:root {
      color-scheme: light;
      --ink: #16201d;
      --muted: #5b6964;
      --line: #d6dfda;
      --paper: #f8faf7;
      --panel: #ffffff;
      --teal: #0f766e;
      --teal-dark: #0b4f49;
      --gold: #b7791f;
      --rose: #b83258;
      --code: #101714;
      --code-2: #1d2a25;
      --soft: #edf5f2;
      --blue: #2563eb;
      --shadow: 0 20px 60px rgba(22, 32, 29, .10);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
    }

    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      color: var(--ink);
      background: var(--paper);
      line-height: 1.65;
    }
    a { color: var(--teal-dark); }
    button, input { font: inherit; }
    .shell {
      min-height: 100vh;
      display: grid;
      grid-template-columns: 240px minmax(0, 1fr);
    }
    aside {
      background: rgba(255,255,255,.9);
      backdrop-filter: blur(18px);
    }
    .global-menu {
      position: sticky;
      top: 0;
      grid-column: 1;
      height: 100vh;
      padding: 28px 20px;
      border-right: 1px solid var(--line);
      overflow: auto;
    }
    .local-panel {
      position: fixed;
      z-index: 35;
      top: 24px;
      right: 24px;
      width: 220px;
      max-height: calc(100vh - 48px);
      padding: 14px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: rgba(255,255,255,.86);
      box-shadow: 0 18px 48px rgba(22, 32, 29, .12);
      overflow: auto;
    }
    .local-title {
      margin: 0 0 12px;
      font-size: 13px;
      line-height: 1.3;
      font-weight: 900;
    }
    .menu-toggle {
      display: none;
      position: fixed;
      z-index: 60;
      top: 12px;
      left: 12px;
      width: 44px;
      height: 44px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      color: var(--ink);
      font-size: 22px;
      font-weight: 900;
      box-shadow: var(--shadow);
    }
    .menu-backdrop {
      display: none;
      position: fixed;
      inset: 0;
      z-index: 40;
      background: rgba(22, 32, 29, .24);
    }
    body.menu-open .menu-backdrop { display: block; }
    .brand {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 28px;
      font-weight: 800;
      letter-spacing: 0;
    }
    .mark {
      width: 38px;
      height: 38px;
      display: grid;
      place-items: center;
      border-radius: 8px;
      color: white;
      background: linear-gradient(135deg, var(--teal), #1f9f88);
      box-shadow: 0 12px 30px rgba(15, 118, 110, .24);
    }
    nav a {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 8px;
      padding: 10px 12px;
      margin: 4px 0;
      border-radius: 8px;
      color: var(--muted);
      text-decoration: none;
      font-size: 14px;
    }
    nav a.active,
    nav a:hover {
      color: var(--ink);
      background: var(--soft);
    }
    .section-nav a {
      padding: 8px 10px;
      margin: 3px 0;
      font-size: 12px;
      line-height: 1.3;
    }
    .progress-wrap {
      margin: 12px 0;
      padding: 10px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }
    .progress-label {
      display: flex;
      justify-content: space-between;
      font-size: 13px;
      color: var(--muted);
      margin-bottom: 8px;
    }
    .progress-bar {
      height: 8px;
      border-radius: 999px;
      background: #dfe8e3;
      overflow: hidden;
    }
    .progress-bar span {
      display: block;
      height: 100%;
      width: 0%;
      background: var(--teal);
      transition: width .2s ease;
    }
    main { grid-column: 2; min-width: 0; }
    .hero {
      min-height: 88vh;
      display: grid;
      align-items: center;
      padding: 54px clamp(24px, 6vw, 86px) 36px;
      color: white;
      background:
        linear-gradient(90deg, rgba(9, 37, 34, .92) 0%, rgba(9, 37, 34, .76) 42%, rgba(9, 37, 34, .38) 100%),
        url("https://images.unsplash.com/photo-1518005020951-eccb494ad742?auto=format&fit=crop&w=1800&q=80") center/cover;
    }
    .hero-inner { max-width: 900px; }
    .eyebrow {
      color: #bfe8df;
      font-weight: 700;
      letter-spacing: .08em;
      text-transform: uppercase;
      font-size: 13px;
    }
    h1 {
      max-width: 820px;
      margin: 14px 0 18px;
      font-size: clamp(42px, 6vw, 76px);
      line-height: 1.02;
      letter-spacing: 0;
    }
    .hero p {
      max-width: 720px;
      color: #e8f4ef;
      font-size: clamp(18px, 2vw, 22px);
      margin: 0 0 28px;
    }
    .hero-actions {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
    }
    .btn {
      min-height: 44px;
      border: 1px solid transparent;
      border-radius: 8px;
      padding: 10px 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      cursor: pointer;
      text-decoration: none;
      font-weight: 750;
      transition: transform .14s ease, box-shadow .14s ease, background .14s ease;
    }
    .btn:hover { transform: translateY(-1px); }
    .btn.primary {
      color: white;
      background: var(--teal);
      box-shadow: 0 12px 26px rgba(15, 118, 110, .24);
    }
    .btn.secondary {
      color: var(--ink);
      background: #fff;
    }
    .btn.ghost {
      color: var(--teal-dark);
      background: var(--soft);
      border-color: var(--line);
    }
    section {
      padding: 64px clamp(22px, 5vw, 76px);
      border-bottom: 1px solid var(--line);
    }
    .section-head {
      max-width: 860px;
      margin-bottom: 28px;
    }
    h2 {
      margin: 0 0 10px;
      font-size: clamp(28px, 4vw, 44px);
      line-height: 1.12;
      letter-spacing: 0;
    }
    h3 {
      margin: 0 0 10px;
      font-size: 22px;
      letter-spacing: 0;
    }
    .lead {
      color: var(--muted);
      font-size: 18px;
      margin: 0;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(12, 1fr);
      gap: 18px;
    }
    .card {
      grid-column: span 4;
      padding: 22px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: var(--panel);
      box-shadow: 0 8px 30px rgba(22, 32, 29, .05);
    }
    .card.wide { grid-column: span 8; }
    .card.full { grid-column: 1 / -1; }
    .tag {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      min-height: 26px;
      padding: 2px 9px;
      border-radius: 999px;
      background: var(--soft);
      color: var(--teal-dark);
      font-size: 12px;
      font-weight: 800;
    }
    .plain-list {
      padding-left: 20px;
      margin: 12px 0 0;
    }
    .plain-list li { margin: 8px 0; }
    .steps {
      display: grid;
      gap: 14px;
    }
    .step {
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      overflow: hidden;
    }
    .step summary {
      list-style: none;
      padding: 18px 20px;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 18px;
      font-weight: 800;
    }
    .step summary::-webkit-details-marker { display: none; }
    .step-body {
      padding: 0 20px 20px;
      color: var(--muted);
    }
    .copybox {
      margin: 14px 0;
      border-radius: 8px;
      overflow: hidden;
      border: 1px solid #27372f;
      background: var(--code);
      box-shadow: var(--shadow);
    }
    .copybar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 12px;
      padding: 10px 12px;
      color: #c1d0c8;
      background: var(--code-2);
      font-size: 13px;
    }
    .copybar button {
      color: white;
      background: #2f7d70;
      border: 0;
      border-radius: 8px;
      padding: 7px 10px;
      cursor: pointer;
      font-size: 13px;
      font-weight: 750;
    }
    pre {
      margin: 0;
      padding: 18px;
      overflow: auto;
      color: #e5f3ec;
      font: 14px/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
      white-space: pre-wrap;
    }
    .note {
      border-left: 4px solid var(--gold);
      background: #fff8e7;
      padding: 14px 16px;
      border-radius: 0 8px 8px 0;
      color: #5f431b;
    }
    .danger {
      border-left-color: var(--rose);
      background: #fff1f4;
      color: #6f2138;
    }
    .choice-guide {
      display: grid;
      gap: 12px;
      margin: 16px 0;
    }
    .choice {
      border: 1px solid var(--line);
      border-radius: 8px;
      padding: 14px;
      background: #fff;
    }
    .choice.recommended {
      border-color: rgba(15, 118, 110, .45);
      background: var(--soft);
    }
    .choice strong {
      display: block;
      margin-bottom: 4px;
    }
    .billing-note {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin: 16px 0;
    }
    .billing-note div {
      border: 1px solid var(--line);
      border-radius: 8px;
      padding: 13px;
      background: #fff;
    }
    .tabs {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      margin: 0 0 18px;
    }
    .tab {
      border: 1px solid var(--line);
      background: #fff;
      color: var(--muted);
      padding: 10px 13px;
      border-radius: 8px;
      cursor: pointer;
      font-weight: 800;
    }
    .tab.active {
      color: white;
      border-color: var(--teal);
      background: var(--teal);
    }
    .tab-panel { display: none; }
    .tab-panel.active { display: block; }
    .terminal {
      border-radius: 8px;
      background: #0f1714;
      color: #e7f1eb;
      border: 1px solid #27372f;
      overflow: hidden;
      box-shadow: var(--shadow);
    }
    .traffic {
      display: flex;
      gap: 8px;
      padding: 12px;
      background: #1b2924;
    }
    .dot { width: 12px; height: 12px; border-radius: 50%; }
    .red { background: #ff5f57; }
    .yellow { background: #ffbd2e; }
    .green { background: #28c840; }
    .term-body {
      min-height: 260px;
      padding: 18px;
      font: 14px/1.6 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    }
    .prompt { color: #8be9d4; }
    .muted-term { color: #89a59b; }
    .type-target::after {
      content: "";
      display: inline-block;
      width: 8px;
      height: 18px;
      margin-left: 2px;
      background: #bfe8df;
      vertical-align: text-bottom;
      animation: blink 1s step-end infinite;
    }
    @keyframes blink { 50% { opacity: 0; } }
    .checklist {
      display: grid;
      gap: 10px;
    }
    .check {
      display: flex;
      gap: 10px;
      align-items: flex-start;
      padding: 12px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }
    .check input {
      width: 20px;
      height: 20px;
      margin-top: 3px;
      accent-color: var(--teal);
    }
    .dashboard {
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      overflow: hidden;
      box-shadow: var(--shadow);
    }
    .dash-top {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 12px 16px;
      border-bottom: 1px solid var(--line);
      background: #f3f8f5;
      font-weight: 800;
    }
    .dash-body {
      display: grid;
      grid-template-columns: 180px 1fr;
      min-height: 420px;
    }
    .dash-menu {
      border-right: 1px solid var(--line);
      padding: 12px;
      background: #fbfdfb;
    }
    .dash-menu button {
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin: 4px 0;
      padding: 10px 12px;
      border: 0;
      border-radius: 8px;
      background: transparent;
      color: var(--muted);
      text-align: left;
      cursor: pointer;
      font-weight: 750;
    }
    .dash-menu button.active,
    .dash-menu button:hover {
      background: var(--soft);
      color: var(--ink);
    }
    .dash-screen { padding: 18px; }
    .metric-row {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin-bottom: 14px;
    }
    .metric {
      border: 1px solid var(--line);
      border-radius: 8px;
      padding: 14px;
      background: #fff;
    }
    .metric strong {
      display: block;
      font-size: 24px;
      line-height: 1.2;
    }
    .fake-table {
      border: 1px solid var(--line);
      border-radius: 8px;
      overflow: hidden;
    }
    .fake-row {
      display: grid;
      grid-template-columns: 1.1fr .8fr .8fr;
      gap: 10px;
      padding: 11px 12px;
      border-bottom: 1px solid var(--line);
      color: var(--muted);
      font-size: 14px;
    }
    .fake-row:first-child {
      color: var(--ink);
      font-weight: 800;
      background: #f7faf8;
    }
    .fake-row:last-child { border-bottom: 0; }
    .quiz {
      display: grid;
      gap: 10px;
      margin-top: 14px;
    }
    .quiz button {
      text-align: left;
      padding: 12px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      cursor: pointer;
    }
    .quiz button.correct { border-color: var(--teal); background: var(--soft); }
    .quiz button.wrong { border-color: var(--rose); background: #fff1f4; }
    .result {
      min-height: 26px;
      margin-top: 8px;
      color: var(--muted);
      font-weight: 750;
    }
    .timeline {
      display: grid;
      gap: 12px;
    }
    .timeline-item {
      display: grid;
      grid-template-columns: 36px 1fr;
      gap: 12px;
      align-items: start;
    }
    .screenshot-strip {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 14px;
      margin: 18px 0;
    }
    .screenshot-card {
      border: 1px solid var(--line);
      border-radius: 8px;
      overflow: hidden;
      background: #fff;
      box-shadow: 0 12px 32px rgba(22, 32, 29, .08);
    }
    .shot-bar {
      display: flex;
      align-items: center;
      gap: 6px;
      padding: 9px 10px;
      border-bottom: 1px solid var(--line);
      background: #f3f8f5;
      font-size: 12px;
      color: var(--muted);
    }
    .shot-dot {
      width: 9px;
      height: 9px;
      border-radius: 50%;
      background: #8fb3a9;
    }
    .shot-body {
      min-height: 190px;
      padding: 14px;
      background: #fbfdfb;
    }
    .shot-title {
      font-weight: 850;
      margin-bottom: 10px;
    }
    .shot-caption {
      margin: 10px 0 0;
      color: var(--muted);
      font-size: 13px;
    }
    .mini-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 8px;
    }
    .mini-block {
      min-height: 52px;
      border: 1px solid var(--line);
      border-radius: 8px;
      padding: 8px;
      background: #fff;
      font-size: 12px;
      color: var(--muted);
    }
    .mini-line {
      height: 8px;
      margin: 8px 0;
      border-radius: 999px;
      background: #dce8e3;
    }
    .dashboard-reference {
      margin: 18px 0 22px;
      border: 1px solid rgba(214, 223, 218, .42);
      border-radius: 8px;
      overflow: hidden;
      background: #062521;
      box-shadow: var(--shadow);
    }
    .dashboard-reference img {
      display: block;
      width: 100%;
      height: auto;
    }
    .command-explain {
      display: grid;
      gap: 10px;
      margin-top: 16px;
    }
    .command-row {
      display: grid;
      grid-template-columns: minmax(160px, .6fr) 1fr;
      gap: 12px;
      align-items: start;
      padding: 12px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }
    .num {
      width: 32px;
      height: 32px;
      display: grid;
      place-items: center;
      border-radius: 8px;
      background: var(--teal);
      color: white;
      font-weight: 900;
    }
    footer {
      padding: 36px clamp(22px, 5vw, 76px);
      color: var(--muted);
      background: #fff;
    }
    .mobile-only { display: none; }

    @media (max-width: 1200px) {
      .local-panel {
        display: none;
      }
    }
    @media (max-width: 980px) {
      .shell { display: flex; flex-direction: column; }
      main { order: 2; }
      .menu-toggle { display: grid; place-items: center; }
      .global-menu {
        position: fixed;
        z-index: 50;
        top: 0;
        left: 0;
        width: min(82vw, 300px);
        height: 100vh;
        transform: translateX(-105%);
        transition: transform .18s ease;
        border-right: 1px solid var(--line);
        border-bottom: 0;
      }
      body.menu-open .global-menu { transform: translateX(0); }
      .tutorial-nav {
        display: block;
      }
      .card, .card.wide { grid-column: 1 / -1; }
      .dash-body { grid-template-columns: 1fr; }
      .dash-menu {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        border-right: 0;
        border-bottom: 1px solid var(--line);
      }
      .metric-row { grid-template-columns: 1fr; }
      .billing-note { grid-template-columns: 1fr; }
      .screenshot-strip { grid-template-columns: 1fr; }
      .command-row { grid-template-columns: 1fr; }
    }
    @media (max-width: 620px) {
      .hero { min-height: 82vh; }
      .hero-actions .btn { width: 100%; }
      section { padding-top: 44px; padding-bottom: 44px; }
      .dash-menu { grid-template-columns: 1fr 1fr; }
      .fake-row { grid-template-columns: 1fr; }
      .mobile-only { display: inline; }
    }