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

        body {
            font-family: 'Sarabun', 'Prompt', 'Segoe UI', system-ui, -apple-system, sans-serif;
            background: #f0f2f5;
            color: #1e293b;
            line-height: 1.6;
        }

        /* Header */
        .header {
            background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
            color: white;
            padding: 2rem 0;
            border-bottom: 4px solid #3b82f6;
        }

        .header-content {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 2rem;
        }

        .header h1 {
            font-size: 2rem;
            margin-bottom: 0.5rem;
            font-weight: 600;
        }

        .header .subtitle {
            font-size: 1.2rem;
            color: #94a3b8;
        }

        .header .course-info {
            margin-top: 0.5rem;
            font-size: 0.9rem;
            color: #64748b;
        }

        /* Navigation */
        .nav-bar {
            background: white;
            border-bottom: 1px solid #e2e8f0;
            position: sticky;
            top: 0;
            z-index: 100;
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
        }

        .nav-links {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0.75rem 2rem;
            display: flex;
            gap: 2rem;
            flex-wrap: wrap;
        }

        .nav-links a {
            color: #475569;
            text-decoration: none;
            font-weight: 500;
            padding: 0.25rem 0;
            transition: all 0.3s;
            border-bottom: 2px solid transparent;
        }

        .nav-links a:hover {
            color: #3b82f6;
            border-bottom-color: #3b82f6;
        }

        /* Container */
        .container {
            max-width: 1280px;
            margin: 2rem auto;
            padding: 0 2rem;
        }

        /* Cards - Square Box Style */
        .card {
            background: white;
            border: 1px solid #e2e8f0;
            border-radius: 12px;
            box-shadow: 0 1px 3px rgba(0,0,0,0.05);
            margin-bottom: 1.75rem;
            overflow: hidden;
            transition: box-shadow 0.2s;
        }

        .card:hover {
            box-shadow: 0 4px 12px rgba(0,0,0,0.08);
        }

        .card-header {
            background: #f8fafc;
            padding: 1rem 1.5rem;
            border-bottom: 1px solid #e2e8f0;
        }

        .card-header h2 {
            color: #0f172a;
            font-size: 1.25rem;
            font-weight: 600;
            margin: 0;
        }

        .card-header h3 {
            color: #334155;
            font-size: 1.1rem;
            font-weight: 600;
            margin: 0;
        }

        .card-body {
            padding: 1.5rem;
        }

        /* Grid Layout */
        .grid-2 {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 1.25rem;
        }

        .grid-3 {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 1.25rem;
        }

        .grid-4 {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1.25rem;
        }

        /* Box Components */
        .objective-box {
            background: #f8fafc;
            border: 1px solid #e2e8f0;
            border-radius: 10px;
            padding: 1.25rem;
            transition: all 0.2s;
        }

        .objective-box h4 {
            color: #3b82f6;
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 0.75rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid #e2e8f0;
        }

        .objective-box ul {
            margin-left: 1.25rem;
            color: #334155;
        }

        .objective-box li {
            margin: 0.5rem 0;
        }

        /* KPI Cards */
        .kpi-card {
            background: #f8fafc;
            border: 1px solid #e2e8f0;
            border-radius: 10px;
            padding: 1rem;
            text-align: center;
            transition: all 0.2s;
        }

        .kpi-card .metric {
            font-size: 1.5rem;
            font-weight: 700;
            color: #3b82f6;
            margin-bottom: 0.25rem;
        }

        .kpi-card p {
            font-size: 0.85rem;
            color: #64748b;
        }

        /* Process Flow */
        .process-flow {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 0.75rem;
            margin: 1.25rem 0;
        }

        .process-step {
            background: #1e293b;
            color: white;
            padding: 0.6rem 1.25rem;
            border-radius: 8px;
            text-align: center;
            font-weight: 500;
            font-size: 0.85rem;
            min-width: 90px;
        }

        /* Tables */
        .info-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1rem 0;
            font-size: 0.9rem;
        }

        .info-table th,
        .info-table td {
            border: 1px solid #e2e8f0;
            padding: 0.75rem;
            text-align: left;
        }

        .info-table th {
            background: #f8fafc;
            color: #0f172a;
            font-weight: 600;
        }

        .info-table tr:hover {
            background: #faf9fe;
        }

        /* Code Block */
        .code-block {
            background: #1e293b;
            color: #e2e8f0;
            padding: 1rem;
            border-radius: 10px;
            overflow-x: auto;
            font-family: 'Courier New', 'Fira Code', monospace;
            font-size: 0.8rem;
            margin: 1rem 0;
        }

        .code-block pre {
            margin: 0;
            white-space: pre-wrap;
            word-break: break-word;
        }

        /* Activity Box */
        .activity-box {
            background: #fef9e6;
            border: 1px solid #fde047;
            border-radius: 10px;
            padding: 1.25rem;
            margin: 1rem 0;
        }

        .activity-box h4 {
            color: #b45309;
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 0.75rem;
        }

        .activity-box ol, .activity-box ul {
            margin-left: 1.25rem;
        }

        .activity-box li {
            margin: 0.4rem 0;
        }

        /* Tool Badge */
        .tool-badge {
            display: inline-block;
            background: #e2e8f0;
            color: #1e293b;
            padding: 0.2rem 0.7rem;
            border-radius: 20px;
            font-size: 0.75rem;
            margin: 0.2rem;
        }

        /* Review List */
        .review-list {
            margin-left: 1.5rem;
        }

        .review-list li {
            margin: 0.75rem 0;
        }

        /* Performance Monitor Tool */
        .perf-monitor {
            background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
            border: 2px solid #3b82f6;
            border-radius: 16px;
            padding: 1.5rem;
            margin: 1.5rem 0;
        }

        .perf-monitor h3 {
            color: #0f172a;
            margin-bottom: 1rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .monitor-controls {
            display: flex;
            gap: 1rem;
            flex-wrap: wrap;
            margin-bottom: 1.5rem;
        }

        .btn {
            padding: 0.6rem 1.2rem;
            border: none;
            border-radius: 8px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s;
            font-family: inherit;
        }

        .btn-primary {
            background: #3b82f6;
            color: white;
        }

        .btn-primary:hover {
            background: #2563eb;
            transform: translateY(-1px);
        }

        .btn-secondary {
            background: #64748b;
            color: white;
        }

        .btn-secondary:hover {
            background: #475569;
        }

        .btn-danger {
            background: #ef4444;
            color: white;
        }

        .btn-danger:hover {
            background: #dc2626;
        }

        .btn-success {
            background: #10b981;
            color: white;
        }

        .btn-success:hover {
            background: #059669;
        }

        .metrics-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 1rem;
            margin: 1rem 0;
        }

        .metric-card {
            background: white;
            border: 1px solid #e2e8f0;
            border-radius: 12px;
            padding: 1rem;
            text-align: center;
        }

        .metric-card .metric-label {
            font-size: 0.75rem;
            color: #64748b;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .metric-card .metric-value {
            font-size: 1.8rem;
            font-weight: 700;
            color: #0f172a;
        }

        .metric-card .metric-unit {
            font-size: 0.8rem;
            color: #64748b;
        }

        .metric-card.warning .metric-value {
            color: #e67e22;
        }

        .metric-card.critical .metric-value {
            color: #ef4444;
        }

        .metric-card.success .metric-value {
            color: #10b981;
        }

        .log-container {
            background: #0f172a;
            border-radius: 12px;
            padding: 1rem;
            max-height: 300px;
            overflow-y: auto;
            font-family: 'Courier New', monospace;
            font-size: 0.8rem;
            margin-top: 1rem;
        }

        .log-entry {
            padding: 0.3rem 0;
            border-bottom: 1px solid #1e293b;
            color: #94a3b8;
        }

        .log-entry.info {
            color: #3b82f6;
        }

        .log-entry.warning {
            color: #f59e0b;
        }

        .log-entry.error {
            color: #ef4444;
        }

        .log-entry.success {
            color: #10b981;
        }

        .progress-bar {
            height: 6px;
            background: #e2e8f0;
            border-radius: 3px;
            overflow: hidden;
            margin-top: 0.5rem;
        }

        .progress-fill {
            height: 100%;
            background: #3b82f6;
            width: 0%;
            transition: width 0.3s;
        }
        hr {
            border: none;
            border-top: 1px solid #e2e8f0;
            margin: 1.5rem 0;
        }
        .intro-card {
            background: linear-gradient(135deg, #f8fafc 0%, #eef2ff 100%);
            border-left: 5px solid #3b82f6;
            border-radius: 12px;
            padding: 1.5rem;
            margin-bottom: 1.75rem;
        }
        .intro-card h3 {
            color: #1e293b;
            font-size: 1.3rem;
            margin-bottom: 0.75rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .intro-card .highlight {
            background: #3b82f6;
            color: white;
            padding: 0.2rem 0.6rem;
            border-radius: 20px;
            font-size: 0.8rem;
            display: inline-block;
        }
        .intro-stats {
            display: flex;
            gap: 1rem;
            margin-top: 1rem;
            flex-wrap: wrap;
        }
        .intro-stat {
            background: white;
            padding: 0.5rem 1rem;
            border-radius: 8px;
            font-size: 0.85rem;
            box-shadow: 0 1px 2px rgba(0,0,0,0.05);
        }
        .intro-stat strong {
            color: #3b82f6;
        }

        /* Step Detail Styles */
        .step-detail {
            margin: 1.5rem 0;
            border: 1px solid #e2e8f0;
            border-radius: 12px;
            overflow: hidden;
        }
        .step-header {
            background: #f1f5f9;
            padding: 0.75rem 1rem;
            font-weight: 600;
            color: #0f172a;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            transition: background 0.2s;
        }
        .step-header:hover {
            background: #e2e8f0;
        }
        .step-header .step-number {
            background: #3b82f6;
            color: white;
            width: 28px;
            height: 28px;
            border-radius: 50%;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            font-size: 0.8rem;
            margin-right: 0.75rem;
        }
        .step-header .toggle-icon {
            font-size: 1.2rem;
            transition: transform 0.3s;
        }
        .step-header.collapsed .toggle-icon {
            transform: rotate(-90deg);
        }
        .step-content {
            padding: 1rem;
            border-top: 1px solid #e2e8f0;
            display: block;
        }
        .step-content.collapsed {
            display: none;
        }
        .case-table {
            width: 100%;
            border-collapse: collapse;
            margin: 0.5rem 0;
            font-size: 0.85rem;
        }
        .case-table th, .case-table td {
            border: 1px solid #e2e8f0;
            padding: 0.5rem;
            vertical-align: top;
        }
        .case-table th {
            background: #f8fafc;
        }
        .five-whys-box {
            background: #f1f5f9;
            padding: 1rem;
            border-radius: 8px;
            margin: 0.5rem 0;
        }
        .root-cause-box {
            background: #3b82f6;
            color: white;
            padding: 0.75rem;
            border-radius: 8px;
            margin-top: 0.5rem;
        }

        /* Footer */
        .footer {
            background: #0f172a;
            color: #94a3b8;
            text-align: center;
            padding: 1.5rem;
            margin-top: 2rem;
            border-top: 1px solid #1e293b;
            font-size: 0.85rem;
        }

        /* Responsive */
        @media (max-width: 1024px) {
            .grid-4 {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 768px) {
            .header h1 {
                font-size: 1.5rem;
            }
            .container {
                padding: 0 1rem;
            }
            .grid-2, .grid-3, .grid-4 {
                grid-template-columns: 1fr;
            }
            .process-step {
                min-width: 70px;
                padding: 0.4rem 0.8rem;
                font-size: 0.7rem;
            }
            .nav-links {
                gap: 1rem;
                font-size: 0.85rem;
            }
            .metrics-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        /* Print Styles */
        @media print {
            .nav-bar, .footer, .perf-monitor {
                display: none;
            }
            .card {
                break-inside: avoid;
                border: 1px solid #ccc;
            }
            body {
                background: white;
            }
            .step-header {
                break-inside: avoid;
            }
        }