:root {
            --accent-color: #2a4d8f;
            --light-gray: #f8f9fa;
            --border-color: #eaeaea;
            --text-color: #333;
            --text-muted: #6c757d;
            --success-color: #28a745;
            --warning-color: #ffc107;
            --danger-color: #dc3545;
            --clue-color: #e9f5ff;
            --cell-highlight: #fff9e6;
            --cell-error: #ffe6e6;
            --cell-correct: #e6ffe6;
        }
     
        .page-header {
            background: linear-gradient(135deg, rgba(197, 213, 234, 0.4) 0%, rgba(74, 111, 165, 0.4) 100%);
            padding: 1.5rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid rgba(74, 111, 165, 0.2);
            position: relative;
            overflow: hidden;    color: var(--text-color);
        }
       
        
        .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);
        } 
        .game-area {
            display: flex;
            flex-direction: column;
            align-items: center;
            margin: 2rem 0;
        }
        
        .crossnumber-container {
            width: 100%;
            max-width: 900px;
            background-color: white;
            border-radius: 10px;
            position: relative;
            overflow: hidden;
            margin-bottom: 2rem;
            border: 1px solid var(--border-color);
            padding: 20px;
        }
        
        .crossnumber-grid {
            display: grid;
            grid-template-columns: 50px repeat(12, 1fr);
            grid-template-rows: 50px repeat(12, 1fr);
            gap: 1px;
            margin: 0 auto;
            background-color: #ddd;
            border: 2px solid #333;
            max-width: 700px;
            width: 100%;
        }
        
        .grid-header {
            display: flex;
            align-items: center;
            justify-content: center;
            background-color: #f1f1f1;
            font-weight: bold;
            font-size: 1.2rem;
            color: #333;
        }
        
        .grid-cell {
            aspect-ratio: 1/1;
            background-color: white;
            display: flex;
            align-items: center;
            justify-content: center;
            position: relative;
            border: 1px solid #ccc;
            font-weight: 600;
            font-size: 1.2rem;
            transition: all 0.2s;
        }
        
        .grid-cell.black {
            background-color: #333;
            border-color: #333;
        }
        
        .grid-cell.selected {
            background-color: var(--cell-highlight);
            box-shadow: inset 0 0 0 2px var(--warning-color);
        }
        
        .grid-cell.error {
            background-color: var(--cell-error);
        }
        
        .grid-cell.correct {
            background-color: var(--cell-correct);
        }
        
        .cell-number {
            position: absolute;
            top: 2px;
            left: 2px;
            font-size: 0.7rem;
            color: var(--primary-color);
            font-weight: bold;
        }
        
        .cell-input {
            width: 100%;
            height: 100%;
            border: none;
            text-align: center;
            font-size: 1.2rem;
            font-weight: 600;
            background: transparent;
            color: #333;
            outline: none;
            caret-color: var(--primary-color);
        }
        
        .cell-input:focus {
            background-color: rgba(74, 111, 165, 0.05);
        }
        
        .clues-container {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 2rem;
            margin-top: 2rem;
        }
        
        .clue-section {
            background-color: var(--clue-color);
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
        }
        
        .clue-section h3 {
            color: var(--primary-color);
            font-weight: 600;
            margin-bottom: 1.25rem;
            padding-bottom: 0.75rem;
            border-bottom: 1px solid rgba(74, 111, 165, 0.3);
        }
        
        .clue-list {
            display: flex;
            flex-direction: column;
            gap: 0.75rem;
            max-height: 400px;
            overflow-y: auto;
        }
        
        .clue-item {
            padding: 0.75rem;
            background-color: white;
            border-radius: 6px;
            border-left: 3px solid var(--primary-color);
            transition: all 0.2s;
        }
        
        .clue-item:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }
        
        .clue-item.selected {
            background-color: var(--cell-highlight);
            border-left-color: var(--warning-color);
        }
        
        .clue-item.solved {
            background-color: rgba(40, 167, 69, 0.1);
            border-left-color: var(--success-color);
        }
        
        .clue-number {
            display: inline-block;
            font-weight: bold;
            color: var(--primary-color);
            margin-right: 0.5rem;
            min-width: 25px;
        }
        
        .clue-text {
            color: var(--text-color);
        }
        
        .game-controls {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .game-btn {
            padding: 0.75rem 1.5rem;
            border-radius: 6px;
            font-weight: 600;
            transition: all 0.3s;
            border: none;
        }
        
        .game-btn-primary {
            background-color: var(--primary-color);
            color: white;
        }
        
        .game-btn-primary:hover {
            background-color: var(--accent-color);
            transform: translateY(-2px);
        }
        
        .game-btn-secondary {
            background-color: #6c757d;
            color: white;
        }
        
        .game-btn-secondary:hover {
            background-color: #5a6268;
            transform: translateY(-2px);
        }
        
        .game-btn-success {
            background-color: var(--success-color);
            color: white;
        }
        
        .game-btn-success:hover {
            background-color: #218838;
            transform: translateY(-2px);
        }
        
        .game-stats {
            display: flex;
            justify-content: space-around;
            background-color: var(--light-gray);
            border-radius: 8px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            border: 1px solid var(--border-color);
        }
        
        .stat-item {
            text-align: center;
        }
        
        .stat-value {
            font-size: 2rem;
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: 0.25rem;
        }
        
        .stat-label {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        .game-info-box {
            background-color: rgba(74, 111, 165, 0.05);
            border-left: 3px solid var(--primary-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .game-tip-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;
        }
        
        .level-selection {
            display: flex;
            flex-wrap: wrap;
            gap: 0.75rem;
            margin: 1.5rem 0;
        }
        
        .level-btn {
            padding: 0.75rem 1.5rem;
            border-radius: 6px;
            font-weight: 600;
            background-color: white;
            border: 2px solid var(--border-color);
            transition: all 0.3s;
        }
        
        .level-btn:hover {
            background-color: var(--light-gray);
        }
        
        .level-btn.active {
            background-color: var(--primary-color);
            color: white;
            border-color: var(--primary-color);
        }
        
        .victory-message {
            background: linear-gradient(135deg, rgba(40, 167, 69, 0.1) 0%, rgba(40, 167, 69, 0.3) 100%);
            border: 2px solid var(--success-color);
            border-radius: 8px;
            padding: 2rem;
            text-align: center;
            margin: 2rem 0;
            display: none;
        }
        
        .victory-title {
            font-size: 2rem;
            font-weight: 700;
            color: var(--success-color);
            margin-bottom: 1rem;
        }
         
        .difficulty-indicator {
            display: inline-block;
            padding: 0.25rem 0.75rem;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 500;
            margin-right: 0.5rem;
        }
        
        .difficulty-easy {
            background-color: rgba(40, 167, 69, 0.1);
            color: #28a745;
        }
        
        .difficulty-medium {
            background-color: rgba(255, 193, 7, 0.1);
            color: #ffc107;
        }
        
        .difficulty-hard {
            background-color: rgba(220, 53, 69, 0.1);
            color: #dc3545;
        }
        
        .section-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
            padding-bottom: 0.5rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .strategy-tips {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .tip-card {
            background: white;
            border-radius: 8px;
            padding: 1.25rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
        
        .tip-icon {
            width: 48px;
            height: 48px;
            border-radius: 8px;
            background-color: rgba(74, 111, 165, 0.1);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1rem;
            color: var(--primary-color);
            font-size: 1.25rem;
        }
        
        .tip-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text-color);
        }
        
        .tip-desc {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        .game-mode-toggle {
            display: flex;
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 4px;
            margin-bottom: 1.5rem;
        }
        
        .mode-btn {
            flex: 1;
            text-align: center;
            padding: 0.75rem;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
        }
        
        .mode-btn.active {
            background-color: var(--primary-color);
            color: white;
        }
        
        .number-pad {
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: 0.5rem;
            margin: 1.5rem auto;
            max-width: 400px;
        }
        
        .num-btn {
            aspect-ratio: 1/1;
            border-radius: 8px;
            background-color: white;
            border: 2px solid var(--border-color);
            font-size: 1.5rem;
            font-weight: bold;
            color: var(--text-color);
            transition: all 0.2s;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .num-btn:hover {
            background-color: var(--light-gray);
            transform: translateY(-2px);
        }
        
        .num-btn.zero {
            grid-column: span 2;
            aspect-ratio: 2/1;
        }
        
        .num-btn.clear {
            background-color: var(--danger-color);
            color: white;
            border-color: var(--danger-color);
        }
        
        .puzzle-info {
            background-color: rgba(108, 117, 125, 0.05);
            border-left: 3px solid #6c757d;
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
            font-family: monospace;
            font-size: 0.9rem;
            line-height: 1.6;
        }
        
        .progress-container {
            margin: 1.5rem 0;
        }
        
        .progress-bar {
            height: 10px;
            border-radius: 5px;
            background-color: #e9ecef;
            overflow: hidden;
        }
        
        .progress-fill {
            height: 100%;
            background-color: var(--primary-color);
            transition: width 0.3s;
        }
        
        .progress-label {
            display: flex;
            justify-content: space-between;
            margin-bottom: 0.5rem;
        }
        
        @media (max-width: 768px) {
            .tool-card {
                padding: 1.5rem;
            }
            
            .crossnumber-grid {
                grid-template-columns: 40px repeat(8, 1fr);
                grid-template-rows: 40px repeat(8, 1fr);
            }
            
            .cell-number {
                font-size: 0.6rem;
            }
            
            .cell-input {
                font-size: 1rem;
            }
            
            .clues-container {
                grid-template-columns: 1fr;
            }
            
            .game-controls {
                flex-direction: column;
                align-items: center;
            }
            
            .game-btn {
                width: 100%;
                max-width: 300px;
            }
            
            .game-stats {
                flex-direction: column;
                gap: 1rem;
            }
        }
        
        @media (max-width: 480px) {
            .crossnumber-grid {
                grid-template-columns: 35px repeat(6, 1fr);
                grid-template-rows: 35px repeat(6, 1fr);
            }
            
            .cell-number {
                font-size: 0.5rem;
            }
            
            .cell-input {
                font-size: 0.9rem;
            }
            
            .number-pad {
                grid-template-columns: repeat(3, 1fr);
                gap: 0.3rem;
            }
            
            .num-btn {
                font-size: 1.2rem;
            }
        }
        
        .toast-container {
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1050;
        }
        
        @keyframes pulse {
            0% { transform: scale(1); }
            50% { transform: scale(1.1); }
            100% { transform: scale(1); }
        }
        
        .pulse {
            animation: pulse 0.5s ease;
        }
        
        .form-control {
            border: 1px solid #ddd;
            border-radius: 6px;
            padding: 0.75rem;
            transition: all 0.3s;
        }
        
        .form-control:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(74, 111, 165, 0.15);
        }
        
        .btn {
            border-radius: 6px;
            padding: 0.75rem 1.5rem;
            font-weight: 600;
            transition: all 0.3s;
        }
        
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
        }
        
        .btn-primary:hover {
            background-color: var(--accent-color);
            border-color: var(--accent-color);
            transform: translateY(-1px);
        }
        
        .btn-outline-primary {
            color: var(--primary-color);
            border-color: var(--primary-color);
        }
        
        .btn-outline-primary:hover {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            color: white;
        }
        
        .btn-outline-secondary {
            color: #6c757d;
            border-color: #6c757d;
        }
        
        .btn-outline-secondary:hover {
            background-color: #6c757d;
            border-color: #6c757d;
            color: white;
        }
        
        .alert {
            border-radius: 6px;
            border: 1px solid transparent;
            padding: 1rem;
            margin-bottom: 1rem;
        }
        
        .alert-success {
            background-color: rgba(40, 167, 69, 0.1);
            border-color: rgba(40, 167, 69, 0.2);
            color: #155724;
        }
        
        .alert-info {
            background-color: rgba(23, 162, 184, 0.1);
            border-color: rgba(23, 162, 184, 0.2);
            color: #0c5460;
        }
        
        .alert-warning {
            background-color: rgba(255, 193, 7, 0.1);
            border-color: rgba(255, 193, 7, 0.2);
            color: #856404;
        }
        
        .alert-danger {
            background-color: rgba(220, 53, 69, 0.1);
            border-color: rgba(220, 53, 69, 0.2);
            color: #721c24;
        }
        
        hr {
            border: 0;
            border-top: 1px solid var(--border-color);
            margin: 1.5rem 0;
        }
        
        .text-muted {
            color: var(--text-muted) !important;
        }
        
        .text-success {
            color: var(--success-color) !important;
        }
        
        .text-warning {
            color: var(--warning-color) !important;
        }
        
        .text-danger {
            color: var(--danger-color) !important;
        }
        
        .text-primary {
            color: var(--primary-color) !important;
        }
        
        .table {
            width: 100%;
            margin-bottom: 1rem;
            color: var(--text-color);
        }
        
        .table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .table-striped tbody tr:nth-of-type(odd) {
            background-color: rgba(0, 0, 0, 0.02);
        }
        
        .table-bordered {
            border: 1px solid var(--border-color);
        }
        
        .table-bordered th,
        .table-bordered td {
            border: 1px solid var(--border-color);
        }
        
        .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;
        }
        
        .step-content {
            flex: 1;
        }
        
        .faq-section {
            margin-top: 2rem;
        }
        
        .accordion-button:not(.collapsed) {
            background-color: rgba(74, 111, 165, 0.1);
            color: var(--primary-color);
            font-weight: 600;
        }
        
        .accordion-button:focus {
            box-shadow: 0 0 0 3px rgba(74, 111, 165, 0.25);
            border-color: var(--primary-color);
        }
        
        .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);
        }
        
        .social-icons {
            display: flex;
            gap: 0.75rem;
            margin-top: 1rem;
        }
        
        .social-icon {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background-color: var(--light-gray);
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-muted);
            text-decoration: none;
            transition: all 0.3s;
        }
        
        .social-icon:hover {
            background-color: var(--primary-color);
            color: white;
            transform: translateY(-3px);
        }
        
        .save-load-container {
            display: flex;
            gap: 1rem;
            margin: 1.5rem 0;
            flex-wrap: wrap;
        }
        
        .generator-options {
            background-color: var(--light-gray);
            border-radius: 8px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            border: 1px solid var(--border-color);
        }
        
        .generator-controls {
            display: flex;
            gap: 1rem;
            margin-top: 1rem;
            flex-wrap: wrap;
        }
        
        .puzzle-id {
            font-family: monospace;
            background-color: rgba(0,0,0,0.05);
            padding: 0.25rem 0.5rem;
            border-radius: 4px;
            font-size: 0.9rem;
        }
        
        .pencil-marks {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            grid-template-rows: repeat(3, 1fr);
            font-size: 0.5rem;
            color: #888;
            pointer-events: none;
            padding: 1px;
        }
        
        .pencil-mark {
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .print-container {
            display: none;
        }
        
        @media print {
            .navbar, .page-header, .game-controls, .level-selection, .clues-container, .footer, .ad-container, .related-tools, .number-pad {
                display: none !important;
            }
            
            .print-container {
                display: block;
            }
            
            .tool-card {
                box-shadow: none;
                border: 1px solid #000;
            }
            
            .crossnumber-container {
                border: 2px solid #000;
            }
            
            .grid-cell {
                border: 1px solid #000;
            }
            
            .grid-cell.black {
                background-color: #000 !important;
                -webkit-print-color-adjust: exact;
                print-color-adjust: exact;
            }
        }