/* ========================================
       CSS Custom Properties
       ======================================== */
    :root {
      --color-aws-dark: #232F3E;
      --color-aws-orange: #dc7600;
      --color-aws-orange-original: #FF9900;
      --color-text-primary: #374151;
      --color-text-secondary: #6B7280;
      --color-text-white: #FFFFFF;
      --color-bg-light: #F9FAFB;
      --color-bg-white: #FFFFFF;
      --color-border-light: #E5E7EB;
      --color-success: #10B981;
      --color-warning: #F59E0B;
      --color-error: #EF4444;
      --color-info: #3B82F6;
      --color-category-networking: #74b9ff;
      --spacing-sm: 10px;
      --spacing-md: 15px;
      --spacing-base: 20px;
      --spacing-lg: 25px;
      --spacing-xl: 30px;
      --spacing-2xl: 40px;
      --spacing-3xl: 60px;
      --radius-sm: 6px;
      --radius-md: 8px;
      --radius-base: 10px;
      --radius-lg: 15px;
      --radius-xl: 20px;
      --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
      --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
      --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.15);
      --transition-base: 0.3s ease;
    }

    /* ========================================
       Base Styles
       ======================================== */
    *,
    *::before,
    *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Segoe UI", sans-serif;
      font-size: 20px;
      line-height: 1.7;
      color: var(--color-text-primary);
      background-color: var(--color-bg-light);
    }

    /* ========================================
       Container
       ======================================== */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: var(--spacing-xl);
    }

    /* ========================================
       Hero Section
       ======================================== */
    .hero {
      background: linear-gradient(135deg, var(--color-aws-dark) 0%, #374151 60%, #1a2332 100%);
      color: var(--color-text-white);
      padding: var(--spacing-3xl) var(--spacing-xl);
      text-align: center;
      position: relative;
      overflow: hidden;
    }

    .hero::before {
      content: "";
      position: absolute;
      top: -50%;
      left: -50%;
      width: 200%;
      height: 200%;
      background: radial-gradient(circle at 30% 40%, rgba(255, 153, 0, 0.08) 0%, transparent 50%),
                  radial-gradient(circle at 70% 60%, rgba(59, 130, 246, 0.06) 0%, transparent 50%);
      pointer-events: none;
    }

    .hero-content {
      position: relative;
      max-width: 900px;
      margin: 0 auto;
    }

    .hero-badge {
      display: inline-block;
      background: rgba(255, 153, 0, 0.2);
      color: var(--color-aws-orange-original);
      padding: 8px 24px;
      border-radius: 30px;
      font-size: 20px;
      font-weight: 600;
      margin-bottom: var(--spacing-base);
      border: 1px solid rgba(255, 153, 0, 0.3);
    }

    .hero h1 {
      font-size: 40px;
      font-weight: 700;
      margin-bottom: var(--spacing-md);
      line-height: 1.3;
    }

    .hero-subtitle {
      font-size: 22px;
      color: rgba(255, 255, 255, 0.8);
      margin-bottom: var(--spacing-2xl);
    }

    /* ========================================
       Conclusion First Cards
       ======================================== */
    .conclusion-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-base);
      margin-top: var(--spacing-xl);
    }

    .conclusion-card {
      background: rgba(255, 255, 255, 0.08);
      border: 1px solid rgba(255, 255, 255, 0.15);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      text-align: left;
      backdrop-filter: blur(10px);
      transition: transform var(--transition-base), background var(--transition-base);
    }

    .conclusion-card:hover {
      transform: translateY(-3px);
      background: rgba(255, 255, 255, 0.12);
    }

    .conclusion-icon {
      font-size: 32px;
      margin-bottom: var(--spacing-sm);
    }

    .conclusion-card h3 {
      font-size: 22px;
      color: var(--color-aws-orange-original);
      margin-bottom: 8px;
    }

    .conclusion-card p {
      font-size: 20px;
      color: rgba(255, 255, 255, 0.85);
      line-height: 1.6;
    }

    /* ========================================
       Section Common
       ======================================== */
    .section {
      background: var(--color-bg-white);
      border-radius: var(--radius-xl);
      padding: var(--spacing-2xl);
      margin: var(--spacing-xl) 0;
      box-shadow: var(--shadow-md);
    }

    .section-title {
      font-size: 30px;
      font-weight: 700;
      color: var(--color-aws-dark);
      margin-bottom: var(--spacing-lg);
      padding-bottom: var(--spacing-md);
      border-bottom: 3px solid var(--color-aws-orange-original);
      display: flex;
      align-items: center;
      gap: var(--spacing-sm);
    }

    .section-title-icon {
      font-size: 32px;
    }

    /* ========================================
       Analogy Section
       ======================================== */
    .analogy-intro {
      background: linear-gradient(135deg, #FFF7ED, #FFFBF5);
      border: 2px solid #FDBA74;
      border-radius: var(--radius-lg);
      padding: var(--spacing-xl);
      margin-bottom: var(--spacing-xl);
      text-align: center;
    }

    .analogy-intro h3 {
      font-size: 26px;
      color: var(--color-aws-dark);
      margin-bottom: var(--spacing-sm);
    }

    .analogy-intro p {
      font-size: 22px;
      color: var(--color-text-primary);
    }

    .analogy-mapping {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-base);
      margin-top: var(--spacing-xl);
    }

    .analogy-card {
      background: var(--color-bg-white);
      border: 2px solid var(--color-border-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      transition: transform var(--transition-base), box-shadow var(--transition-base);
    }

    .analogy-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
    }

    .analogy-card-header {
      display: flex;
      align-items: center;
      gap: var(--spacing-sm);
      margin-bottom: var(--spacing-md);
    }

    .analogy-emoji {
      font-size: 36px;
      flex-shrink: 0;
    }

    .analogy-card h4 {
      font-size: 22px;
      color: var(--color-aws-dark);
    }

    .analogy-real {
      background: #EEF2FF;
      border-radius: var(--radius-md);
      padding: var(--spacing-md);
      margin-bottom: var(--spacing-sm);
    }

    .analogy-real-label {
      font-size: 20px;
      font-weight: 700;
      color: #4338CA;
      margin-bottom: 4px;
    }

    .analogy-aws {
      background: #FFF7ED;
      border-radius: var(--radius-md);
      padding: var(--spacing-md);
    }

    .analogy-aws-label {
      font-size: 20px;
      font-weight: 700;
      color: #B45309;
      margin-bottom: 4px;
    }

    /* ========================================
       Mapping Table
       ======================================== */
    .mapping-table-wrapper {
      overflow-x: auto;
      margin-top: var(--spacing-xl);
    }

    .mapping-table {
      width: 100%;
      border-collapse: collapse;
      font-size: 20px;
    }

    .mapping-table thead th {
      background: var(--color-aws-dark);
      color: var(--color-text-white);
      padding: var(--spacing-md) var(--spacing-base);
      text-align: left;
      font-weight: 700;
      font-size: 20px;
    }

    .mapping-table thead th:first-child {
      border-radius: var(--radius-md) 0 0 0;
    }

    .mapping-table thead th:last-child {
      border-radius: 0 var(--radius-md) 0 0;
    }

    .mapping-table tbody td {
      padding: var(--spacing-md) var(--spacing-base);
      border-bottom: 1px solid var(--color-border-light);
      vertical-align: top;
    }

    .mapping-table tbody tr:nth-child(even) {
      background: var(--color-bg-light);
    }

    .mapping-table tbody tr:hover {
      background: #FFF7ED;
    }

    /* ========================================
       SVG Diagram Container
       ======================================== */
    .diagram-container {
      background: #F8FAFC;
      border-radius: var(--radius-lg);
      padding: var(--spacing-base);
      margin: var(--spacing-xl) 0;
      overflow-x: auto;
    }

    .diagram-container svg {
      display: block;
      max-width: 100%;
      height: auto;
      margin: 0 auto;
    }

    /* ========================================
       Comparison Section
       ======================================== */
    .comparison-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-xl);
    }

    .comparison-card {
      border-radius: var(--radius-lg);
      padding: var(--spacing-xl);
      position: relative;
    }

    .comparison-card--without {
      background: linear-gradient(135deg, #FEF2F2, #FFF5F5);
      border: 2px solid #FECACA;
    }

    .comparison-card--with {
      background: linear-gradient(135deg, #ECFDF5, #F0FDF9);
      border: 2px solid #A7F3D0;
    }

    .comparison-card h3 {
      font-size: 24px;
      margin-bottom: var(--spacing-md);
      display: flex;
      align-items: center;
      gap: var(--spacing-sm);
    }

    .comparison-card--without h3 {
      color: #B91C1C;
    }

    .comparison-card--with h3 {
      color: #047857;
    }

    .comparison-list {
      list-style: none;
      padding: 0;
    }

    .comparison-list li {
      padding: 8px 0;
      font-size: 20px;
      display: flex;
      align-items: flex-start;
      gap: 8px;
    }

    .comparison-list li::before {
      flex-shrink: 0;
      font-size: 20px;
    }

    .comparison-card--without .comparison-list li::before {
      content: "✗";
      color: var(--color-error);
      font-weight: 700;
    }

    .comparison-card--with .comparison-list li::before {
      content: "✓";
      color: var(--color-success);
      font-weight: 700;
    }

    /* ========================================
       Step Flow
       ======================================== */
    .step-flow {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-xl);
      margin: var(--spacing-xl) 0;
    }

    .step-card {
      background: var(--color-bg-white);
      border: 2px solid var(--color-border-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      position: relative;
      transition: transform var(--transition-base), box-shadow var(--transition-base);
    }

    .step-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
    }

    .step-number {
      position: absolute;
      top: -16px;
      left: var(--spacing-lg);
      width: 40px;
      height: 40px;
      background: var(--color-info);
      color: var(--color-text-white);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 20px;
      font-weight: 700;
    }

    .step-card h4 {
      font-size: 22px;
      color: var(--color-aws-dark);
      margin-top: var(--spacing-sm);
      margin-bottom: var(--spacing-sm);
    }

    .step-card p {
      font-size: 20px;
      color: var(--color-text-secondary);
    }

    /* ========================================
       Why GA Section - Feature Grid
       ======================================== */
    .feature-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-base);
    }

    .feature-card {
      background: var(--color-bg-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      border-left: 4px solid var(--color-info);
      transition: transform var(--transition-base);
    }

    .feature-card:hover {
      transform: translateY(-2px);
    }

    .feature-card:nth-child(2) {
      border-left-color: var(--color-success);
    }

    .feature-card:nth-child(3) {
      border-left-color: var(--color-aws-orange-original);
    }

    .feature-card:nth-child(4) {
      border-left-color: #8B5CF6;
    }

    .feature-card h4 {
      font-size: 22px;
      color: var(--color-aws-dark);
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .feature-card p {
      font-size: 20px;
      color: var(--color-text-secondary);
    }

    /* ========================================
       Architecture Pattern Cards
       ======================================== */
    .arch-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-xl);
      margin: var(--spacing-xl) 0;
    }

    .arch-card {
      background: var(--color-bg-white);
      border: 2px solid var(--color-border-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-xl);
      transition: box-shadow var(--transition-base);
    }

    .arch-card:hover {
      box-shadow: var(--shadow-md);
    }

    .arch-card-badge {
      display: inline-block;
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 20px;
      font-weight: 600;
      margin-bottom: var(--spacing-sm);
    }

    .arch-card-badge--basic {
      background: #DBEAFE;
      color: #1D4ED8;
    }

    .arch-card-badge--advanced {
      background: #EDE9FE;
      color: #6D28D9;
    }

    .arch-card h4 {
      font-size: 24px;
      color: var(--color-aws-dark);
      margin-bottom: var(--spacing-sm);
    }

    .arch-card p {
      font-size: 20px;
      color: var(--color-text-secondary);
      margin-bottom: var(--spacing-md);
    }

    .arch-service-list {
      list-style: none;
      padding: 0;
    }

    .arch-service-list li {
      padding: 6px 0;
      font-size: 20px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .arch-service-list li::before {
      content: "→";
      color: var(--color-info);
      font-weight: 700;
    }

    /* ========================================
       Code Example Section
       ======================================== */
    .code-tabs {
      display: flex;
      gap: 0;
      margin-bottom: 0;
    }

    .code-tab {
      background: #E5E7EB;
      border: none;
      padding: var(--spacing-sm) var(--spacing-base);
      font-size: 20px;
      font-weight: 600;
      cursor: pointer;
      border-radius: var(--radius-md) var(--radius-md) 0 0;
      color: var(--color-text-secondary);
      transition: background var(--transition-base), color var(--transition-base);
    }

    .code-tab.active {
      background: var(--color-aws-dark);
      color: var(--color-text-white);
    }

    .code-tab:hover:not(.active) {
      background: #D1D5DB;
    }

    .code-panel {
      display: none;
      background: var(--color-aws-dark);
      border-radius: 0 var(--radius-md) var(--radius-md) var(--radius-md);
      padding: var(--spacing-xl);
      overflow-x: auto;
    }

    .code-panel.active {
      display: block;
    }

    .code-panel pre {
      margin: 0;
      font-family: "Courier New", Consolas, monospace;
      font-size: 20px;
      line-height: 1.5;
      color: #E5E7EB;
      white-space: pre;
    }

    .code-comment {
      color: #6B7280;
    }

    .code-keyword {
      color: #93C5FD;
    }

    .code-string {
      color: #86EFAC;
    }

    .code-value {
      color: #FCD34D;
    }

    /* ========================================
       IoT Challenge Section
       ======================================== */
    .challenge-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-base);
      margin-top: var(--spacing-xl);
    }

    .challenge-card {
      background: var(--color-bg-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      text-align: center;
      border: 2px solid transparent;
      transition: border-color var(--transition-base);
    }

    .challenge-card:hover {
      border-color: var(--color-aws-orange-original);
    }

    .challenge-icon {
      font-size: 44px;
      margin-bottom: var(--spacing-sm);
    }

    .challenge-card h4 {
      font-size: 22px;
      color: var(--color-aws-dark);
      margin-bottom: 8px;
    }

    .challenge-card p {
      font-size: 20px;
      color: var(--color-text-secondary);
    }

    /* ========================================
       FAQ Accordion
       ======================================== */
    .faq-item {
      border: 1px solid var(--color-border-light);
      border-radius: var(--radius-md);
      margin-bottom: var(--spacing-sm);
      overflow: hidden;
    }

    .faq-question {
      width: 100%;
      background: var(--color-bg-light);
      border: none;
      padding: var(--spacing-base) var(--spacing-lg);
      font-size: 22px;
      font-weight: 600;
      color: var(--color-aws-dark);
      text-align: left;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      transition: background var(--transition-base);
      font-family: inherit;
    }

    .faq-question:hover {
      background: #F3F4F6;
    }

    .faq-arrow {
      font-size: 20px;
      transition: transform var(--transition-base);
      color: var(--color-text-secondary);
    }

    .faq-item.open .faq-arrow {
      transform: rotate(180deg);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
    }

    .faq-item.open .faq-answer {
      max-height: 600px;
      padding: var(--spacing-base) var(--spacing-lg) var(--spacing-lg);
    }

    .faq-answer p {
      font-size: 20px;
      color: var(--color-text-secondary);
      line-height: 1.7;
    }

    /* ========================================
       Exam Tip
       ======================================== */
    .exam-tip {
      background: linear-gradient(135deg, #EEF2FF, #E8EAFF);
      border: 2px solid #818CF8;
      border-radius: var(--radius-lg);
      padding: var(--spacing-xl);
      margin: var(--spacing-xl) 0;
    }

    .exam-tip h3 {
      font-size: 24px;
      color: #4338CA;
      margin-bottom: var(--spacing-md);
      display: flex;
      align-items: center;
      gap: var(--spacing-sm);
    }

    .exam-tip p {
      font-size: 20px;
      color: var(--color-text-primary);
      margin-bottom: var(--spacing-sm);
    }

    .exam-tip p:last-child {
      margin-bottom: 0;
    }

    /* ========================================
       Best Practice Cards
       ======================================== */
    .bp-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: var(--spacing-base);
    }

    .bp-card {
      background: var(--color-bg-light);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      border-top: 4px solid var(--color-success);
    }

    .bp-card h4 {
      font-size: 22px;
      color: var(--color-aws-dark);
      margin-bottom: 8px;
    }

    .bp-card p {
      font-size: 20px;
      color: var(--color-text-secondary);
    }

    /* ========================================
       Summary Section
       ======================================== */
    .summary-section {
      background: linear-gradient(135deg, var(--color-aws-dark), #374151);
      color: var(--color-text-white);
      border-radius: var(--radius-xl);
      padding: var(--spacing-2xl);
      margin: var(--spacing-xl) 0;
      text-align: center;
    }

    .summary-section h2 {
      font-size: 30px;
      margin-bottom: var(--spacing-lg);
      color: var(--color-aws-orange-original);
    }

    .summary-section p {
      font-size: 22px;
      color: rgba(255, 255, 255, 0.85);
      max-width: 800px;
      margin: 0 auto var(--spacing-xl);
    }

    .summary-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: var(--spacing-base);
    }

    .summary-item {
      background: rgba(255, 255, 255, 0.08);
      border-radius: var(--radius-lg);
      padding: var(--spacing-lg);
      border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .summary-item-icon {
      font-size: 36px;
      margin-bottom: var(--spacing-sm);
    }

    .summary-item h4 {
      font-size: 22px;
      color: var(--color-aws-orange-original);
      margin-bottom: 8px;
    }

    .summary-item p {
      font-size: 20px;
      color: rgba(255, 255, 255, 0.75);
      margin: 0;
    }

    /* ========================================
       Responsive
       ======================================== */
    @media (max-width: 768px) {
      .conclusion-grid,
      .analogy-mapping,
      .comparison-grid,
      .step-flow,
      .feature-grid,
      .arch-grid,
      .challenge-grid,
      .bp-grid {
        grid-template-columns: 1fr;
      }

      .summary-grid {
        grid-template-columns: 1fr;
      }

      .hero h1 {
        font-size: 30px;
      }

      .section {
        padding: var(--spacing-xl);
      }
    }