: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;
            --multimeter-red: #d32f2f;
            --multimeter-black: #212121;
            --multimeter-yellow: #ffc107;
            --multimeter-green: #4caf50;
        }
     
        /* Multimeter Simulator Styles */
        .multimeter-container {
            display: flex;
            flex-direction: column;
            gap: 1.5rem;
        }
        
        .multimeter-display {
            background-color: var(--multimeter-black);
            border-radius: 8px;
            padding: 1.5rem;
            margin-bottom: 1.5rem;
            position: relative;
            overflow: hidden;
            min-height: 180px;
            display: flex;
            flex-direction: column;
            justify-content: center;
        }
        
        .multimeter-screen {
            background-color: #0a1f0a;
            border: 2px solid #2a3d2a;
            border-radius: 4px;
            padding: 1rem;
            font-family: 'Courier New', monospace;
            color: #7cfc00;
            text-shadow: 0 0 5px rgba(124, 252, 0, 0.5);
            min-height: 120px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            position: relative;
        }
        
        .screen-overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(to bottom, transparent 50%, rgba(0, 0, 0, 0.2) 50%);
            background-size: 100% 4px;
            pointer-events: none;
            opacity: 0.3;
        }
        
        .multimeter-reading {
            font-size: 2.5rem;
            font-weight: 700;
            text-align: center;
            margin-bottom: 0.5rem;
            letter-spacing: 1px;
        }
        
        .multimeter-units {
            font-size: 1.25rem;
            text-align: center;
            color: #9dff9d;
            margin-bottom: 0.5rem;
        }
        
        .multimeter-mode {
            font-size: 1rem;
            text-align: center;
            color: #7cfc00;
            margin-bottom: 0.5rem;
        }
        
        .multimeter-indicators {
            display: flex;
            justify-content: space-between;
            margin-top: 1rem;
            font-size: 0.9rem;
            color: #9dff9d;
        }
        
        .multimeter-controls {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 1rem;
            margin-bottom: 1.5rem;
        }
        
        .control-group {
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 1rem;
            border: 1px solid var(--border-color);
        }
        
        .control-label {
            font-weight: 600;
            margin-bottom: 0.75rem;
            color: var(--primary-color);
            display: flex;
            align-items: center;
        }
        
        .control-label i {
            margin-right: 0.5rem;
        }
        
        .mode-selector {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin-bottom: 1rem;
        }
        
        .mode-btn {
            padding: 0.5rem 1rem;
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 500;
        }
        
        .mode-btn:hover {
            background-color: #f8f9fa;
        }
        
        .mode-btn.active {
            background-color: var(--primary-color);
            color: white;
            border-color: var(--primary-color);
        }
        
        .range-selector {
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }
        
        .range-btn {
            padding: 0.5rem;
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            text-align: center;
        }
        
        .range-btn:hover {
            background-color: #f8f9fa;
        }
        
        .range-btn.active {
            background-color: var(--accent-color);
            color: white;
            border-color: var(--accent-color);
        }
        
        .probe-connections {
            display: flex;
            justify-content: space-around;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
            gap: 1rem;
        }
        
        .probe {
            display: flex;
            flex-direction: column;
            align-items: center;
            width: 140px;
        }
        
        .probe-label {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text-color);
        }
        
        .probe-connector {
            width: 80px;
            height: 40px;
            background-color: #6c757d;
            border-radius: 4px 4px 0 0;
            display: flex;
            justify-content: center;
            align-items: center;
            color: white;
            font-weight: 600;
        }
        
        .probe-wire {
            width: 10px;
            height: 100px;
            background-color: #333;
            position: relative;
        }
        
        .probe-tip {
            width: 20px;
            height: 40px;
            background-color: #d32f2f;
            border-radius: 10px 10px 0 0;
            position: absolute;
            bottom: 0;
            left: -5px;
        }
        
        .black-probe .probe-tip {
            background-color: #212121;
        }
        
        .circuit-diagram {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-bottom: 1.5rem;
        }
        
        .circuit-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }
        
        .circuit-canvas {
            width: 100%;
            height: 200px;
            background-color: #f8f9fa;
            border-radius: 4px;
            border: 1px solid var(--border-color);
            position: relative;
            overflow: hidden;
        }
        
        .circuit-element {
            position: absolute;
            display: flex;
            flex-direction: column;
            align-items: center;
            cursor: pointer;
            transition: transform 0.3s;
        }
        
        .circuit-element:hover {
            transform: scale(1.05);
        }
        
        .element-label {
            font-size: 0.8rem;
            font-weight: 600;
            margin-top: 0.25rem;
            color: var(--text-color);
            background-color: rgba(255, 255, 255, 0.8);
            padding: 0.1rem 0.4rem;
            border-radius: 2px;
        }
        
        .battery {
            width: 40px;
            height: 60px;
            background-color: #ffc107;
            border: 2px solid #e0a800;
            border-radius: 4px;
            position: relative;
        }
        
        .battery::before, .battery::after {
            content: '';
            position: absolute;
            background-color: #333;
        }
        
        .battery::before {
            width: 8px;
            height: 4px;
            top: -4px;
            left: 16px;
        }
        
        .battery::after {
            width: 4px;
            height: 8px;
            bottom: -8px;
            left: 18px;
        }
        
        .resistor {
            width: 60px;
            height: 20px;
            background-color: #f8f9fa;
            border: 2px solid #6c757d;
            border-radius: 10px;
            position: relative;
        }
        
        .resistor::before, .resistor::after {
            content: '';
            position: absolute;
            width: 10px;
            height: 2px;
            background-color: #333;
            top: 9px;
        }
        
        .resistor::before {
            left: -10px;
        }
        
        .resistor::after {
            right: -10px;
        }
        
        .led {
            width: 20px;
            height: 20px;
            background-color: #ff4444;
            border-radius: 50%;
            position: relative;
            box-shadow: 0 0 10px rgba(255, 68, 68, 0.7);
        }
        
        .led::before, .led::after {
            content: '';
            position: absolute;
            width: 10px;
            height: 2px;
            background-color: #333;
            top: 9px;
        }
        
        .led::before {
            left: -10px;
        }
        
        .led::after {
            right: -10px;
        }
        
        .wire {
            position: absolute;
            background-color: #333;
        }
        
        .horizontal-wire {
            height: 2px;
        }
        
        .vertical-wire {
            width: 2px;
        }
        
        .measurement-point {
            position: absolute;
            width: 12px;
            height: 12px;
            background-color: #d32f2f;
            border-radius: 50%;
            cursor: pointer;
            z-index: 10;
            transition: all 0.3s;
        }
        
        .measurement-point:hover {
            transform: scale(1.3);
            box-shadow: 0 0 10px rgba(211, 47, 47, 0.7);
        }
        
        .measurement-point.active {
            background-color: #4caf50;
            box-shadow: 0 0 10px rgba(76, 175, 80, 0.7);
        }
        
        .simulation-controls {
            display: flex;
            gap: 1rem;
            margin-top: 1.5rem;
            flex-wrap: wrap;
        }
        
        .sim-btn {
            padding: 0.75rem 1.5rem;
            font-weight: 600;
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            transition: all 0.3s;
        }
        
        .sim-btn i {
            font-size: 1.1rem;
        }
        
        .btn-simulate {
            background-color: var(--primary-color);
            color: white;
            border: none;
        }
        
        .btn-simulate:hover {
            background-color: var(--accent-color);
            transform: translateY(-2px);
        }
        
        .btn-reset {
            background-color: white;
            color: var(--text-color);
            border: 1px solid var(--border-color);
        }
        
        .btn-reset:hover {
            background-color: var(--light-gray);
        }
        
        .result-container {
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 1.5rem;
            margin-top: 1.5rem;
            border: 1px solid var(--border-color);
            display: none;
        }
        
        .result-title {
            font-weight: 600;
            margin-bottom: 0.75rem;
            color: var(--primary-color);
        }
        
        .result-content {
            word-break: break-all;
            padding: 12px;
            background-color: white;
            border-radius: 4px;
            border: 1px solid #eee;
            font-size: 0.95rem;
        }
        
        /* Educational Content */
        .section-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
            padding-bottom: 0.5rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .info-box {
            background-color: rgba(44, 125, 160, 0.05);
            border-left: 3px solid var(--primary-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .warning-box {
            background-color: rgba(255, 193, 7, 0.05);
            border-left: 3px solid var(--warning-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .danger-box {
            background-color: rgba(220, 53, 69, 0.05);
            border-left: 3px solid var(--danger-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .usage-step {
            display: flex;
            margin-bottom: 1.5rem;
            align-items: flex-start;
        }
        
        .step-number {
            width: 28px;
            height: 28px;
            background-color: var(--primary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 1rem;
            flex-shrink: 0;
            font-weight: 600;
            font-size: 0.9rem;
        }
        
        .multimeter-functions {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .function-card {
            background-color: white;
            border-radius: 6px;
            padding: 1rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
        
        .function-icon {
            width: 40px;
            height: 40px;
            border-radius: 6px;
            background-color: rgba(44, 125, 160, 0.1);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 0.75rem;
            color: var(--primary-color);
            font-size: 1.2rem;
        }
        
        .function-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text-color);
        }
        
        .function-desc {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        /* Related Tools */
        .related-tools {
            background-color: white;
            border-radius: 8px;
            border: 1px solid var(--border-color); 
            margin-bottom: 1.5rem;
        }
        
        .related-title {
            font-weight: 600;
            margin-bottom: 1.25rem;
            padding-bottom: 0.75rem; 
            color: var(--primary-color);
        }
        
        .related-tool {
            display: flex;
            align-items: center;
            padding: 0.75rem 0;
            border-bottom: 1px solid var(--border-color);
            transition: background-color 0.3s;
        }
        
        .related-tool:hover {
            background-color: var(--light-gray);
        }
        
        .related-tool:last-child {
            border-bottom: none;
        }
        
        .related-icon {
            width: 36px;
            height: 36px;
            border-radius: 6px;
            background-color: rgba(44, 125, 160, 0.1);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 1rem;
            color: var(--primary-color);
        }
        
        .related-name {
            font-weight: 500;
            margin-bottom: 0.25rem;
        }
        
        .related-desc {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        /* Ad Container */
        .ad-container {
            background-color: var(--light-gray);
            border-radius: 8px;
            padding: 1.5rem;
            margin-bottom: 1.5rem;
            text-align: center;
            border: 1px solid var(--border-color);
        }
        
        .ad-label {
            font-size: 0.75rem;
            color: var(--text-muted);
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 0.5rem;
        }
        
        .ad-placeholder {
            width: 100%;
            height: 250px;
            background-color: #f0f4f8;
            border: 1px dashed #dee2e6;
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-muted);
            font-weight: 500;
        }
        
        /* Footer */
        .footer {
            background-color: var(--light-gray); 
            margin-top: 3rem;
            border-top: 1px solid var(--border-color);
        }
        
        /* Responsive */
        @media (max-width: 768px) {
            .tool-card {
                padding: 1.5rem;
            }
            
            .multimeter-controls {
                grid-template-columns: 1fr;
            }
            
            .multimeter-reading {
                font-size: 2rem;
            }
        }
        
        /* Toast notifications */
        .toast-container {
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1050;
            max-width: 350px;
        }
        
        /* Tab styling for different multimeter sections */
        .tab-container {
            margin-bottom: 1.5rem;
        }
        
        .nav-tabs {
            border-bottom: 1px solid var(--border-color);
        }
        
        .nav-tabs .nav-link {
            border: none;
            color: var(--text-muted);
            font-weight: 500;
        }
        
        .nav-tabs .nav-link.active {
            color: var(--primary-color);
            border-bottom: 2px solid var(--primary-color);
            background-color: transparent;
        }
        
        .tab-content {
            padding: 1.5rem 0;
        }
        
        .connection-status {
            display: flex;
            align-items: center;
            margin-top: 0.5rem;
            font-size: 0.9rem;
        }
        
        .status-indicator {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            margin-right: 0.5rem;
        }
        
        .status-connected {
            background-color: var(--multimeter-green);
        }
        
        .status-disconnected {
            background-color: var(--multimeter-red);
        }
        
        /* Pulse animation for probe wire when not connected */
        @keyframes pulse-warning {
            0% { box-shadow: 0 0 0 0 rgba(220, 53, 69, 0.4); }
            70% { box-shadow: 0 0 0 10px rgba(220, 53, 69, 0); }
            100% { box-shadow: 0 0 0 0 rgba(220, 53, 69, 0); }
        }
        
        .probe-wire:not(.connected) {
            animation: pulse-warning 2s infinite;
        }
        
        /* Connection guide */
        .connection-guide {
            background-color: rgba(44, 125, 160, 0.05);
            border-radius: 6px;
            padding: 1rem;
            margin-top: 1rem;
            border-left: 3px solid var(--primary-color);
        }
        
        .action-buttons {
            display: flex;
            gap: 0.5rem;
        }
        
        .action-btn {
            padding: 0.5rem 1rem;
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            cursor: pointer;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        .action-btn:hover {
            background-color: #f8f9fa;
        }