/* ============================================
       LINEAR DESIGN SYSTEM
       Based on DESIGN.md specifications
       ============================================ */
    :root {
      /* Background Surfaces */
      --bg-marketing: #08090a;
      --bg-panel: #0f1011;
      --bg-surface: #191a1b;
      --bg-elevated: #28282c;
      
      /* Text Colors */
      --text-primary: #f7f8f8;
      --text-secondary: #d0d6e0;
      --text-tertiary: #8a8f98;
      --text-muted: #62666d;
      
      /* Brand & Accent (Linear's signature indigo-violet) */
      --brand-indigo: #5e6ad2;
      --accent-violet: #7170ff;
      --accent-hover: #828fff;
      --accent-lavender: #7a7fad;
      
      /* Borders - semi-transparent white */
      --border-subtle: rgba(255,255,255,0.05);
      --border-standard: rgba(255,255,255,0.08);
      --border-light: rgba(255,255,255,0.12);
      
      /* Button backgrounds - near-zero opacity */
      --btn-ghost: rgba(255,255,255,0.02);
      --btn-subtle: rgba(255,255,255,0.04);
      --btn-surface: rgba(255,255,255,0.06);
      
      /* Shadows */
      --shadow-surface: rgba(0,0,0,0.2) 0px 0px 0px 1px;
      --shadow-elevated: rgba(0,0,0,0.4) 0px 2px 4px;
      --shadow-focus: rgba(0,0,0,0.1) 0px 4px 12px;
      --shadow-dialog: rgba(0,0,0,0) 0px 8px 2px, rgba(0,0,0,0.01) 0px 5px 2px, rgba(0,0,0,0.04) 0px 3px 2px, rgba(0,0,0,0.07) 0px 1px 1px, rgba(0,0,0,0.08) 0px 0px 1px;
      
      /* Typography */
      --font-primary: 'Inter', -apple-system, system-ui, 'Segoe UI', Roboto, sans-serif;
      --font-mono: 'ui-monospace', 'SF Mono', 'Menlo', monospace;
      
      /* Spacing */
      --radius-micro: 2px;
      --radius-standard: 4px;
      --radius-comfortable: 6px;
      --radius-card: 8px;
      --radius-panel: 12px;
      --radius-pill: 9999px;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
      font-feature-settings: "cv01", "ss03";
    }

    body {
      font-family: var(--font-primary);
      background: var(--bg-marketing);
      color: var(--text-primary);
      overflow-x: hidden;
      min-height: 100vh;
      font-feature-settings: "cv01", "ss03";
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    /* Subtle background texture */
    body::before {
      content: '';
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: 
        radial-gradient(circle at 20% 30%, rgba(94, 106, 210, 0.06) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(113, 112, 255, 0.04) 0%, transparent 40%);
      pointer-events: none;
      z-index: -1;
    }

    /* Sections */
    .section {
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      padding: 4rem 1.5rem;
      position: relative;
    }

    .section-content {
      max-width: 1100px;
      width: 100%;
      text-align: center;
      animation: fadeIn 0.6s ease-out;
    }

    .section-content-narrow {
      max-width: 680px;
    }

    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }

    /* Typography - Linear Style */
    h1 {
      font-family: var(--font-primary);
      font-size: clamp(2.5rem, 7vw, 3.5rem);
      font-weight: 510;
      line-height: 1.05;
      letter-spacing: -0.8px;
      margin-bottom: 1rem;
      color: var(--text-primary);
    }

    h2 {
      font-family: var(--font-primary);
      font-size: clamp(1.5rem, 4vw, 2rem);
      font-weight: 400;
      line-height: 1.2;
      margin-bottom: 0.5rem;
      letter-spacing: -0.4px;
      color: var(--text-primary);
    }

    h3 {
      font-family: var(--font-primary);
      font-size: clamp(1rem, 3vw, 1.25rem);
      font-weight: 590;
      color: var(--text-secondary);
      margin-bottom: 1rem;
      letter-spacing: -0.2px;
    }

    p {
      font-size: clamp(0.95rem, 2vw, 1.05rem);
      font-weight: 400;
      color: var(--text-secondary);
      line-height: 1.6;
      max-width: 500px;
      margin: 0 auto;
    }

    .subtitle {
      font-size: clamp(1rem, 2.5vw, 1.15rem);
      font-weight: 400;
      color: var(--text-tertiary);
      margin-bottom: 1.5rem;
    }

    /* Cover Section */
    .cover-icon {
      width: 72px;
      height: 72px;
      background: var(--brand-indigo);
      border-radius: var(--radius-panel);
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 1.75rem;
      font-size: 2rem;
      box-shadow: 0 8px 24px rgba(94, 106, 210, 0.3);
    }

    /* Section Number - Linear Style */
    .section-number {
      font-family: var(--font-primary);
      font-size: 0.75rem;
      font-weight: 510;
      color: var(--text-muted);
      letter-spacing: 0.15em;
      text-transform: uppercase;
      margin-bottom: 0.75rem;
    }

    /* Cards Grid - 5 columns */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      gap: 1rem;
      margin-top: 2rem;
      width: 100%;
    }

    .card {
      background: var(--btn-ghost);
      border: 1px solid var(--border-standard);
      border-radius: var(--radius-card);
      padding: 1.5rem 1.25rem;
      text-align: left;
      transition: all 0.25s ease;
      display: flex;
      flex-direction: column;
    }

    .card:hover {
      background: var(--btn-subtle);
      border-color: var(--border-light);
      transform: translateY(-2px);
    }

    .card-icon {
      width: 40px;
      height: 40px;
      background: var(--btn-subtle);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-standard);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.25rem;
      margin-bottom: 1rem;
    }

    .card h4 {
      font-family: var(--font-primary);
      font-size: 1rem;
      font-weight: 590;
      margin-bottom: 0.5rem;
      color: var(--text-primary);
      letter-spacing: -0.1px;
    }

    .card ul {
      list-style: none;
      padding: 0;
      margin: 0;
      flex-grow: 1;
    }

    .card li {
      color: var(--text-tertiary);
      font-size: 0.8rem;
      padding: 0.35rem 0;
      padding-left: 1rem;
      position: relative;
      line-height: 1.4;
    }

    .card li::before {
      content: '→';
      position: absolute;
      left: 0;
      color: var(--accent-violet);
      font-size: 0.7rem;
    }

    /* Cycle Diagram - Linear Style */
    .cycle-container {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      margin: 2rem 0;
      flex-wrap: wrap;
    }

    .cycle-step {
      background: var(--btn-ghost);
      border: 1px solid var(--border-standard);
      color: var(--text-secondary);
      padding: 0.6rem 1.2rem;
      border-radius: var(--radius-comfortable);
      font-weight: 510;
      font-size: 0.85rem;
      transition: all 0.25s ease;
    }

    .cycle-step:hover {
      background: var(--btn-subtle);
      border-color: var(--border-light);
      color: var(--text-primary);
    }

    .cycle-arrow {
      color: var(--accent-violet);
      font-size: 1.2rem;
    }

    /* Navigation - Fixed bottom */
    .nav-buttons {
      position: fixed;
      bottom: 1.5rem;
      left: 50%;
      transform: translateX(-50%);
      display: flex;
      gap: 0.75rem;
      z-index: 100;
    }

    .nav-btn {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      border: 1px solid var(--border-standard);
      background: var(--btn-subtle);
      color: var(--text-secondary);
      font-size: 1.2rem;
      cursor: pointer;
      transition: all 0.2s ease;
      display: flex;
      align-items: center;
      justify-content: center;
      backdrop-filter: blur(8px);
    }

    .nav-btn:hover {
      background: var(--btn-surface);
      border-color: var(--border-light);
      color: var(--text-primary);
    }

    .nav-btn:disabled {
      opacity: 0.25;
      cursor: not-allowed;
    }

    .nav-btn:disabled:hover {
      background: var(--btn-subtle);
      border-color: var(--border-standard);
      color: var(--text-secondary);
    }

    /* Progress Dots - Right side */
    .progress-dots {
      position: fixed;
      right: 1.25rem;
      top: 50%;
      transform: translateY(-50%);
      display: flex;
      flex-direction: column;
      gap: 0.6rem;
      z-index: 100;
    }

    .dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: var(--border-subtle);
      cursor: pointer;
      transition: all 0.25s ease;
    }

    .dot.active {
      background: var(--accent-violet);
      box-shadow: 0 0 8px rgba(113, 112, 255, 0.4);
    }

    .dot:hover {
      background: var(--accent-violet);
    }

    /* CTA Button - Linear Primary Brand Style */
    .cta-btn {
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      background: var(--brand-indigo);
      color: #ffffff;
      padding: 0.75rem 1.5rem;
      border-radius: var(--radius-comfortable);
      font-weight: 510;
      font-size: 0.95rem;
      text-decoration: none;
      margin-top: 1.75rem;
      transition: all 0.2s ease;
      border: none;
      cursor: pointer;
    }

    .cta-btn:hover {
      background: var(--accent-hover);
      transform: translateY(-1px);
      box-shadow: 0 4px 12px rgba(94, 106, 210, 0.35);
    }

    /* Ghost Button variant */
    .cta-btn-ghost {
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      background: var(--btn-ghost);
      color: var(--text-secondary);
      padding: 0.75rem 1.5rem;
      border-radius: var(--radius-comfortable);
      font-weight: 510;
      font-size: 0.95rem;
      text-decoration: none;
      margin-top: 1rem;
      margin-left: 0.75rem;
      transition: all 0.2s ease;
      border: 1px solid var(--border-standard);
      cursor: pointer;
    }

    .cta-btn-ghost:hover {
      background: var(--btn-subtle);
      border-color: var(--border-light);
      color: var(--text-primary);
    }

    /* Detail Cards */
    .detail-card {
      background: var(--btn-ghost);
      border: 1px solid var(--border-standard);
      border-radius: var(--radius-card);
      padding: 1.5rem;
      text-align: left;
      max-width: 450px;
      margin: 1.5rem auto 0;
    }

    .detail-card-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1rem;
      max-width: 700px;
      margin: 1.5rem auto 0;
    }

    .stat-card {
      background: var(--btn-ghost);
      border: 1px solid var(--border-standard);
      border-radius: var(--radius-card);
      padding: 1.25rem;
      text-align: center;
    }

    .stat-number {
      color: var(--text-primary);
      font-weight: 590;
      font-size: 2rem;
      font-family: var(--font-primary);
      letter-spacing: -0.5px;
    }

    .stat-label {
      color: var(--text-tertiary);
      font-size: 0.8rem;
      margin-top: 0.25rem;
    }

    .stat-icon {
      font-size: 2rem;
      margin-bottom: 0.5rem;
    }

    /* Detail card internal items */
    .detail-item {
      margin-bottom: 1rem;
    }

    .detail-item:last-child {
      margin-bottom: 0;
    }

    .detail-item-title {
      font-weight: 590;
      font-size: 0.9rem;
      color: var(--accent-violet);
      margin-bottom: 0.25rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .detail-item p {
      font-size: 0.85rem;
      color: var(--text-tertiary);
      max-width: 100%;
      margin: 0;
      line-height: 1.5;
    }

    /* Footer CTA */
    .footer-cta {
      background: linear-gradient(180deg, transparent 0%, rgba(94, 106, 210, 0.05) 100%);
      border-top: 1px solid var(--border-subtle);
    }

    /* Italic small text */
    .italic-note {
      font-size: 0.8rem;
      font-style: italic;
      color: var(--text-muted);
      margin-top: 1rem;
      line-height: 1.5;
    }

    /* ============================================
       RESPONSIVE DESIGN
       ============================================ */
    @media (max-width: 1024px) {
      .cards-grid {
        grid-template-columns: repeat(3, 1fr);
      }
    }

    @media (max-width: 768px) {
      /* Hide progress dots on mobile */
      .progress-dots {
        display: none;
      }

      /* Navigation buttons */
      .nav-buttons {
        bottom: 1rem;
        gap: 0.75rem;
      }

      .nav-btn {
        width: 52px;
        height: 52px;
        font-size: 1.3rem;
      }

      /* Sections */
      .section {
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding: 3rem 1.25rem 5rem 1.25rem;
        scroll-margin-top: 0;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
      }

      .section-content {
        max-width: 100%;
        width: 100%;
        text-align: center;
        animation: fadeIn 0.6s ease-out;
        flex-shrink: 0;
      }

      .section-content-narrow {
        max-width: 100%;
      }

      /* Spacing */
      .section-content > * + * {
        margin-top: 0.5rem;
      }

      /* Typography */
      .section-number {
        margin-bottom: 0.5rem;
        font-size: 0.7rem;
      }

      h1 {
        font-size: clamp(2rem, 8vw, 2.5rem);
        letter-spacing: -0.6px;
      }

      .subtitle {
        margin-bottom: 1rem;
        font-size: clamp(1rem, 3.5vw, 1.1rem);
      }

      h2 {
        font-size: clamp(1.4rem, 5vw, 1.7rem);
        letter-spacing: -0.3px;
      }

      h3 {
        font-size: clamp(1rem, 3.5vw, 1.1rem);
      }

      p {
        font-size: clamp(0.95rem, 3vw, 1rem);
        max-width: 100%;
      }

      /* Cover icon */
      .cover-icon {
        width: 64px;
        height: 64px;
        font-size: 1.75rem;
        margin-bottom: 1.25rem;
        border-radius: var(--radius-panel);
      }

      /* CTA buttons */
      .cta-btn {
        margin-top: 1.25rem;
        padding: 0.7rem 1.25rem;
        font-size: 0.9rem;
        min-height: 48px;
      }

      .cta-btn-ghost {
        margin-top: 0.75rem;
        margin-left: 0.5rem;
        padding: 0.7rem 1.25rem;
        font-size: 0.9rem;
      }

      /* Cycle diagram */
      .cycle-container {
        margin: 1rem 0;
        gap: 0.35rem;
      }

      .cycle-step {
        padding: 0.55rem 0.9rem;
        font-size: 0.8rem;
        border-radius: var(--radius-comfortable);
      }

      .cycle-arrow {
        font-size: 1rem;
      }

      /* Cards */
      .card {
        padding: 1.1rem;
        border-radius: var(--radius-card);
      }

      .card-icon {
        width: 36px;
        height: 36px;
        font-size: 1.1rem;
        margin-bottom: 0.75rem;
        border-radius: var(--radius-standard);
      }

      .card h4 {
        font-size: 0.95rem;
        margin-bottom: 0.4rem;
      }

      .card li {
        font-size: 0.78rem;
        padding: 0.3rem 0;
        padding-left: 0.9rem;
      }

      .card li::before {
        font-size: 0.65rem;
      }

      /* Detail cards */
      .detail-card {
        padding: 1.1rem;
        margin-top: 1rem;
        border-radius: var(--radius-card);
        text-align: left;
      }

      .detail-card p {
        font-size: 0.85rem;
      }

      .detail-card-grid {
        margin-top: 1rem;
        gap: 0.75rem;
      }

      .stat-card {
        padding: 1rem;
        border-radius: var(--radius-card);
      }

      .stat-number {
        font-size: 1.6rem;
      }

      .stat-label {
        font-size: 0.75rem;
      }

      .stat-icon {
        font-size: 1.6rem;
      }

      .detail-item {
        margin-bottom: 0.75rem;
      }

      .detail-item-title {
        font-size: 0.85rem;
      }

      .detail-item p {
        font-size: 0.8rem;
      }

      /* Section 3: 5 Pillars - vertical scroll */
      #section-2 {
        padding: 3rem 1.25rem 5rem 1.25rem;
        min-height: 100vh;
      }

      #section-2 .section-content {
        display: flex;
        flex-direction: column;
        height: 100%;
      }

      #section-2 > .section-content > p {
        margin-bottom: 0.75rem;
      }

      #section-2 .cards-grid {
        display: flex;
        flex-direction: column;
        gap: 0.75rem;
        overflow-y: auto;
        scrollbar-width: none;
        -ms-overflow-style: none;
        scroll-snap-type: y mandatory;
        padding-bottom: 1rem;
        flex-grow: 1;
      }

      #section-2 .cards-grid::-webkit-scrollbar {
        display: none;
      }

      #section-2 .card {
        flex-shrink: 0;
        scroll-snap-align: center;
        min-height: calc(100vh - 280px);
        display: flex;
        flex-direction: column;
        justify-content: center;
        border-radius: var(--radius-card);
        padding: 1.25rem;
      }

      #section-2 .card h4 {
        font-size: 1.1rem;
        margin-bottom: 0.5rem;
      }

      #section-2 .card li {
        font-size: 0.9rem;
        padding: 0.35rem 0;
        padding-left: 1rem;
      }

      #section-2 .card ul {
        margin-top: 0.25rem;
      }

      /* Italic note */
      .italic-note {
        font-size: 0.75rem;
        margin-top: 0.75rem;
      }
    }