/* ============================================================
   AI実験ノート — 共通スタイル（外部CDN不使用・システムフォントのみ）
   トークン運用：
     - :root                                             = ライトの正
     - @media (prefers-color-scheme: dark) + :not([data-theme="light"]) = OSがダークのときの初期値
     - [data-theme="dark"] / [data-theme="light"]         = 右上トグルの手動指定（勝つ）
   ============================================================ */

:root {
  /* --- 色（ライト）--- */
  --bg: #f2f4ee;
  --bg-raised: #fbfcf9;
  --bg-sunken: #e9ebe3;
  --ink: #1d2420;
  --ink-muted: #5b665f;
  --ink-faint: #8b968e;
  --line: #d8dccf;
  --line-strong: #b9c0af;
  --accent: #2f6f63;
  --accent-strong: #1c4a41;
  --accent-soft: #e2ede8;
  --accent-ink: #f4faf7;
  --code-bg: #e9e9e0;
  --shadow: rgba(29, 36, 32, 0.08);

  /* --- 文字 --- */
  --font-display: "Hiragino Mincho ProN", "Yu Mincho", YuMincho, "MS PMincho",
    serif;
  --font-body: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic UI",
    "Yu Gothic", "Meiryo", system-ui, -apple-system, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Consolas, "Courier New", monospace;

  /* --- 寸法 --- */
  --measure: 34em; /* 本文の最大幅（日本語で概ね68〜72字） */
  --radius: 3px;
  --sidebar-w: 236px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #14181a;
    --bg-raised: #1a1f21;
    --bg-sunken: #0f1213;
    --ink: #e6e9e2;
    --ink-muted: #a2ada4;
    --ink-faint: #737d75;
    --line: #2b322e;
    --line-strong: #3c453f;
    --accent: #7fc9b6;
    --accent-strong: #a9dfcd;
    --accent-soft: #1c2b27;
    --accent-ink: #0d1513;
    --code-bg: #1f2422;
    --shadow: rgba(0, 0, 0, 0.35);
  }
}

:root[data-theme="dark"] {
  --bg: #14181a;
  --bg-raised: #1a1f21;
  --bg-sunken: #0f1213;
  --ink: #e6e9e2;
  --ink-muted: #a2ada4;
  --ink-faint: #737d75;
  --line: #2b322e;
  --line-strong: #3c453f;
  --accent: #7fc9b6;
  --accent-strong: #a9dfcd;
  --accent-soft: #1c2b27;
  --accent-ink: #0d1513;
  --code-bg: #1f2422;
  --shadow: rgba(0, 0, 0, 0.35);
}

/* ============================================================
   リセット最小限
   ============================================================ */

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.9;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  max-width: 100%;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}

a:hover {
  color: var(--accent);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}

/* ============================================================
   ヘッダー
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.5rem;
  background: var(--bg-raised);
  border-bottom: 1px solid var(--line);
}

.site-brand {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  text-decoration: none;
  color: var(--ink);
}

.site-brand__name {
  font-family: var(--font-display);
  font-size: 1.15rem;
  letter-spacing: 0.04em;
}

.site-brand__tagline {
  font-size: 0.72rem;
  color: var(--ink-faint);
  letter-spacing: 0.03em;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.theme-toggle {
  appearance: none;
  border: 1px solid var(--line-strong);
  background: var(--bg);
  color: var(--ink);
  border-radius: 999px;
  width: 2.1rem;
  height: 2.1rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 0.95rem;
  line-height: 1;
}

.theme-toggle:hover {
  border-color: var(--accent);
}

/* ============================================================
   全体レイアウト（サイドバー＋本文）
   ============================================================ */

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  max-width: 1120px;
  margin: 0 auto;
}

.sidebar {
  padding: 2rem 1.25rem 3rem;
  border-right: 1px solid var(--line);
}

.sidebar-section + .sidebar-section {
  margin-top: 1.6rem;
}

.sidebar-section__label {
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--ink-faint);
  margin: 0 0 0.5rem;
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.sidebar-list a {
  display: block;
  padding: 0.3rem 0.5rem;
  border-radius: var(--radius);
  color: var(--ink-muted);
  text-decoration: none;
  font-size: 0.88rem;
  border-left: 2px solid transparent;
}

.sidebar-list a:hover {
  background: var(--accent-soft);
  color: var(--ink);
}

.sidebar-list a[aria-current="page"] {
  color: var(--accent-strong);
  border-left-color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

.nav-toggle {
  display: none;
}

.sidebar-body--wide {
  display: block;
}

/* ============================================================
   本文
   ============================================================ */

main {
  padding: 2.5rem 2rem 5rem;
  min-width: 0;
}

.content-inner {
  max-width: var(--measure);
  margin: 0 auto;
}

.breadcrumb {
  font-size: 0.78rem;
  color: var(--ink-faint);
  margin: 0 0 1.1rem;
  letter-spacing: 0.02em;
}

.breadcrumb a {
  color: var(--ink-faint);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--accent-strong);
}

.page-eyebrow {
  display: inline-block;
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--accent-strong);
  background: var(--accent-soft);
  padding: 0.2em 0.65em;
  border-radius: 999px;
  margin-bottom: 0.9rem;
}

h1.page-title {
  font-family: var(--font-display);
  font-size: 1.95rem;
  line-height: 1.5;
  margin: 0 0 0.9rem;
  text-wrap: balance;
  letter-spacing: 0.01em;
}

.page-summary {
  font-size: 1.02rem;
  color: var(--ink-muted);
  border-left: 3px solid var(--accent);
  padding-left: 1rem;
  margin: 0 0 2.2rem;
}

.prose h2 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  margin: 2.6rem 0 1rem;
  padding-top: 0.4rem;
  border-top: 1px solid var(--line);
  letter-spacing: 0.01em;
}

.prose h2:first-child {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

.prose h3 {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 1.05rem;
  margin: 1.8rem 0 0.7rem;
  color: var(--ink);
}

.prose p {
  margin: 0 0 1.25rem;
}

.prose ul,
.prose ol {
  margin: 0 0 1.25rem;
  padding-left: 1.4rem;
}

.prose li {
  margin: 0 0 0.5rem;
}

.prose li::marker {
  color: var(--accent);
}

.prose strong {
  color: var(--ink);
}

.prose blockquote {
  margin: 0 0 1.25rem;
  padding: 0.7rem 1.1rem;
  border-left: 3px solid var(--line-strong);
  background: var(--bg-sunken);
  color: var(--ink-muted);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.prose code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  padding: 0.1em 0.35em;
  border-radius: var(--radius);
  font-size: 0.85em;
}

.prose a {
  text-decoration: underline;
}

.prose hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 2.4rem 0;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 1.5rem;
  font-size: 0.92rem;
}

.prose th,
.prose td {
  border: 1px solid var(--line);
  padding: 0.5em 0.7em;
  text-align: left;
  vertical-align: top;
}

.prose th {
  background: var(--bg-sunken);
  font-weight: 700;
}

/* ============================================================
   図解（figure/svg）
   ============================================================ */

figure.diagram {
  margin: 1.6rem 0 2.2rem;
  padding: 0.75rem 0.5rem 0.6rem;
  background: var(--bg-raised);
  border: 1px solid var(--line);
  border-radius: 6px;
  box-shadow: 0 1px 0 var(--shadow);
}

figure.diagram svg {
  display: block;
  width: 100%;
  height: auto;
  color: var(--ink);
}

figure.diagram .diagram-accent {
  color: var(--accent);
}

figure.diagram .diagram-muted {
  color: var(--ink-faint);
}

figure.diagram figcaption {
  margin-top: 0.75rem;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink-faint);
  border-top: 1px dashed var(--line);
  padding-top: 0.6rem;
}

/* ============================================================
   出典・脚注・ページ一覧カード
   ============================================================ */

.sources {
  margin: 0 0 1.5rem;
  padding: 1rem 1.2rem;
  background: var(--bg-sunken);
  border-radius: var(--radius);
  font-size: 0.88rem;
}

.sources__label {
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  margin: 0 0 0.5rem;
}

.sources ol {
  margin: 0;
  padding-left: 1.2rem;
}

.sources li {
  margin: 0 0 0.4rem;
  word-break: break-word;
}

.page-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0 2rem;
}

.page-card {
  display: block;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg-raised);
  text-decoration: none;
  color: var(--ink);
}

.page-card:hover {
  border-color: var(--accent);
}

.prose a.page-card,
.prose a.page-card:hover {
  text-decoration: none;
}

.page-card__section {
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  color: var(--accent-strong);
  margin: 0 0 0.4rem;
}

.page-card__title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  margin: 0 0 0.4rem;
  line-height: 1.5;
}

.page-card__summary {
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin: 0;
  line-height: 1.7;
}

/* ============================================================
   フッター
   ============================================================ */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 2rem;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.78rem;
  line-height: 1.8;
}

.site-footer strong {
  color: var(--ink-muted);
}

/* ============================================================
   レスポンシブ
   ============================================================ */

@media (max-width: 860px) {
  .layout {
    display: block;
  }

  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--line);
    padding: 0;
  }

  .nav-toggle {
    display: block;
  }

  .nav-toggle > summary {
    cursor: pointer;
    padding: 0.9rem 1.5rem;
    font-size: 0.85rem;
    color: var(--ink-muted);
    list-style: none;
  }

  .nav-toggle > summary::-webkit-details-marker {
    display: none;
  }

  .nav-toggle > summary::before {
    content: "目次 ▸ ";
    color: var(--accent-strong);
  }

  .nav-toggle[open] > summary::before {
    content: "目次 ▾ ";
  }

  .sidebar-body {
    padding: 0 1.5rem 1.5rem;
  }

  .sidebar-body--wide {
    display: none;
  }

  main {
    padding: 1.75rem 1.25rem 3rem;
  }

  h1.page-title {
    font-size: 1.6rem;
  }
}

@media (min-width: 861px) {
  .nav-toggle > summary {
    display: none;
  }
}

/* ============================================================
   印刷
   ============================================================ */

@media print {
  .site-header,
  .sidebar,
  .theme-toggle,
  .site-footer {
    display: none;
  }

  .layout {
    display: block;
    max-width: none;
  }

  main {
    padding: 0;
  }

  body {
    background: #fff;
    color: #000;
  }

  figure.diagram {
    border: 1px solid #999;
    box-shadow: none;
  }
}