:root {
      --ink: #06131f;
      --paper: #ffffff;
      --line: #dbe3ea;
      --muted: #4b5563;
      --signal: #0b63ce;
      --font-sans: HelveticaNeue, "Helvetica Neue", Helvetica, Arial,
        "游ゴシック体", YuGothic, "游ゴシック Medium", "Yu Gothic Medium",
        "游ゴシック", "Yu Gothic", "ヒラギノ角ゴ ProN W3", "Hiragino Kaku Gothic ProN",
        "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "MS ゴシック", "MS Gothic",
        sans-serif;
      --font-mono: "SF Mono", "Fira Code", "Fira Mono", Menlo, Consolas, monospace;
      font-family: var(--font-sans);
      color: var(--ink);
      background: var(--paper);
    }

    * { box-sizing: border-box; }

    html { scroll-behavior: smooth; }

    body {
      margin: 0;
      font-size: 16px;
      line-height: 1.8;
      font-feature-settings: "palt";
      -webkit-font-smoothing: antialiased;
      word-wrap: break-word;
      background: #f8f7f2;
    }

    a { color: inherit; text-decoration: none; }
    img { display: block; max-width: 100%; height: auto; }

    .site-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 18px;
      min-height: 62px;
      padding: 14px clamp(20px, 4vw, 58px) 10px;
      background: #f8f7f2;
      box-shadow: inset 0 -1px 0 rgba(6, 19, 31, 0.08);
    }

    .brand {
      display: inline-flex;
      align-items: center;
      gap: 7px;
    }

    .brand-symbol { width: 40px; }
    .brand-wordmark { width: 96px; }

    .back-link {
      font-family: var(--font-mono);
      font-size: 11px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .back-link:hover,
    .back-link:focus-visible {
      color: var(--signal);
      outline: none;
    }

    main {
      max-width: 760px;
      margin: 0 auto;
      padding: clamp(40px, 7vw, 88px) clamp(20px, 4vw, 40px) clamp(60px, 9vw, 120px);
    }

    .breadcrumb {
      margin-bottom: 18px;
      color: var(--muted);
      font-family: var(--font-mono);
      font-size: 11px;
      font-weight: 780;
      letter-spacing: 0.06em;
    }

    .breadcrumb a {
      text-decoration: underline;
      text-underline-offset: 3px;
    }

    .breadcrumb a:hover,
    .breadcrumb a:focus-visible {
      color: var(--signal);
      outline: none;
    }

    .section-label {
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 12px;
      font-weight: 780;
      letter-spacing: 0.1em;
      text-transform: uppercase;
    }

    h1 {
      margin: 14px 0 10px;
      font-size: clamp(28px, 4vw, 40px);
      font-weight: 820;
      line-height: 1.3;
      letter-spacing: 0.02em;
    }

    .page-meta {
      margin: 0 0 28px;
      color: var(--muted);
      font-family: var(--font-mono);
      font-size: 12px;
      letter-spacing: 0.04em;
    }

    .summary-box {
      margin: 0 0 44px;
      padding: 22px 26px;
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .summary-box b {
      display: block;
      margin-bottom: 10px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 12px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .summary-box ul {
      margin: 0;
      padding-left: 1.4em;
    }

    .summary-box li { margin-bottom: 6px; }

    .toc {
      margin: 0 0 44px;
      padding: 20px 24px;
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .toc b {
      display: block;
      margin-bottom: 10px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 12px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .toc ol {
      margin: 0;
      padding-left: 1.4em;
    }

    .toc li { margin-bottom: 4px; }

    section {
      margin-bottom: 34px;
      padding-top: 22px;
      border-top: 1px solid var(--ink);
    }

    h2 {
      margin: 0 0 12px;
      font-size: clamp(20px, 2.4vw, 24px);
      font-weight: 820;
      letter-spacing: 0.02em;
      line-height: 1.4;
    }

    h3 {
      margin: 24px 0 8px;
      font-size: 17px;
      font-weight: 820;
      letter-spacing: 0.02em;
      line-height: 1.5;
    }

    p, ul, ol { margin: 0 0 12px; color: var(--ink); }
    ul, ol { padding-left: 1.4em; }
    li { margin-bottom: 4px; }

    main strong {
      font-weight: 780;
      color: var(--ink);
    }

    main a {
      color: var(--ink);
      text-decoration: underline;
      text-underline-offset: 3px;
    }

    main a:hover,
    main a:focus-visible {
      color: var(--signal);
      outline: none;
    }

    .figure {
      margin: 20px 0 6px;
      padding: 24px 22px;
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .figure figcaption {
      margin-bottom: 18px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 12px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .spec-track {
      position: relative;
      height: 4px;
      margin: 0 8px 26px;
      background: linear-gradient(90deg, var(--line) 0%, var(--signal) 100%);
    }

    .spec-track::after {
      content: "";
      position: absolute;
      right: -8px;
      top: -4px;
      border-left: 8px solid var(--signal);
      border-top: 6px solid transparent;
      border-bottom: 6px solid transparent;
    }

    .spec-dot {
      position: absolute;
      top: -5px;
      width: 14px;
      height: 14px;
      border-radius: 50%;
      background: var(--paper);
      border: 3px solid var(--ink);
      transform: translateX(-50%);
    }

    .spec-dot.s2 { border-color: var(--signal); }
    .spec-dot.s3 { background: var(--signal); border-color: var(--signal); }

    .spec-cols {
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 12px;
    }

    .spec-en {
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.06em;
      text-transform: uppercase;
    }

    .spec-col b {
      display: block;
      font-size: 14.5px;
      font-weight: 820;
      line-height: 1.5;
    }

    .spec-col p {
      margin: 4px 0 0;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.7;
    }

    .spec-axis {
      margin: 18px 0 0;
      text-align: right;
      color: var(--muted);
      font-family: var(--font-mono);
      font-size: 10.5px;
      letter-spacing: 0.06em;
    }

    .chain-flow { display: flex; flex-direction: column; }

    .chain-node {
      display: flex;
      align-items: flex-start;
      gap: 14px;
      padding: 14px 16px;
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .chain-node.chain-origin { background: var(--ink); color: #fff; }
    .chain-node.chain-origin .chain-desc { color: rgba(255, 255, 255, 0.75); }
    .chain-node.chain-origin .chain-num { border-color: rgba(255, 255, 255, 0.6); font-size: 16px; }
    .chain-node.chain-origin .chain-title small { color: #9cc4f5; }

    .chain-num {
      flex: none;
      width: 34px;
      height: 34px;
      display: grid;
      place-items: center;
      border: 1px solid currentColor;
      border-radius: 50%;
      font-family: var(--font-mono);
      font-size: 12px;
      font-weight: 780;
    }

    .chain-body { min-width: 0; }

    .chain-title {
      margin: 0;
      font-size: 15.5px;
      font-weight: 820;
      line-height: 1.5;
      color: inherit;
    }

    .chain-title small {
      margin-left: 8px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.06em;
      text-transform: uppercase;
    }

    .chain-desc {
      margin: 0;
      color: var(--muted);
      font-size: 12.5px;
      line-height: 1.7;
    }

    .chain-link {
      align-self: center;
      height: 26px;
      display: grid;
      place-items: center;
      color: var(--signal);
      font-size: 15px;
      line-height: 1;
    }

    .chain-brake {
      display: flex;
      gap: 10px;
      align-items: baseline;
      margin: 16px 0 0;
      padding: 12px 16px;
      border: 1px dashed var(--muted);
      color: var(--muted);
      font-size: 12.5px;
      line-height: 1.7;
    }

    .chain-brake b {
      flex: none;
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.06em;
      text-transform: uppercase;
    }

    .chain-duo {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      gap: 8px;
      align-items: stretch;
    }

    .chain-duo .chain-node { height: 100%; }

    .chain-duo-link {
      align-self: center;
      color: var(--signal);
      font-size: 17px;
      font-weight: 700;
      line-height: 1;
    }

    .chain-duo-note {
      margin: 6px 0 0;
      text-align: center;
      color: var(--muted);
      font-size: 11.5px;
    }

    .tl-wrap { overflow-x: auto; }

    .tl-table {
      width: 100%;
      border-collapse: collapse;
      font-size: 13px;
      line-height: 1.7;
    }

    .tl-table th,
    .tl-table td {
      border: 1px solid var(--line);
      padding: 8px 12px;
      text-align: left;
      vertical-align: top;
    }

    .tl-table th {
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      color: var(--muted);
      white-space: nowrap;
    }

    .tl-table td:first-child {
      font-weight: 820;
      white-space: nowrap;
    }

    .tl-note {
      margin: 14px 0 0;
      color: var(--muted);
      font-size: 12.5px;
    }

    .topic-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      margin-bottom: 12px;
    }

    .layer-stack {
      display: flex;
      flex-direction: column;
      margin-bottom: 12px;
    }

    .layer-band,
    .topic-card {
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .layer-band { padding: 16px 20px; }

    .layer-band + .layer-band { border-top: 0; }

    .layer-head {
      display: flex;
      flex-wrap: wrap;
      align-items: baseline;
      gap: 4px 12px;
      margin-bottom: 6px;
    }

    .layer-no {
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      white-space: nowrap;
    }

    .layer-head > b {
      font-size: 15px;
      font-weight: 820;
      line-height: 1.5;
    }

    .layer-desc {
      margin: 0;
      color: var(--muted);
      font-size: 12.5px;
      line-height: 1.7;
    }

    .layer-sub {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px 20px;
      margin-top: 4px;
    }

    .layer-sub b {
      display: block;
      font-size: 13.5px;
      font-weight: 820;
      margin-bottom: 3px;
    }

    .topic-grid.cols3 { grid-template-columns: 1fr 1fr 1fr; }

    .topic-card { padding: 16px 18px; }

    .topic-tag {
      display: block;
      margin-bottom: 6px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .topic-card b {
      display: block;
      font-size: 15px;
      font-weight: 820;
      margin-bottom: 4px;
    }

    .topic-card p {
      margin: 0;
      color: var(--muted);
      font-size: 12.5px;
      line-height: 1.7;
    }

    .concept-figure {
      margin: 26px 0 34px;
      overflow: hidden;
      border: 1px solid var(--ink);
      background: var(--paper);
    }

    .concept-figure img {
      width: 100%;
      background: #e7ecf0;
    }

    .concept-caption {
      padding: 15px 18px 17px;
      border-top: 1px solid var(--ink);
    }

    .concept-caption-label {
      display: block;
      margin-bottom: 5px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .concept-caption p {
      margin: 0;
      color: var(--muted);
      font-size: 12.5px;
      line-height: 1.75;
    }

    .regional-visions {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .regional-visions img {
      aspect-ratio: 1 / 1;
      height: auto;
      object-fit: cover;
    }

    .regional-visions img:first-child {
      object-position: center 58%;
      border-right: 1px solid var(--ink);
    }

    .ai2040-reading {
      display: grid;
      grid-template-columns: minmax(0, 1fr) auto;
      align-items: center;
      gap: 24px;
      margin: -2px 0 34px;
      padding: 22px 24px;
      border: 1px solid var(--ink);
      border-left: 4px solid var(--signal);
      background: var(--paper);
      text-decoration: none;
    }

    main a.ai2040-reading { text-decoration: none; }

    .ai2040-reading:hover,
    .ai2040-reading:focus-visible {
      background: #f0f4f8;
      outline: none;
    }

    .ai2040-reading-kicker {
      display: block;
      margin-bottom: 5px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .ai2040-reading-title {
      display: block;
      margin-bottom: 5px;
      font-size: 19px;
      font-weight: 820;
      line-height: 1.45;
    }

    .ai2040-reading-desc {
      display: block;
      max-width: 540px;
      color: var(--muted);
      font-size: 13px;
      line-height: 1.75;
    }

    .ai2040-reading-cta {
      display: block;
      margin-top: 10px;
      color: var(--signal);
      font-size: 13px;
      font-weight: 780;
    }

    .ai2040-reading-mark {
      min-width: 86px;
      padding-left: 20px;
      border-left: 1px solid var(--line);
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 28px;
      font-weight: 850;
      line-height: 1;
      text-align: right;
    }

    .ai2040-reading--book {
      grid-template-columns: auto minmax(0, 1fr);
      gap: 28px;
    }

    .ai2040-reading-cover {
      display: block;
      width: 108px;
      flex: none;
    }

    .ai2040-reading-cover img {
      display: block;
      width: 100%;
      height: auto;
      border: 1px solid rgba(6, 19, 31, 0.18);
      box-shadow: 0 12px 26px rgba(6, 19, 31, 0.16), 0 2px 6px rgba(6, 19, 31, 0.1);
    }

    .intro-cta {
      margin-top: 48px;
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 12px;
    }

    .exit-card {
      display: block;
      padding: 16px 18px;
      border: 1px solid var(--ink);
      background: var(--paper);
      text-decoration: none;
    }

    main a.exit-card { text-decoration: none; }

    .exit-card:hover,
    .exit-card:focus-visible { background: #f0f4f8; outline: none; }

    .exit-tag {
      display: block;
      margin-bottom: 6px;
      color: var(--signal);
      font-family: var(--font-mono);
      font-size: 10.5px;
      font-weight: 780;
      letter-spacing: 0.08em;
      text-transform: uppercase;
    }

    .exit-card b {
      display: block;
      font-size: 14.5px;
      font-weight: 820;
      margin-bottom: 2px;
    }

    .exit-desc { color: var(--muted); font-size: 12px; }

    .exit-arrow {
      display: block;
      margin-top: 10px;
      color: var(--signal);
      font-weight: 700;
    }

    @media (max-width: 620px) {
      .spec-track { display: none; }
      .spec-cols { grid-template-columns: 1fr; gap: 8px; }
      .chain-duo { grid-template-columns: 1fr; }
      .chain-duo-link { justify-self: center; transform: rotate(90deg); }
      .layer-sub { grid-template-columns: 1fr; }
      .topic-grid,
      .topic-grid.cols3,
      .intro-cta { grid-template-columns: 1fr; }
      .ai2040-reading {
        grid-template-columns: 1fr;
        gap: 0;
        padding: 19px 20px;
      }
      .ai2040-reading-mark { display: none; }
      .ai2040-reading--book {
        grid-template-columns: auto minmax(0, 1fr);
        gap: 14px;
      }
      .ai2040-reading-cover { width: 64px; }
    }

    @media (max-width: 360px) {
      .ai2040-reading--book { grid-template-columns: 1fr; }
      .ai2040-reading-cover { width: 84px; margin-bottom: 12px; }
    }

    .site-footer {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: space-between;
      gap: 10px 16px;
      padding: 18px clamp(20px, 4vw, 58px);
      background: linear-gradient(180deg, #eef2f5 0%, #f8f7f2 62%);
      box-shadow: inset 0 1px 0 rgba(6, 19, 31, 0.08);
      color: var(--muted);
      font-family: var(--font-mono);
      font-size: 11px;
      font-weight: 850;
      letter-spacing: 0.04em;
      text-transform: uppercase;
    }

    .site-footer a:hover,
    .site-footer a:focus-visible {
      color: var(--signal);
      outline: none;
    }