/* =====================================================================
   Professional Data Engineer 学習教材 — 共通スタイル
   GCPブランドカラーを基調にした学習向けデザインシステム
   ===================================================================== */

:root {
  /* GCP Brand Colors */
  --g-blue: #4285F4;
  --g-red: #EA4335;
  --g-yellow: #FBBC04;
  --g-green: #34A853;
  --g-blue-dark: #1a73e8;
  --g-blue-deep: #174ea6;

  /* Semantic */
  --accent: var(--g-blue);
  --accent-hover: var(--g-blue-dark);

  /* Light theme surfaces */
  --bg: #f6f8fc;
  --bg-elev: #ffffff;
  --bg-soft: #eef3fb;
  --text: #1f2733;
  --text-soft: #5f6b80;
  --border: #e1e7f0;
  --shadow: 0 1px 3px rgba(60,64,67,.12), 0 2px 8px rgba(60,64,67,.06);
  --shadow-lg: 0 4px 20px rgba(60,64,67,.16);

  /* Level colors */
  --lv-basic: #34A853;      /* 📘 基礎 */
  --lv-practice: #4285F4;   /* 🔧 実践 */
  --lv-advanced: #EA4335;   /* 🎯 発展 */

  --radius: 14px;
  --radius-sm: 8px;
  --maxw: 1080px;
  --sidebar-w: 270px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
  --mono: "SF Mono", "Roboto Mono", Consolas, Menlo, monospace;
}

[data-theme="dark"] {
  --bg: #0f141c;
  --bg-elev: #181f2a;
  --bg-soft: #1f2733;
  --text: #e4e9f2;
  --text-soft: #9aa7bd;
  --border: #2a3340;
  --shadow: 0 1px 3px rgba(0,0,0,.4);
  --shadow-lg: 0 6px 24px rgba(0,0,0,.5);
  --accent: #8ab4f8;
  --accent-hover: #aecbfa;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  font-size: 16px;
}

/* ---------- Top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; gap: 16px;
  padding: 12px 24px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.topbar .brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 1.02rem; color: var(--text);
  text-decoration: none;
}
.topbar .brand .logo {
  width: 30px; height: 30px; border-radius: 8px;
  background: conic-gradient(from 90deg, var(--g-blue), var(--g-green), var(--g-yellow), var(--g-red), var(--g-blue));
  display: inline-block;
}
.topbar .spacer { flex: 1; }
.topbar nav a {
  color: var(--text-soft); text-decoration: none; margin: 0 10px;
  font-size: .92rem; font-weight: 600; padding: 6px 0; border-bottom: 2px solid transparent;
}
.topbar nav a:hover, .topbar nav a.active { color: var(--accent); border-bottom-color: var(--accent); }
.theme-toggle {
  cursor: pointer; border: 1px solid var(--border); background: var(--bg-soft);
  color: var(--text); border-radius: 20px; padding: 6px 12px; font-size: .85rem; font-weight: 600;
}

/* ---------- Layout ---------- */
.layout { display: flex; max-width: var(--maxw); margin: 0 auto; gap: 32px; padding: 0 24px; }
.content { flex: 1; min-width: 0; padding: 32px 0 80px; }
.page-wrap { max-width: var(--maxw); margin: 0 auto; padding: 32px 24px 80px; }

/* Sidebar (table of contents) */
.toc {
  position: sticky; top: 80px; align-self: flex-start;
  width: var(--sidebar-w); flex-shrink: 0;
  max-height: calc(100vh - 100px); overflow-y: auto;
  padding: 18px; margin-top: 32px;
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  font-size: .9rem;
}
.toc h4 { margin: 0 0 10px; font-size: .78rem; letter-spacing: .08em; text-transform: uppercase; color: var(--text-soft); }
.toc a { display: block; color: var(--text-soft); text-decoration: none; padding: 5px 10px; border-radius: 6px; border-left: 2px solid transparent; }
.toc a:hover { background: var(--bg-soft); color: var(--accent); }
.toc a.active { color: var(--accent); border-left-color: var(--accent); background: var(--bg-soft); font-weight: 600; }
.toc a.lv2 { padding-left: 22px; font-size: .85rem; }

/* ---------- Typography ---------- */
h1 { font-size: 2rem; line-height: 1.25; margin: 0 0 8px; letter-spacing: -.01em; }
h2 { font-size: 1.5rem; margin: 48px 0 16px; padding-bottom: 8px; border-bottom: 2px solid var(--border); scroll-margin-top: 80px; }
h3 { font-size: 1.18rem; margin: 32px 0 12px; scroll-margin-top: 80px; }
h4 { font-size: 1rem; margin: 20px 0 8px; }
p { margin: 12px 0; }
a { color: var(--accent); }
ul, ol { padding-left: 1.4em; }
li { margin: 6px 0; }
hr { border: none; border-top: 1px solid var(--border); margin: 32px 0; }
strong { color: var(--text); font-weight: 700; }
code:not(pre code) {
  font-family: var(--mono); font-size: .88em;
  background: var(--bg-soft); padding: 2px 6px; border-radius: 5px; color: var(--g-blue-deep);
}
[data-theme="dark"] code:not(pre code) { color: #aecbfa; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, var(--g-blue-deep), var(--g-blue) 60%, #5b9bf5);
  color: #fff; border-radius: var(--radius); padding: 40px 36px; box-shadow: var(--shadow-lg);
  position: relative; overflow: hidden;
}
.hero::after {
  content: ""; position: absolute; right: -60px; top: -60px; width: 240px; height: 240px;
  background: radial-gradient(circle, rgba(255,255,255,.18), transparent 70%); border-radius: 50%;
}
.hero h1 { color: #fff; font-size: 2.3rem; }
.hero p { color: rgba(255,255,255,.92); font-size: 1.05rem; max-width: 640px; }
.hero .badges { margin-top: 18px; display: flex; flex-wrap: wrap; gap: 10px; }
.hero .badges span {
  background: rgba(255,255,255,.18); border: 1px solid rgba(255,255,255,.3);
  padding: 6px 14px; border-radius: 20px; font-size: .85rem; font-weight: 600; backdrop-filter: blur(4px);
}

/* ---------- Cards ---------- */
.grid { display: grid; gap: 18px; }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-5 { grid-template-columns: repeat(5, 1fr); }

.card {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); transition: transform .15s, box-shadow .15s;
  text-decoration: none; color: inherit; display: block;
}
a.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); border-color: var(--accent); }
.card .num { font-size: .8rem; font-weight: 700; color: var(--accent); letter-spacing: .05em; }
.card h3 { margin: 6px 0 8px; font-size: 1.1rem; }
.card p { color: var(--text-soft); font-size: .92rem; margin: 0; }
.card .weight {
  display: inline-block; margin-top: 12px; font-size: .78rem; font-weight: 700;
  background: var(--bg-soft); color: var(--accent); padding: 3px 10px; border-radius: 12px;
}

/* ---------- Badges / level chips ---------- */
.chip { display: inline-block; font-size: .76rem; font-weight: 700; padding: 3px 10px; border-radius: 12px; }
.chip.basic { background: rgba(52,168,83,.14); color: var(--lv-basic); }
.chip.practice { background: rgba(66,133,244,.14); color: var(--lv-practice); }
.chip.advanced { background: rgba(234,67,53,.14); color: var(--lv-advanced); }
.chip.multi { background: rgba(251,188,4,.18); color: #b8860b; }

/* ---------- Callouts ---------- */
.callout { border-radius: var(--radius-sm); padding: 14px 18px; margin: 18px 0; border-left: 4px solid; background: var(--bg-soft); }
.callout.tip { border-color: var(--g-green); }
.callout.warn { border-color: var(--g-yellow); }
.callout.key { border-color: var(--g-blue); }
.callout.danger { border-color: var(--g-red); }
.callout .ttl { font-weight: 700; margin-bottom: 4px; display: block; }

/* ---------- Tables ---------- */
.table-wrap { overflow-x: auto; margin: 18px 0; border-radius: var(--radius-sm); border: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; font-size: .92rem; background: var(--bg-elev); }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--bg-soft); font-weight: 700; font-size: .85rem; position: sticky; top: 0; }
tr:last-child td { border-bottom: none; }
tbody tr:hover { background: var(--bg-soft); }

/* ---------- Code / diagram blocks ---------- */
pre {
  background: #0d1117; color: #c9d1d9; padding: 18px; border-radius: var(--radius-sm);
  overflow-x: auto; font-family: var(--mono); font-size: .86rem; line-height: 1.6; border: 1px solid #1f2733;
}
[data-theme="dark"] pre { background: #060a10; }
.diagram { background: var(--bg-soft); border: 1px dashed var(--border); border-radius: var(--radius-sm);
  padding: 18px; font-family: var(--mono); font-size: .85rem; white-space: pre; overflow-x: auto; color: var(--text); }

/* ---------- Accordion (details) ---------- */
details {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  margin: 12px 0; overflow: hidden;
}
details summary {
  cursor: pointer; padding: 14px 18px; font-weight: 600; list-style: none;
  display: flex; align-items: center; gap: 10px; user-select: none;
}
details summary::-webkit-details-marker { display: none; }
details summary::before { content: "▶"; color: var(--accent); font-size: .8rem; transition: transform .2s; }
details[open] summary::before { transform: rotate(90deg); }
details summary:hover { background: var(--bg-soft); }
details .detail-body { padding: 0 18px 16px; border-top: 1px solid var(--border); }

/* ---------- Progress ---------- */
.progress-wrap { background: var(--bg-soft); border-radius: 20px; height: 12px; overflow: hidden; margin: 8px 0; }
.progress-bar { height: 100%; background: linear-gradient(90deg, var(--g-blue), var(--g-green)); width: 0; transition: width .4s; }

/* ---------- Quiz ---------- */
.quiz-q { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; margin: 18px 0; box-shadow: var(--shadow); }
.quiz-q .q-head { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; flex-wrap: wrap; }
.quiz-q .q-num { font-weight: 800; color: var(--accent); }
.quiz-opt {
  display: block; padding: 12px 16px; margin: 8px 0; border: 1.5px solid var(--border);
  border-radius: var(--radius-sm); cursor: pointer; transition: .15s; background: var(--bg);
}
.quiz-opt:hover { border-color: var(--accent); background: var(--bg-soft); }
.quiz-opt.selected { border-color: var(--accent); background: rgba(66,133,244,.08); }
.quiz-opt.correct { border-color: var(--g-green); background: rgba(52,168,83,.12); }
.quiz-opt.wrong { border-color: var(--g-red); background: rgba(234,67,53,.1); }
.quiz-opt input { margin-right: 10px; }
.quiz-explain { margin-top: 14px; padding: 14px 18px; border-radius: var(--radius-sm);
  background: var(--bg-soft); border-left: 4px solid var(--g-blue); display: none; }
.quiz-explain.show { display: block; }
.quiz-actions { display: flex; gap: 10px; flex-wrap: wrap; margin: 20px 0; }

/* ---------- Buttons ---------- */
.btn { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; border: none;
  background: var(--accent); color: #fff; padding: 10px 20px; border-radius: 24px; font-weight: 700;
  font-size: .92rem; text-decoration: none; transition: .15s; }
.btn:hover { background: var(--accent-hover); }
.btn.ghost { background: transparent; color: var(--accent); border: 1.5px solid var(--accent); }
.btn.ghost:hover { background: var(--bg-soft); }

/* ---------- Timeline (roadmap) ---------- */
.timeline { position: relative; margin: 24px 0; padding-left: 32px; }
.timeline::before { content: ""; position: absolute; left: 9px; top: 0; bottom: 0; width: 2px; background: var(--border); }
.tl-item { position: relative; margin-bottom: 22px; }
.tl-item::before { content: ""; position: absolute; left: -28px; top: 4px; width: 16px; height: 16px;
  border-radius: 50%; background: var(--accent); border: 3px solid var(--bg); }
.tl-item .tl-week { font-size: .78rem; font-weight: 700; color: var(--accent); }

/* ---------- Tabs ---------- */
.tabs { display: flex; gap: 6px; border-bottom: 1px solid var(--border); margin: 20px 0 0; flex-wrap: wrap; }
.tab-btn { cursor: pointer; padding: 10px 18px; border: none; background: transparent; color: var(--text-soft);
  font-weight: 700; font-size: .92rem; border-bottom: 3px solid transparent; }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-panel { display: none; padding: 20px 0; }
.tab-panel.active { display: block; }

/* ---------- Tooltip (glossary hover) ---------- */
.term { border-bottom: 1.5px dotted var(--accent); cursor: help; position: relative; }
.term:hover::after {
  content: attr(data-tip); position: absolute; left: 0; bottom: 130%; z-index: 50;
  background: #1f2733; color: #fff; padding: 8px 12px; border-radius: 8px; font-size: .82rem;
  width: max-content; max-width: 280px; line-height: 1.5; box-shadow: var(--shadow-lg); white-space: normal;
}

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--border); padding: 28px 24px; text-align: center; color: var(--text-soft); font-size: .85rem; }

/* ---------- Donut (exam weight) ---------- */
.donut-legend { display: flex; flex-direction: column; gap: 8px; justify-content: center; }
.donut-legend .lg { display: flex; align-items: center; gap: 8px; font-size: .9rem; }
.donut-legend .sw { width: 14px; height: 14px; border-radius: 4px; }

/* ---------- Back to top ---------- */
#toTop { position: fixed; right: 24px; bottom: 24px; width: 46px; height: 46px; border-radius: 50%;
  background: var(--accent); color: #fff; border: none; cursor: pointer; font-size: 1.2rem; box-shadow: var(--shadow-lg);
  opacity: 0; pointer-events: none; transition: opacity .3s; z-index: 90; }
#toTop.show { opacity: 1; pointer-events: auto; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .toc { display: none; }
  .grid.cols-3, .grid.cols-5, .grid.cols-2 { grid-template-columns: 1fr; }
  .topbar nav { display: none; }
  .hero h1 { font-size: 1.7rem; }
}

/* ---------- Print ---------- */
@media print {
  .topbar, .toc, #toTop, .theme-toggle, .quiz-actions { display: none; }
  body { background: #fff; }
  details[open] .detail-body, .quiz-explain { display: block !important; }
}

/* =====================================================================
   PCD 拡張スタイル — リッチ表現用 (タブ/アコーディオン/リスク/選択ツリー/SVG)
   ===================================================================== */

/* ---------- Tabs ---------- */
.tabs { margin: 18px 0; }
.tab-list {
  display: flex; gap: 4px; border-bottom: 2px solid var(--border);
  list-style: none; padding: 0; margin: 0; overflow-x: auto;
}
.tab-list label {
  cursor: pointer; padding: 10px 18px; font-weight: 600; font-size: .92rem;
  color: var(--text-soft); border-bottom: 2px solid transparent; margin-bottom: -2px;
  white-space: nowrap; transition: color .15s, border-color .15s;
}
.tab-list label:hover { color: var(--accent); }
.tabs input[type="radio"] { display: none; }
.tabs input[type="radio"]:checked + label {
  color: var(--accent); border-bottom-color: var(--accent);
}
.tab-panel { display: none; padding: 18px 0; }
/* 各タブパネルは直前の radio が checked のとき表示。HTML 側で input → label → panel の順に並べる */
.tabs input[type="radio"][data-tab="t1"]:checked ~ .tab-panel[data-panel="t1"],
.tabs input[type="radio"][data-tab="t2"]:checked ~ .tab-panel[data-panel="t2"],
.tabs input[type="radio"][data-tab="t3"]:checked ~ .tab-panel[data-panel="t3"],
.tabs input[type="radio"][data-tab="t4"]:checked ~ .tab-panel[data-panel="t4"],
.tabs input[type="radio"][data-tab="t5"]:checked ~ .tab-panel[data-panel="t5"] {
  display: block;
}

/* ---------- Accordion (details/summary 強化) ---------- */
details.acc {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 0; margin: 10px 0; overflow: hidden;
}
details.acc summary {
  cursor: pointer; padding: 14px 18px; font-weight: 600; list-style: none;
  display: flex; justify-content: space-between; align-items: center;
  background: var(--bg-soft); transition: background .15s;
}
details.acc summary::-webkit-details-marker { display: none; }
details.acc summary::after { content: "▾"; transition: transform .2s; color: var(--text-soft); }
details.acc[open] summary { background: var(--bg-soft); border-bottom: 1px solid var(--border); }
details.acc[open] summary::after { transform: rotate(180deg); }
details.acc summary:hover { background: var(--bg-soft); }
details.acc .acc-body { padding: 14px 18px 18px; }
details.acc .acc-body p:first-child { margin-top: 0; }
details.acc .acc-body p:last-child { margin-bottom: 0; }

/* ---------- Risk / Pitfall Boxes (色分け) ---------- */
.risk {
  border-radius: var(--radius-sm); padding: 14px 18px 14px 50px; margin: 18px 0;
  position: relative; background: rgba(234,67,53,.06); border-left: 4px solid var(--g-red);
}
.risk::before {
  content: "⚠️"; position: absolute; left: 14px; top: 14px; font-size: 1.4rem;
}
.risk .ttl { font-weight: 700; color: var(--g-red); margin-bottom: 6px; display: block; }
[data-theme="dark"] .risk { background: rgba(234,67,53,.1); }

.pitfall {
  border-radius: var(--radius-sm); padding: 14px 18px 14px 50px; margin: 18px 0;
  position: relative; background: rgba(251,188,4,.08); border-left: 4px solid var(--g-yellow);
}
.pitfall::before {
  content: "🪤"; position: absolute; left: 14px; top: 14px; font-size: 1.4rem;
}
.pitfall .ttl { font-weight: 700; color: #a67c00; margin-bottom: 6px; display: block; }
[data-theme="dark"] .pitfall .ttl { color: #fbbc04; }
[data-theme="dark"] .pitfall { background: rgba(251,188,4,.12); }

.bestpractice {
  border-radius: var(--radius-sm); padding: 14px 18px 14px 50px; margin: 18px 0;
  position: relative; background: rgba(52,168,83,.07); border-left: 4px solid var(--g-green);
}
.bestpractice::before {
  content: "✅"; position: absolute; left: 14px; top: 14px; font-size: 1.4rem;
}
.bestpractice .ttl { font-weight: 700; color: var(--g-green); margin-bottom: 6px; display: block; }
[data-theme="dark"] .bestpractice { background: rgba(52,168,83,.1); }

.officialref {
  border-radius: var(--radius-sm); padding: 12px 16px 12px 46px; margin: 14px 0;
  position: relative; background: rgba(66,133,244,.06); border-left: 4px solid var(--g-blue);
  font-size: .92rem;
}
.officialref::before {
  content: "📖"; position: absolute; left: 12px; top: 12px; font-size: 1.2rem;
}
.officialref .ttl { font-weight: 700; color: var(--g-blue-deep); margin-bottom: 4px; display: block; }
[data-theme="dark"] .officialref .ttl { color: #aecbfa; }
[data-theme="dark"] .officialref { background: rgba(66,133,244,.1); }

/* ---------- Decision Tree (選択ツリー) ---------- */
.dtree {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 18px; margin: 18px 0;
}
.dtree-node {
  padding: 10px 14px; margin: 8px 0; background: var(--bg-soft); border-radius: 6px;
  border-left: 3px solid var(--g-blue); display: flex; align-items: center; gap: 10px;
}
.dtree-node.q { background: rgba(66,133,244,.1); border-left-color: var(--g-blue); font-weight: 600; }
.dtree-node.a { background: rgba(52,168,83,.08); border-left-color: var(--g-green); }
.dtree-node.warn { background: rgba(251,188,4,.1); border-left-color: var(--g-yellow); }
.dtree-children { margin-left: 24px; border-left: 2px dashed var(--border); padding-left: 16px; }
.dtree-result {
  display: inline-block; padding: 4px 12px; border-radius: 12px; font-weight: 700;
  background: var(--g-green); color: #fff; font-size: .85rem; margin-left: 8px;
}

/* ---------- Comparison Cards (比較表をカード化) ---------- */
.compare-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 14px; margin: 18px 0;
}
.compare-card {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 18px; position: relative;
}
.compare-card.recommended { border: 2px solid var(--g-green); }
.compare-card.recommended::before {
  content: "推奨"; position: absolute; top: -10px; right: 12px; background: var(--g-green);
  color: #fff; font-size: .72rem; padding: 2px 10px; border-radius: 10px; font-weight: 700;
}
.compare-card h4 { margin: 0 0 10px; color: var(--accent); font-size: 1.05rem; }
.compare-card ul { padding-left: 1.2em; margin: 8px 0 0; font-size: .9rem; }
.compare-card .verdict {
  margin-top: 12px; padding-top: 10px; border-top: 1px dashed var(--border);
  font-size: .85rem; color: var(--text-soft);
}

/* ---------- Architecture SVG container ---------- */
.svg-fig {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 24px; margin: 18px 0; text-align: center;
}
.svg-fig svg { max-width: 100%; height: auto; }
.svg-fig .caption {
  margin-top: 10px; font-size: .85rem; color: var(--text-soft); font-style: italic;
}
.svg-fig text { fill: var(--text); font-family: var(--font); font-size: 13px; }
[data-theme="dark"] .svg-fig text { fill: var(--text); }

/* ---------- KPI grid ---------- */
.kpi-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px; margin: 14px 0;
}
.kpi {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 14px; text-align: center;
}
.kpi .val { font-size: 1.8rem; font-weight: 800; color: var(--accent); line-height: 1.1; }
.kpi .lbl { font-size: .78rem; color: var(--text-soft); margin-top: 4px; text-transform: uppercase; letter-spacing: .05em; }

/* ---------- Inline language badge ---------- */
pre[data-lang]::before {
  content: attr(data-lang);
  display: inline-block; background: var(--g-blue); color: #fff;
  font-size: .68rem; font-weight: 700; padding: 2px 8px; border-radius: 0 0 6px 0;
  position: absolute; top: 0; left: 0; text-transform: uppercase; letter-spacing: .05em;
}
pre { position: relative; }

/* ---------- Sidebar (左ナビ) — section pages ---------- */
.layout .sidebar { /* override .toc if used differently */ }
.sidebar {
  position: sticky; top: 80px; align-self: flex-start;
  width: var(--sidebar-w); flex-shrink: 0;
  max-height: calc(100vh - 100px); overflow-y: auto;
  padding: 18px; margin-top: 32px;
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  font-size: .9rem;
}
.sidebar h4 { margin: 0 0 10px; font-size: .78rem; letter-spacing: .08em; text-transform: uppercase; color: var(--text-soft); }
.sidebar ul { list-style: none; padding: 0; margin: 0; }
.sidebar li { margin: 0; }
.sidebar a { display: block; color: var(--text-soft); text-decoration: none; padding: 5px 10px; border-radius: 6px; border-left: 2px solid transparent; }
.sidebar a:hover { background: var(--bg-soft); color: var(--accent); }
.sidebar a.active { color: var(--accent); border-left-color: var(--accent); background: var(--bg-soft); font-weight: 600; }

/* ---------- Sequence callout (横並び：cause → effect) ---------- */
.seq {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 12px; align-items: center;
  margin: 14px 0; padding: 14px; background: var(--bg-soft); border-radius: var(--radius-sm);
}
.seq .box { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 6px; padding: 12px; }
.seq .arr { font-size: 1.5rem; color: var(--accent); text-align: center; font-weight: 700; }
.seq .box h5 { margin: 0 0 6px; font-size: .9rem; color: var(--accent); }
.seq .box p { margin: 0; font-size: .85rem; }

/* ---------- Glossary tooltip (用語ホバー説明) ---------- */
.term {
  border-bottom: 1px dotted var(--accent); cursor: help; position: relative;
}
.term:hover::after {
  content: attr(data-tip);
  position: absolute; left: 0; top: calc(100% + 6px); z-index: 50;
  background: #1f2733; color: #fff; padding: 8px 12px; border-radius: 6px;
  font-size: .82rem; white-space: nowrap; max-width: 320px; white-space: normal; width: max-content;
  box-shadow: var(--shadow-lg); font-weight: normal;
}

/* ---------- Postmortem (事故ケース) ---------- */
.postmortem {
  background: var(--bg-elev); border: 1px solid var(--border); border-left: 5px solid var(--g-red);
  border-radius: var(--radius-sm); padding: 20px 24px; margin: 22px 0;
  position: relative;
}
.postmortem .pm-header {
  display: flex; align-items: center; gap: 10px; margin-bottom: 14px;
  padding-bottom: 12px; border-bottom: 1px dashed var(--border);
}
.postmortem .pm-tag {
  background: var(--g-red); color: #fff; font-size: .7rem; font-weight: 700;
  padding: 3px 10px; border-radius: 10px; letter-spacing: .05em;
}
.postmortem .pm-service {
  background: var(--bg-soft); color: var(--text); font-size: .78rem; font-weight: 600;
  padding: 3px 10px; border-radius: 10px; border: 1px solid var(--border);
}
.postmortem .pm-severity {
  font-size: .76rem; font-weight: 700; padding: 3px 8px; border-radius: 8px;
}
.postmortem .pm-severity.sev-critical { background: rgba(234,67,53,.2); color: #c5221f; }
.postmortem .pm-severity.sev-high     { background: rgba(251,188,4,.25); color: #a67c00; }
.postmortem .pm-severity.sev-medium   { background: rgba(66,133,244,.18); color: var(--g-blue-deep); }
[data-theme="dark"] .postmortem .pm-severity.sev-critical { color: #f28b82; }
[data-theme="dark"] .postmortem .pm-severity.sev-high     { color: #fdd663; }
[data-theme="dark"] .postmortem .pm-severity.sev-medium   { color: #aecbfa; }
.postmortem h4 {
  margin: 0 0 4px; font-size: 1.05rem; font-weight: 700;
}
.postmortem .pm-section {
  margin: 14px 0 0; padding: 10px 14px; border-radius: 6px;
  background: var(--bg-soft); border-left: 3px solid var(--accent);
}
.postmortem .pm-section .pm-label {
  display: inline-block; font-weight: 700; font-size: .78rem;
  text-transform: uppercase; letter-spacing: .08em; color: var(--text-soft);
  margin-bottom: 4px;
}
.postmortem .pm-symptom .pm-label   { color: var(--g-red); }
.postmortem .pm-cause .pm-label     { color: var(--g-yellow); }
.postmortem .pm-impact .pm-label    { color: #a67c00; }
.postmortem .pm-recovery .pm-label  { color: var(--g-blue); }
.postmortem .pm-prevent .pm-label   { color: var(--g-green); }

.postmortem .pm-symptom  { border-left-color: var(--g-red); }
.postmortem .pm-cause    { border-left-color: var(--g-yellow); }
.postmortem .pm-impact   { border-left-color: #a67c00; }
.postmortem .pm-recovery { border-left-color: var(--g-blue); }
.postmortem .pm-prevent  { border-left-color: var(--g-green); }

.postmortem .pm-section p { margin: 4px 0; }
.postmortem .pm-section ul, .postmortem .pm-section ol {
  margin: 4px 0 4px 1em; padding-left: 1em;
}
.postmortem .pm-section li { margin: 3px 0; }
.postmortem .pm-section code:not(pre code) { font-size: .85em; }

/* Incidents セクション全体の背景 */
.incidents-intro {
  background: linear-gradient(135deg, rgba(234,67,53,.06), rgba(251,188,4,.05));
  border-radius: var(--radius); padding: 16px 20px; margin: 18px 0 24px;
  border: 1px solid var(--border);
}
[data-theme="dark"] .incidents-intro {
  background: linear-gradient(135deg, rgba(234,67,53,.1), rgba(251,188,4,.08));
}

/* ---------- Responsive 追加 ---------- */
@media (max-width: 900px) {
  .sidebar { display: none; }
  .seq { grid-template-columns: 1fr; }
  .seq .arr { transform: rotate(90deg); }
  .compare-grid { grid-template-columns: 1fr; }
  .postmortem .pm-header { flex-wrap: wrap; }
}