:root {
            --primary-color: #2c7da0;
            --secondary-color: #a9d6e5;
            --accent-color: #01497c;
            --light-gray: #f8f9fa;
            --border-color: #eaeaea;
            --text-color: #333;
            --text-muted: #6c757d;
            --correct-color: #28a745;
            --incorrect-color: #dc3545;
        }
        
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: white;
            color: var(--text-color);
            line-height: 1.6;
        }
        
        .container {
            max-width: 1200px;
        }
        .test-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}
        /* Header Styles */
        .navbar {
            background-color: white;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            border-bottom: 1px solid var(--border-color);
            padding: 0.75rem 0;
        }
         .stat-card {
            background: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
        }
        
        .stat-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--primary-color);
        }
        
        .stat-value {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--accent-color);
            margin-bottom: 0.5rem;
        }
        
        .stat-desc {
            color: var(--text-muted);
        }
        .navbar-brand {
            font-weight: 700;
            color: var(--primary-color);
            font-size: 1.5rem;
        }
        
        .nav-link {
            color: #555;
            font-weight: 500;
            transition: color 0.3s;
            padding: 0.5rem 1rem;
            border-radius: 6px;
        }
        
        .nav-link:hover, .nav-link.active {
            color: var(--primary-color);
            background-color: rgba(44, 125, 160, 0.1);
        }
        
        .page-header {
            background: linear-gradient(135deg, rgba(169, 214, 229, 0.4) 0%, rgba(44, 125, 160, 0.4) 100%);
            padding: 1.5rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid rgba(44, 125, 160, 0.2);
            position: relative;
            overflow: hidden;
        }
        
        .page-header::before {
            content: "";
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background-image: radial-gradient(rgba(255,255,255,0.8) 1px, transparent 1px);
            background-size: 20px 20px;
            opacity: 0.3;
            transform: rotate(30deg);
        }
        
        .breadcrumb {
            background-color: transparent;
            padding: 0.5rem 0;
            margin-bottom: 0.5rem;
        }
        
        .breadcrumb-item a {
            color: var(--text-muted);
            text-decoration: none;
        }
        
        .breadcrumb-item.active {
            color: var(--text-color);
        }
        
        /* Tool Card Styles */
        .tool-card {
            background: white;
            border-radius: 8px;
            border: 1px solid var(--border-color);
            padding: 2rem;
            margin-bottom: 1.5rem;
            box-shadow: 0 2px 8px rgba(0,0,0,0.03);
        }
        
        .tool-header {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 25px;
            border-bottom: 1px solid var(--border-color);
        }
        
        .tool-header h2 {
            font-weight: 600;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }
        
        /* Input/Output Areas */
        .input-output-container {
            display: flex;
            flex-direction: column;
            gap: 1.5rem;
        }
        
        .io-area {
            background-color: var(--light-gray);
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
        }
        
        .io-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1rem;
        }
        
        .io-title {
            font-weight: 600;
            color: var(--primary-color);
        }
        
        .io-controls {
            display: flex;
            gap: 0.5rem;
        }
        
        .io-content {
            position: relative;
        }
        
        .io-textarea {
            width: 100%;
            min-height: 200px;
            padding: 1rem;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            font-family: 'Courier New', monospace;
            font-size: 0.95rem;
            resize: vertical;
        }
        
        .io-textarea:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 0.2rem rgba(44, 125, 160, 0.1);
        }
        
        .char-count {
            position: absolute;
            bottom: 10px;
            right: 10px;
            background-color: rgba(255, 255, 255, 0.8);
            padding: 0.25rem 0.5rem;
            border-radius: 4px;
            font-size: 0.8rem;
            color: var(--text-muted);
        }
        
        /* Tool Controls */
        .tool-controls {
            display: flex;
            justify-content: center;
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .btn-lg {
            padding: 0.75rem 2rem;
            font-size: 1.1rem;
            font-weight: 600;
        }
        
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
        }
        
        .btn-secondary {
            background-color: var(--secondary-color);
            border-color: var(--secondary-color);
            color: var(--text-color);
        }
        
        .btn-secondary:hover {
            background-color: #8fc4d9;
            border-color: #8fc4d9;
        }
        
        .btn-success {
            background-color: var(--correct-color);
            border-color: var(--correct-color);
        }
        
        .btn-danger {
            background-color: var(--incorrect-color);
            border-color: var(--incorrect-color);
        }
        
        /* Preview Area */
        .preview-container {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            margin-top: 1.5rem;
            border: 1px solid var(--border-color);
        }
        
        .preview-header {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
            padding-bottom: 0.5rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .preview-content {
            min-height: 150px;
            padding: 1rem;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            background-color: var(--light-gray);
        }
        
        /* Information Section */
        .info-section {
            background-color: rgba(44, 125, 160, 0.05);
            border-left: 3px solid var(--primary-color);
            padding: 1.5rem;
            border-radius: 0 6px 6px 0;
            margin: 1.5rem 0;
        }
        
        .info-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--primary-color);
        }
        
        /* HTML Entities Table */
        .entities-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .entities-table th {
            background-color: var(--primary-color);
            color: white;
            padding: 0.75rem;
            text-align: left;
        }
        
        .entities-table td {
            padding: 0.75rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .entities-table tr:nth-child(even) {
            background-color: var(--light-gray);
        }
        
        .entity-code {
            font-family: 'Courier New', monospace;
            font-weight: 600;
        }
        
        /* Responsive Adjustments */
        @media (max-width: 768px) {
            .tool-card {
                padding: 1.5rem;
            }
            
            .tool-controls {
                flex-wrap: wrap;
            }
            
            .btn-lg {
                width: 100%;
                margin-bottom: 0.5rem;
            }
        }
        
        /* Feature Cards */
        .feature-cards {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }
        
        .feature-card {
            background: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            transition: transform 0.3s, box-shadow 0.3s;
        }
        
        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 6px 15px rgba(0,0,0,0.1);
        }
        
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        
        .feature-title {
            font-weight: 600;
            margin-bottom: 0.75rem;
            color: var(--accent-color);
        }
        
        /* Use Cases */
        .use-cases {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }
        
        .use-case {
            background: rgba(44, 125, 160, 0.05);
            border-radius: 8px;
            padding: 1.5rem;
            border-left: 3px solid var(--primary-color);
        }
        
        .use-case-title {
            font-weight: 600;
            margin-bottom: 0.75rem;
            color: var(--primary-color);
        }
        
        /* Comparison Table */
        .comparison-table {
            width: 100%;
            border-collapse: collapse;
            margin: 2rem 0;
        }
        
        .comparison-table th {
            background-color: var(--primary-color);
            color: white;
            padding: 1rem;
            text-align: left;
        }
        
        .comparison-table td {
            padding: 1rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .comparison-table tr:nth-child(even) {
            background-color: var(--light-gray);
        }
        
        .check-icon {
            color: var(--correct-color);
            font-size: 1.2rem;
        }
        
        .x-icon {
            color: var(--incorrect-color);
            font-size: 1.2rem;
        }