/*
Theme Name: AI Manabi
Theme URI: https://example.com/ai-manabi
Author: AI Manabi
Author URI: https://example.com
Description: AI学習の初心者向け学習サイト用WordPressテーマ。検索流入を最優先にしたSEO最適化（構造化データ、OGP、パンくず、自動メタディスクリプション）を内蔵。プラグイン不要で基本的なSEO対策が完結します。
Version: 1.0.0
Requires at least: 6.0
Tested up to: 6.5
Requires PHP: 7.4
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Text Domain: ai-manabi
Tags: blog, education, seo, two-columns, custom-menu, featured-images, threaded-comments
*/

/* =========================================================
   デザイントークン
   ========================================================= */
:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-accent: #0ea5e9;
  --color-text: #1f2937;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-bg: #ffffff;
  --color-bg-soft: #f8fafc;
  --color-bg-card: #ffffff;
  --color-success: #10b981;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 30px rgba(2,12,27,.08);
  --maxw: 1140px;
  --font: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Noto Sans JP", Meiryo, sans-serif;
}

/* =========================================================
   ベース
   ========================================================= */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.85;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; }
a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* スキップリンク（アクセシビリティ） */
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 999;
  background: var(--color-primary); color: #fff; padding: 10px 16px;
}
.skip-link:focus { left: 8px; top: 8px; }

/* =========================================================
   ヘッダー
   ========================================================= */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--color-border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; height: 66px;
}
.site-branding { display: flex; align-items: center; gap: 10px; }
.site-logo-mark {
  width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: grid; place-items: center; color: #fff; font-weight: 800; font-size: 16px;
}
.site-title { font-size: 1.2rem; font-weight: 800; margin: 0; letter-spacing: .2px; }
.site-title a { color: var(--color-text); }
.site-description { font-size: .72rem; color: var(--color-muted); margin: 0; }

.main-nav ul { list-style: none; display: flex; gap: 4px; margin: 0; padding: 0; }
.main-nav a {
  display: block; padding: 8px 14px; border-radius: 8px;
  color: var(--color-text); font-weight: 600; font-size: .95rem;
}
.main-nav a:hover { background: var(--color-bg-soft); text-decoration: none; }
.menu-toggle { display: none; background: none; border: 1px solid var(--color-border);
  border-radius: 8px; padding: 8px 10px; cursor: pointer; font-size: 1.1rem; }

/* =========================================================
   レイアウト
   ========================================================= */
.site-main { padding: 36px 0 60px; }
.content-area {
  display: grid; grid-template-columns: minmax(0,1fr) 320px; gap: 40px;
  max-width: var(--maxw); margin: 0 auto; padding: 0 20px;
}
@media (max-width: 900px) {
  .content-area { grid-template-columns: 1fr; }
}

/* =========================================================
   パンくず
   ========================================================= */
.breadcrumb { font-size: .82rem; color: var(--color-muted); margin: 0 0 18px; }
.breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; margin: 0; padding: 0; }
.breadcrumb li::after { content: "›"; margin-left: 6px; color: #cbd5e1; }
.breadcrumb li:last-child::after { content: ""; }

/* =========================================================
   ヒーロー（トップ）
   ========================================================= */
.hero {
  background: linear-gradient(160deg, #eff6ff 0%, #f0f9ff 60%, #ffffff 100%);
  border-bottom: 1px solid var(--color-border);
  padding: 64px 0 56px;
}
.hero-inner { max-width: 820px; }
.hero .eyebrow {
  display: inline-block; font-size: .78rem; font-weight: 700; color: var(--color-primary);
  background: #dbeafe; padding: 5px 12px; border-radius: 999px; margin-bottom: 16px;
}
.hero h1 { font-size: clamp(1.8rem, 4vw, 2.7rem); line-height: 1.3; margin: 0 0 16px; letter-spacing: .3px; }
.hero p { font-size: 1.08rem; color: #374151; margin: 0 0 28px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-block; padding: 13px 24px; border-radius: 10px; font-weight: 700;
  background: var(--color-primary); color: #fff; transition: transform .08s ease, background .15s;
}
.btn:hover { background: var(--color-primary-dark); text-decoration: none; transform: translateY(-1px); }
.btn-ghost { background: #fff; color: var(--color-primary); border: 1px solid var(--color-border); }
.btn-ghost:hover { background: var(--color-bg-soft); }

/* セクション見出し */
.section { padding: 56px 0; }
.section-soft { background: var(--color-bg-soft); }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 36px; }
.section-head h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin: 0 0 10px; }
.section-head p { color: var(--color-muted); margin: 0; }

/* 学習ステップ */
.steps { display: grid; grid-template-columns: repeat(4,1fr); gap: 18px; }
@media (max-width: 820px){ .steps{ grid-template-columns: repeat(2,1fr);} }
@media (max-width: 480px){ .steps{ grid-template-columns: 1fr;} }
.step-card {
  background: var(--color-bg-card); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 24px 20px; box-shadow: var(--shadow);
}
.step-num {
  width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center;
  background: #dbeafe; color: var(--color-primary); font-weight: 800; margin-bottom: 12px;
}
.step-card h3 { margin: 0 0 8px; font-size: 1.08rem; }
.step-card p { margin: 0; font-size: .92rem; color: var(--color-muted); }

/* カテゴリーカード */
.cat-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 20px; }
@media (max-width: 820px){ .cat-grid{ grid-template-columns: 1fr;} }
.cat-card {
  display: block; background: #fff; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 26px 22px; box-shadow: var(--shadow);
  transition: transform .12s ease, box-shadow .12s ease;
}
.cat-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); text-decoration: none; }
.cat-card .cat-icon { font-size: 1.7rem; margin-bottom: 10px; }
.cat-card h3 { margin: 0 0 6px; color: var(--color-text); font-size: 1.15rem; }
.cat-card p { margin: 0; color: var(--color-muted); font-size: .9rem; }

/* =========================================================
   記事カード（一覧）
   ========================================================= */
.posts-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 24px; }
@media (max-width: 620px){ .posts-grid{ grid-template-columns: 1fr;} }
.post-card {
  background: #fff; border: 1px solid var(--color-border); border-radius: var(--radius);
  overflow: hidden; box-shadow: var(--shadow); display: flex; flex-direction: column;
  transition: transform .12s ease, box-shadow .12s ease;
}
.post-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.post-card .thumb { aspect-ratio: 16/9; background: linear-gradient(135deg,#dbeafe,#e0f2fe); display:block; }
.post-card .thumb img { width: 100%; height: 100%; object-fit: cover; }
.post-card .body { padding: 18px 18px 20px; display: flex; flex-direction: column; gap: 10px; flex: 1; }
.post-card .cat-label { font-size: .72rem; font-weight: 700; color: var(--color-primary); }
.post-card h2, .post-card h3 { margin: 0; font-size: 1.1rem; line-height: 1.5; }
.post-card h2 a, .post-card h3 a { color: var(--color-text); }
.post-card .excerpt { color: var(--color-muted); font-size: .88rem; margin: 0; }
.post-card .meta { margin-top: auto; font-size: .76rem; color: var(--color-muted); }

/* =========================================================
   単一記事
   ========================================================= */
.single-article { background: #fff; }
.article-header { margin-bottom: 28px; }
.article-header .cat-label { font-size: .8rem; font-weight: 700; color: var(--color-primary); }
.article-title { font-size: clamp(1.6rem, 3.4vw, 2.3rem); line-height: 1.35; margin: 10px 0 14px; }
.article-meta { font-size: .82rem; color: var(--color-muted); display: flex; gap: 14px; flex-wrap: wrap; }
.article-featured { margin: 0 0 28px; border-radius: var(--radius); overflow: hidden; }

.entry-content { font-size: 1.04rem; }
.entry-content h2 {
  font-size: 1.5rem; margin: 2.2em 0 .8em; padding: 12px 0 12px 16px;
  border-left: 5px solid var(--color-primary); background: var(--color-bg-soft); border-radius: 0 8px 8px 0;
}
.entry-content h3 { font-size: 1.25rem; margin: 1.8em 0 .6em; padding-bottom: 6px; border-bottom: 2px solid var(--color-border); }
.entry-content p { margin: 1em 0; }
.entry-content ul, .entry-content ol { padding-left: 1.4em; margin: 1em 0; }
.entry-content li { margin: .4em 0; }
.entry-content a { text-decoration: underline; }
.entry-content blockquote {
  margin: 1.4em 0; padding: 12px 20px; border-left: 4px solid var(--color-accent);
  background: var(--color-bg-soft); color: #374151; border-radius: 0 8px 8px 0;
}
.entry-content code {
  background: #f1f5f9; padding: .15em .4em; border-radius: 5px; font-size: .9em;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
.entry-content pre {
  background: #0f172a; color: #e2e8f0; padding: 18px; border-radius: var(--radius-sm);
  overflow-x: auto; font-size: .9rem;
}
.entry-content pre code { background: none; padding: 0; color: inherit; }
.entry-content img { border-radius: var(--radius-sm); }
.entry-content table { width: 100%; border-collapse: collapse; margin: 1.4em 0; font-size: .95rem; }
.entry-content th, .entry-content td { border: 1px solid var(--color-border); padding: 10px 12px; text-align: left; }
.entry-content th { background: var(--color-bg-soft); }

/* 目次 */
.toc {
  background: var(--color-bg-soft); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 18px 22px; margin: 0 0 28px;
}
.toc-title { font-weight: 800; margin: 0 0 10px; font-size: 1rem; }
.toc ol { margin: 0; padding-left: 1.2em; }
.toc a { color: var(--color-text); }

/* CTAボックス（記事内・アフィリエイト等にも流用可） */
.cta-box {
  background: linear-gradient(135deg, #eff6ff, #f0f9ff); border: 1px solid #bfdbfe;
  border-radius: var(--radius); padding: 24px; margin: 2em 0; text-align: center;
}
.cta-box h3 { margin: 0 0 8px; }
.cta-box p { margin: 0 0 16px; color: #374151; }

/* タグ・著者 */
.entry-tags { margin: 28px 0; display: flex; flex-wrap: wrap; gap: 8px; }
.entry-tags a {
  font-size: .8rem; background: var(--color-bg-soft); border: 1px solid var(--color-border);
  padding: 5px 12px; border-radius: 999px; color: var(--color-muted);
}
.entry-tags a:hover { text-decoration: none; border-color: var(--color-primary); color: var(--color-primary); }

.post-nav { display: flex; justify-content: space-between; gap: 16px; margin: 32px 0; }
.post-nav a { flex: 1; padding: 16px; border: 1px solid var(--color-border); border-radius: var(--radius); }
.post-nav .nav-next { text-align: right; }
.post-nav small { display: block; color: var(--color-muted); font-size: .72rem; }

/* =========================================================
   サイドバー
   ========================================================= */
.sidebar .widget {
  background: #fff; border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 22px; margin-bottom: 24px; box-shadow: var(--shadow);
}
.widget-title { font-size: 1.05rem; margin: 0 0 14px; padding-bottom: 10px; border-bottom: 2px solid var(--color-primary); }
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li { padding: 7px 0; border-bottom: 1px dashed var(--color-border); font-size: .92rem; }
.sidebar li:last-child { border-bottom: none; }
.sidebar a { color: var(--color-text); }
.search-form { display: flex; gap: 8px; }
.search-form input[type=search] {
  flex: 1; padding: 10px 12px; border: 1px solid var(--color-border); border-radius: 8px; font-size: .9rem;
}
.search-form button { padding: 10px 16px; background: var(--color-primary); color: #fff; border: none; border-radius: 8px; cursor: pointer; }

/* =========================================================
   ページネーション
   ========================================================= */
.pagination { display: flex; justify-content: center; gap: 8px; margin: 40px 0 0; flex-wrap: wrap; }
.pagination .page-numbers {
  padding: 10px 16px; border: 1px solid var(--color-border); border-radius: 8px; color: var(--color-text);
}
.pagination .current { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }
.pagination a:hover { background: var(--color-bg-soft); text-decoration: none; }

/* =========================================================
   フッター
   ========================================================= */
.site-footer { background: #0f172a; color: #cbd5e1; padding: 50px 0 24px; margin-top: 40px; }
.footer-cols { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; margin-bottom: 32px; }
@media (max-width: 720px){ .footer-cols{ grid-template-columns: 1fr;} }
.site-footer h4 { color: #fff; font-size: 1rem; margin: 0 0 14px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { padding: 5px 0; font-size: .9rem; }
.site-footer a { color: #cbd5e1; }
.site-footer a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid #1e293b; padding-top: 20px; text-align: center; font-size: .82rem; color: #94a3b8; }

/* ページタイトル（アーカイブ等） */
.page-header { padding: 40px 0 24px; }
.page-header h1 { font-size: clamp(1.6rem, 3.4vw, 2.2rem); margin: 0 0 8px; }
.page-header p { color: var(--color-muted); margin: 0; }

/* レスポンシブナビ */
@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .main-nav { position: absolute; top: 66px; left: 0; right: 0; background: #fff;
    border-bottom: 1px solid var(--color-border); display: none; }
  .main-nav.is-open { display: block; }
  .main-nav ul { flex-direction: column; padding: 8px; }
  .main-nav a { padding: 12px 14px; }
}

/* ユーティリティ */
.text-center { text-align: center; }
.mt-32 { margin-top: 32px; }
.screen-reader-text { position: absolute; clip: rect(1px,1px,1px,1px); width: 1px; height: 1px; overflow: hidden; }