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

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            background: linear-gradient(135deg, #0a0a0f 0%, #1a1a2e 50%, #16213e 100%);
            min-height: 100vh;
            color: #e0e0e0;
            padding: 20px;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
        }

        header {
            background: rgba(255, 255, 255, 0.05);
            backdrop-filter: blur(10px);
            border-radius: 16px;
            padding: 20px 30px;
            margin-bottom: 20px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        h1 {
            font-size: 28px;
            background: linear-gradient(135deg, #4facfe, #00f2fe);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            margin-bottom: 8px;
        }

        .subtitle {
            color: #a0a0a0;
            font-size: 14px;
        }

        .format-badge {
            display: inline-block;
            padding: 6px 14px;
            background: linear-gradient(135deg, #059669, #047857);
            color: white;
            border-radius: 20px;
            font-size: 11px;
            font-weight: 600;
            text-transform: uppercase;
            margin-bottom: 15px;
        }

        .main-content {
            background: rgba(255, 255, 255, 0.05);
            backdrop-filter: blur(10px);
            border-radius: 16px;
            padding: 0;
            border: 1px solid rgba(255, 255, 255, 0.1);
            overflow: hidden;
            min-height: 400px;
        }

        .loading {
            text-align: center;
            padding: 60px 20px;
        }

        .loading-spinner {
            border: 4px solid rgba(255, 255, 255, 0.3);
            border-top: 4px solid white;
            border-radius: 50%;
            width: 50px;
            height: 50px;
            animation: spin 1s linear infinite;
            margin: 0 auto 20px;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        .ke-header {
            padding: 25px 30px;
            background: linear-gradient(135deg, rgba(5, 150, 105, 0.15), rgba(4, 120, 87, 0.15));
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }

        .concept-title {
            font-size: 32px;
            margin-bottom: 10px;
            color: #fff;
        }

        .breadcrumb {
            color: #a0a0a0;
            font-size: 14px;
            margin-bottom: 15px;
        }

        .breadcrumb span {
            color: #4facfe;
        }

        .teaser {
            color: #c0c0c0;
            line-height: 1.6;
            font-size: 15px;
        }

        .tabs-container {
            display: flex;
            background: rgba(0, 0, 0, 0.2);
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            overflow-x: auto;
        }

        .tab {
            padding: 15px 25px;
            cursor: pointer;
            transition: all 0.3s ease;
            border-bottom: 3px solid transparent;
            white-space: nowrap;
            color: #a0a0a0;
            font-weight: 500;
            font-size: 14px;
        }

        .tab:hover {
            background: rgba(255, 255, 255, 0.05);
            color: #e0e0e0;
        }

        .tab.active {
            background: rgba(5, 150, 105, 0.1);
            border-bottom-color: #059669;
            color: #00f2fe;
        }

        .tab-icon {
            margin-right: 8px;
        }

        .tab-content {
            display: none;
            padding: 30px;
        }

        .tab-content.active {
            display: block;
            animation: fadeIn 0.3s ease;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .section-title {
            font-size: 24px;
            margin-bottom: 20px;
            color: #00f2fe;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .section-content {
            line-height: 1.8;
            color: #d0d0d0;
            font-size: 16px;
            margin-bottom: 25px;
        }

        .section-content p {
            margin-bottom: 15px;
        }

        .enhancement-bar {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
            padding: 20px;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 10px;
            margin-top: 20px;
        }

        .enhancement-btn {
            padding: 10px 18px;
            border: none;
            border-radius: 8px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 13px;
            display: flex;
            align-items: center;
            gap: 6px;
        }

        .enhancement-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
        }

        .btn-air {
            background: linear-gradient(135deg, #10b981, #059669);
            color: white;
        }

        .btn-expand {
            background: linear-gradient(135deg, #4facfe, #00f2fe);
            color: white;
        }

        .btn-simplify {
            background: linear-gradient(135deg, #f093fb, #f5576c);
            color: white;
        }

        .btn-examples {
            background: linear-gradient(135deg, #ffd93d, #ffb74d);
            color: #333;
        }

        .btn-clarify {
            background: linear-gradient(135deg, #7c3aed, #6d28d9);
            color: white;
        }

        .related-concepts {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 15px;
            margin-top: 20px;
        }

        .related-card {
            background: rgba(255, 255, 255, 0.05);
            padding: 18px;
            border-radius: 10px;
            border: 1px solid rgba(255, 255, 255, 0.1);
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .related-card:hover {
            background: rgba(255, 255, 255, 0.1);
            transform: translateY(-4px);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
        }

        .related-card-title {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 8px;
            color: #4facfe;
        }

        .related-card-desc {
            font-size: 13px;
            color: #a0a0a0;
            line-height: 1.5;
        }

        .assessment-question {
            background: rgba(79, 172, 254, 0.05);
            padding: 20px;
            border-radius: 10px;
            border-left: 4px solid #4facfe;
            margin-bottom: 20px;
        }

        .question-number {
            color: #4facfe;
            font-weight: 700;
            font-size: 18px;
            margin-bottom: 10px;
        }

        .question-text {
            color: #e0e0e0;
            line-height: 1.6;
            font-size: 16px;
        }

        .action-bar {
            display: flex;
            gap: 15px;
            justify-content: center;
            padding: 25px;
            background: rgba(0, 0, 0, 0.2);
            border-top: 1px solid rgba(255, 255, 255, 0.1);
        }

        .action-btn {
            padding: 12px 28px;
            border: none;
            border-radius: 10px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 14px;
            text-decoration: none;
            display: inline-block;
        }

        .nav-btn {
            background: rgba(255, 255, 255, 0.1);
            color: #4facfe;
            border: 2px solid #4facfe;
        }

        .nav-btn:hover {
            background: #4facfe;
            color: white;
            transform: translateY(-2px);
        }

        .info-box {
            background: rgba(79, 172, 254, 0.1);
            border: 1px solid rgba(79, 172, 254, 0.3);
            border-radius: 10px;
            padding: 20px;
            margin-top: 20px;
        }

        .info-box h3 {
            color: #4facfe;
            margin-bottom: 10px;
            font-size: 16px;
        }

        .info-box p {
            color: #c0c0c0;
            font-size: 14px;
            line-height: 1.6;
        }

        .error-message {
            background: rgba(239, 68, 68, 0.2);
            border: 2px solid rgba(239, 68, 68, 0.5);
            border-radius: 15px;
            padding: 30px;
            text-align: center;
        }

        .error-message h3 {
            color: #f87171;
            margin-bottom: 15px;
        }