
  border-radius: 8px;
  padding: 14px 16px;
  margin: 14px 0;
  overflow-x: auto;
  line-height: 1.5;
}
.article-body pre code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 13px;
  white-space: pre;
  background: none;
  padding: 0;
}

.material-meta {
  font-size: 12px;
  color: var(--color-text-light);
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.material-meta span { display: inline-flex; align-items: center; gap: 4px; }

/* 編集・参照情報 */
.editorial-info {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 28px 0;
}
.editorial-info h2 {
  font-size: 18px;
  margin: 0 0 12px;
  padding-left: 10px;
  border-left-width: 4px;
}
.editorial-info ul {
  margin: 0 0 0 20px;
  color: var(--color-text-light);
  font-size: 14px;
  line-height: 1.8;
}

/* CTAブロック */
.article-cta {
  background: linear-gradient(135deg, var(--color-ai) 0%, #2a4d75 100%);
  color: white;
  padding: 28px 24px;
  border-radius: var(--radius-md);
  margin: 32px 0;
  text-align: center;
  box-shadow: var(--shadow-card);
}
.article-cta h3 {
  color: white;
  font-size: 20px;
  margin-bottom: 12px;
}
.article-cta p {
  color: rgba(255,255,255,0.9);
  font-size: 14px;
  margin-bottom: 18px;
  line-height: 1.7;
}
.cta-btn {
  display: inline-block;
  background: var(--color-shu);
  color: white !important;
  font-size: 15px;
  font-weight: 700;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
  letter-spacing: 0.05em;
}
.cta-btn:hover { background: #b83520; transform: translateY(-2px); }

/* FAQ */
.article-faq {
  margin: 32px 0;
}
.article-faq h2 {
  font-size: 22px;
  font-weight: 900;
  color: var(--color-ai);
  margin: 40px 0 16px;
  padding-left: 14px;
  border-left: 5px solid var(--color-shu);
}
.faq-item {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 18px 22px;
  margin: 12px 0;
}
.faq-item h3 {
  color: var(--color-ai);
  font-size: 16px;
  margin: 0 0 8px;
  display: flex;
  gap: 10px;
  align-items: baseline;
}
.faq-item h3::before {
  content: "Q.";
  color: var(--color-shu);
  font-weight: 900;
}
.faq-item p {
  margin: 0;
  padding-left: 24px;
  position: relative;
  color: var(--color-text);
}
.faq-item p::before {
  content: "A.";
  position: absolute;
  left: 0;
  color: var(--color-ai);
  font-weight: 900;
}

/* 関連記事 */
.related-articles {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 2px solid var(--color-bg-dark);
}
.related-articles h2 {
  font-size: 20px;
  font-weight: 900;
  color: var(--color-ai);
  margin-bottom: 16px;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}
.related-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px;
  text-decoration: none;
  color: inherit;
  display: block;
  transition: transform 0.2s, box-shadow 0.2s;
}
.related-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}
.related-card h3 {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-ai);
  margin: 6px 0;
  line-height: 1.5;
}
.related-card .tag {
  display: inline-block;
  padding: 2px 8px;
  background: var(--color-bg-dark);
  color: var(--color-text-light);
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 600;
}

/* 免責文 */
.article-disclaimer {
  margin-top: 32px;
  padding: 16px 20px;
  background: var(--color-bg-dark);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ============================================================
   記事一覧ページ
============================================================ */
.list-hero {
  text-align: center;
  padding: 40px var(--container-pad) 24px;
  max-width: var(--container-max);
  margin: 0 auto;
}
.list-hero h1 {
  font-size: clamp(26px, 5vw, 34px);
  font-weight: 900;
  color: var(--color-ai);
  margin-bottom: 12px;
}
.list-hero p {
  color: var(--color-text-light);
  font-size: 15px;
  line-height: 1.8;
}

.school-tabs {
  display: flex;
  gap: 8px;
  justify-content: center;
  flex-wrap: wrap;
  margin: 24px 0 32px;
  padding: 0 var(--container-pad);
}
.school-tab {
  padding: 10px 22px;
  background: white;
  border: 2px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
  color: var(--color-text-light);
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}
.school-tab:hover {
  border-color: var(--color-ai);
  color: var(--color-ai);
}
.school-tab.active {
  background: var(--color-ai);
  color: white;
  border-color: var(--color-ai);
}

.article-list {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad) 60px;
  display: grid;
  gap: 16px;
}
.list-card {
  display: block;
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 22px 26px;
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.list-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
  border-color: var(--color-ai);
}
.list-card[hidden] { display: none; }
.list-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-bottom: 10px;
}
.list-card h2 {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ai);
  margin: 8px 0;
  line-height: 1.5;
}
.list-card p {
  color: var(--color-text-light);
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 8px;
}
.list-empty {
  text-align: center;
  color: var(--color-text-light);
  padding: 60px 20px;
  font-size: 14px;
}
.list-empty[hidden] { display: none; }

/* ============================================================
   フッター（LPと共通の簡易版）
============================================================ */
.footer {
  background: var(--color-ai);
  color: rgba(255,255,255,0.85);
  padding: 32px var(--container-pad);
  text-align: center;
  font-size: 13px;
}
.footer a { color: white; text-decoration: none; margin: 0 12px; }
.footer a:hover { text-decoration: underline; }
.footer-copy {
  margin-top: 12px;
  opacity: 0.7;
  font-size: 12px;
}