:root {
            --primary-color: #2c7da0;
            --secondary-color: #a9d6e5;
            --accent-color: #01497c;
            --light-gray: #f8f9fa;
            --border-color: #eaeaea;
            --text-color: #333;
            --text-muted: #6c757d;
            --success-color: #28a745;
            --warning-color: #ffc107;
            --danger-color: #dc3545;
            --electronics-green: #198754;
            --electronics-blue: #0d6efd;
            --electronics-orange: #fd7e14;
            --electronics-purple: #6f42c1;
            --electronics-yellow: #ffc107;
        }
          
        .electronics-info-box {
            background-color: rgba(111, 66, 193, 0.05);
            border-left: 3px solid var(--electronics-purple);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
    
        /* Transistor specific styling */
        .transistor-type-selector {
            display: flex;
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 4px;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }
        
        .type-btn {
            flex: 1;
            text-align: center;
            padding: 0.75rem;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
            min-width: 120px;
            margin: 2px;
        }
        
        .type-btn.active {
            background-color: var(--electronics-purple);
            color: white;
        }
        
        .type-btn:hover:not(.active) {
            background-color: rgba(111, 66, 193, 0.1);
        }
        
        /* Circuit Diagram Styles */
        .circuit-diagram {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            text-align: center;
        }
        
        .circuit-svg {
            width: 100%;
            height: 200px;
            overflow: visible;
        }
        
        .circuit-line {
            stroke: var(--text-color);
            stroke-width: 2;
        }
        
        .circuit-resistor {
            stroke: var(--electronics-purple);
            stroke-width: 2;
        }
        
        .circuit-transistor {
            stroke: var(--primary-color);
            stroke-width: 2;
        }
        
        .circuit-label {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            font-size: 12px;
            fill: var(--text-muted);
        }
        
        .circuit-voltage {
            fill: var(--electronics-green);
            font-weight: bold;
        }
        
        .circuit-ground {
            fill: var(--text-color);
        }
        
        /* Toast notifications */
        .toast-container {
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1050;
        }
        
        /* Action buttons */
        .action-btn {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            padding: 0.5rem 1rem;
            margin-left: 0.5rem;
            transition: all 0.3s;
            color: var(--text-color);
        }
        
        .action-btn:hover {
            background-color: var(--light-gray);
            color: var(--primary-color);
        }
        
        /* Input group styling */
        .input-group {
            margin-bottom: 1rem;
        }
        
        /* Reference table */
        .reference-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .reference-table th, .reference-table td {
            padding: 0.75rem;
            text-align: left;
            border: 1px solid var(--border-color);
        }
        
        .reference-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .reference-table tr:nth-child(even) {
            background-color: rgba(44, 125, 160, 0.05);
        }
        
        .generating-indicator {
            display: none;
            text-align: center;
            padding: 1rem;
            color: var(--text-muted);
        }
        
        /* Transistor result styles */
        .resistor-value-display {
            font-size: 2.5rem;
            font-weight: 700;
            text-align: center;
            color: var(--electronics-purple);
            margin: 1.5rem 0;
            padding: 1.5rem;
            background-color: rgba(111, 66, 193, 0.05);
            border-radius: 8px;
            border: 2px solid var(--electronics-purple);
        }
        
        .standard-value {
            background-color: rgba(40, 167, 69, 0.1);
            padding: 0.75rem;
            border-radius: 6px;
            margin: 1rem 0;
            border-left: 4px solid var(--success-color);
        }
        
        .warning-box {
            background-color: rgba(255, 193, 7, 0.1);
            border-left: 4px solid var(--warning-color);
            padding: 1rem;
            margin: 1rem 0;
            border-radius: 0 4px 4px 0;
        }
        
        .transistor-pinout {
            display: flex;
            justify-content: space-around;
            margin: 1.5rem 0;
            flex-wrap: wrap;
        }
        
        .pin {
            text-align: center;
            padding: 1rem;
            border-radius: 8px;
            background-color: white;
            border: 1px solid var(--border-color);
            min-width: 120px;
            margin: 0.5rem;
        }
        
        .pin-name {
            font-weight: 600;
            color: var(--electronics-purple);
        }
        
        .pin-description {
            font-size: 0.9rem;
            color: var(--text-muted);
        }
        
        .calculation-formula {
            font-family: 'Courier New', monospace;
            background-color: #f8f9fa;
            padding: 1rem;
            border-radius: 6px;
            border-left: 4px solid var(--electronics-blue);
            margin: 1.5rem 0;
        }
        
        .chart-container {
            position: relative;
            height: 400px;
            width: 100%;
            margin: 2rem 0;
        }
        
        .chart-description {
            text-align: center;
            color: var(--text-muted);
            margin-bottom: 1rem;
            font-style: italic;
        }
        
        /* Chart controls */
        .chart-controls {
            display: flex;
            justify-content: center;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
            gap: 1rem;
        }
        
        .chart-control-btn {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            padding: 0.5rem 1rem;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .chart-control-btn.active {
            background-color: var(--electronics-purple);
            color: white;
            border-color: var(--electronics-purple);
        }
        
        .chart-control-btn:hover:not(.active) {
            background-color: rgba(111, 66, 193, 0.1);
        }
        
        /* Input validation */
        .is-invalid {
            border-color: var(--danger-color);
        }
        
        .invalid-feedback {
            color: var(--danger-color);
            font-size: 0.875rem;
            margin-top: 0.25rem;
        }