:root {
            --primary-color: #4a6fa5;
            --primary-light: #6b8cc6;
            --primary-dark: #2a4a7a;
            --secondary-color: #a9d6e5;
            --accent-color: #ff7e5f;
            --accent-light: #ff9e87;
            --light-gray: #f8f9fa;
            --medium-gray: #e9ecef;
            --dark-gray: #495057;
            --border-color: #dee2e6;
            --text-color: #2d3748;
            --text-muted: #6c757d;
            --success-color: #28a745;
            --warning-color: #ffc107;
            --danger-color: #dc3545;
            --cell-border: #cbd5e0;
            --cell-bg: #ffffff;
            --line-color: #4a6fa5;
            --line-hover: #6b8cc6;
            --line-highlight: #ff7e5f;
            --number-cell: #edf2f7;
            --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
            --shadow-md: 0 4px 8px rgba(0,0,0,0.08);
            --shadow-lg: 0 8px 16px rgba(0,0,0,0.1);
            --transition-fast: 0.15s ease;
            --transition-normal: 0.3s ease;
            --transition-slow: 0.5s ease;
        }
         
        .page-header {
            background: linear-gradient(135deg, rgba(169, 214, 229, 0.15) 0%, rgba(74, 111, 165, 0.15) 100%);
            padding: 2rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid rgba(74, 111, 165, 0.1);
            position: relative;
            overflow: hidden;    color: var(--text-color); 
        }
        
        .page-header::before {
            content: "";
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background-image: 
                radial-gradient(circle at 25% 25%, rgba(74, 111, 165, 0.03) 1px, transparent 1px),
                radial-gradient(circle at 75% 75%, rgba(169, 214, 229, 0.03) 1px, transparent 1px);
            background-size: 40px 40px, 50px 50px;
            opacity: 0.7;
            transform: rotate(15deg);
        }
        
        .breadcrumb {
            background-color: transparent;
            padding: 0.5rem 0;
            margin-bottom: 0.5rem;
        }
        
        .breadcrumb-item a {
            color: var(--text-muted);
            text-decoration: none;
            transition: color var(--transition-fast);
        }
        
        .breadcrumb-item a:hover {
            color: var(--primary-color);
        }
        
        .breadcrumb-item.active {
            color: var(--primary-color);
            font-weight: 500;
        }
        
        .tool-card {
            background: white;
            border-radius: 12px;
            border: 1px solid var(--border-color);
            padding: 2rem;
            margin-bottom: 1.5rem;
            box-shadow: var(--shadow-sm);
            transition: box-shadow var(--transition-normal);
        }
        
        .tool-card:hover {
            box-shadow: var(--shadow-md);
        }
        
        .tool-header {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 25px;
        }
        
        .tool-header h2 {
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
            position: relative;
            display: inline-block;
        }
        
        .tool-header h2::after {
            content: '';
            position: absolute;
            bottom: -10px;
            left: 0;
            width: 60px;
            height: 4px;
            background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
            border-radius: 2px;
        }
        
        .game-area {
            display: flex;
            flex-direction: column;
            align-items: center;
            margin: 2rem 0;
        }
        
        .puzzle-container {
            width: 100%;
            max-width: 700px;
            background-color: white;
            border-radius: 12px;
            position: relative;
            overflow: hidden;
            margin-bottom: 2rem;
            border: 1px solid var(--border-color);
            padding: 25px;
            box-shadow: var(--shadow-md);
        }
        
        .puzzle-grid {
            display: grid;
            gap: 0;
            margin: 0 auto;
            background-color: white;
            border: 2px solid var(--cell-border);
            border-radius: 4px;
            position: relative;
            box-shadow: inset 0 0 8px rgba(0,0,0,0.05);
        }
        
        .puzzle-cell {
            border: 1px solid var(--cell-border);
            background-color: var(--cell-bg);
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            user-select: none;
            transition: background-color var(--transition-fast);
        }
        
        .puzzle-cell.number-cell {
            background-color: var(--number-cell);
            font-weight: 700;
            font-size: 1.3rem;
            color: var(--primary-color);
            position: relative;
            z-index: 2;
            box-shadow: inset 0 0 0 2px rgba(74, 111, 165, 0.2);
        }
        
        .puzzle-cell.number-cell::before {
            content: '';
            position: absolute;
            top: 2px;
            left: 2px;
            right: 2px;
            bottom: 2px;
            border: 2px solid rgba(74, 111, 165, 0.1);
            border-radius: 2px;
            z-index: -1;
        }
        
        .puzzle-cell.empty-cell {
            background-color: white;
        }
        
        .puzzle-cell:hover {
            background-color: rgba(74, 111, 165, 0.05);
        }
        
        .puzzle-cell.active {
            background-color: rgba(74, 111, 165, 0.1);
        }
        
        .line-horizontal {
            position: absolute;
            height: 8px;
            background-color: transparent;
            z-index: 2;
            transition: all var(--transition-normal);
            border-radius: 4px;
            cursor: pointer;
        }
        
        .line-horizontal.active {
            background-color: var(--line-color);
            box-shadow: 0 2px 4px rgba(74, 111, 165, 0.3);
        }
        
        .line-horizontal:hover:not(.active) {
            background-color: rgba(74, 111, 165, 0.2);
        }
        
        .line-horizontal.highlight {
            background-color: var(--line-highlight);
            box-shadow: 0 2px 8px rgba(255, 126, 95, 0.4);
            animation: pulse-highlight 1.5s infinite;
        }
        
        .line-vertical {
            position: absolute;
            width: 8px;
            background-color: transparent;
            z-index: 2;
            transition: all var(--transition-normal);
            border-radius: 4px;
            cursor: pointer;
        }
        
        .line-vertical.active {
            background-color: var(--line-color);
            box-shadow: 2px 0 4px rgba(74, 111, 165, 0.3);
        }
        
        .line-vertical:hover:not(.active) {
            background-color: rgba(74, 111, 165, 0.2);
        }
        
        .line-vertical.highlight {
            background-color: var(--line-highlight);
            box-shadow: 2px 0 8px rgba(255, 126, 95, 0.4);
            animation: pulse-highlight 1.5s infinite;
        }
        
        @keyframes pulse-highlight {
            0% { opacity: 1; }
            50% { opacity: 0.7; }
            100% { opacity: 1; }
        }
        
        .game-controls {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .game-btn {
            padding: 0.875rem 1.75rem;
            border-radius: 8px;
            font-weight: 600;
            transition: all var(--transition-normal);
            border: none;
            display: flex;
            align-items: center;
            justify-content: center;
            position: relative;
            overflow: hidden;
        }
        
        .game-btn::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 5px;
            height: 5px;
            background: rgba(255, 255, 255, 0.5);
            opacity: 0;
            border-radius: 100%;
            transform: scale(1, 1) translate(-50%, -50%);
            transform-origin: 50% 50%;
        }
        
        .game-btn:focus:not(:active)::after {
            animation: ripple 1s ease-out;
        }
        
        @keyframes ripple {
            0% {
                transform: scale(0, 0);
                opacity: 0.5;
            }
            100% {
                transform: scale(40, 40);
                opacity: 0;
            }
        }
        
        .game-btn-primary {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            box-shadow: 0 4px 12px rgba(74, 111, 165, 0.3);
        }
        
        .game-btn-primary:hover {
            background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(74, 111, 165, 0.4);
        }
        
        .game-btn-secondary {
            background: linear-gradient(135deg, #6c757d, #868e96);
            color: white;
            box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
        }
        
        .game-btn-secondary:hover {
            background: linear-gradient(135deg, #5a6268, #6c757d);
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(108, 117, 125, 0.4);
        }
        
        .game-btn-success {
            background: linear-gradient(135deg, var(--success-color), #34ce57);
            color: white;
            box-shadow: 0 4px 12px rgba(40, 167, 69, 0.3);
        }
        
        .game-btn-success:hover {
            background: linear-gradient(135deg, #218838, var(--success-color));
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(40, 167, 69, 0.4);
        }
        
        .game-stats {
            display: flex;
            justify-content: space-around;
            background: linear-gradient(135deg, #f8f9fa, #e9ecef);
            border-radius: 12px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            border: 1px solid var(--border-color);
            box-shadow: var(--shadow-sm);
        }
        
        .stat-item {
            text-align: center;
            position: relative;
            padding: 0 1rem;
        }
        
        .stat-item:not(:last-child)::after {
            content: '';
            position: absolute;
            right: 0;
            top: 20%;
            height: 60%;
            width: 1px;
            background: linear-gradient(to bottom, transparent, var(--border-color), transparent);
        }
        
        .stat-value {
            font-size: 2.2rem;
            font-weight: 800;
            color: var(--primary-color);
            margin-bottom: 0.25rem;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.05);
        }
        
        .stat-label {
            color: var(--text-muted);
            font-size: 0.9rem;
            font-weight: 500;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }
        
        .game-info-box {
            background: linear-gradient(135deg, rgba(74, 111, 165, 0.05), rgba(74, 111, 165, 0.1));
            border-left: 4px solid var(--primary-color);
            padding: 1.25rem;
            border-radius: 0 8px 8px 0;
            margin: 1.5rem 0;
            box-shadow: var(--shadow-sm);
        }
        
        .game-tip-box {
            background: linear-gradient(135deg, rgba(255, 193, 7, 0.05), rgba(255, 193, 7, 0.1));
            border-left: 4px solid var(--warning-color);
            padding: 1.25rem;
            border-radius: 0 8px 8px 0;
            margin: 1.5rem 0;
            box-shadow: var(--shadow-sm);
        }
        
        .level-selection {
            display: flex;
            flex-wrap: wrap;
            gap: 0.75rem;
            margin: 1.5rem 0;
        }
        
        .level-btn {
            padding: 0.875rem 1.5rem;
            border-radius: 8px;
            font-weight: 600;
            background-color: white;
            border: 2px solid var(--border-color);
            transition: all var(--transition-normal);
            flex: 1;
            min-width: 140px;
            text-align: center;
        }
        
        .level-btn:hover {
            background-color: var(--light-gray);
            transform: translateY(-2px);
            box-shadow: var(--shadow-sm);
        }
        
        .level-btn.active {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            border-color: transparent;
            box-shadow: 0 4px 12px rgba(74, 111, 165, 0.3);
        }
        
        .victory-message {
            background: linear-gradient(135deg, rgba(40, 167, 69, 0.1) 0%, rgba(40, 167, 69, 0.2) 100%);
            border: 2px solid var(--success-color);
            border-radius: 12px;
            padding: 2.5rem;
            text-align: center;
            margin: 2rem 0;
            display: none;
            animation: fadeIn 0.5s ease-out;
            box-shadow: var(--shadow-md);
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        .victory-title {
            font-size: 2.2rem;
            font-weight: 800;
            color: var(--success-color);
            margin-bottom: 1rem;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        
        .victory-title i {
            font-size: 2.5rem;
            filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1));
        }
         
        .difficulty-indicator {
            display: inline-block;
            padding: 0.3rem 0.9rem;
            border-radius: 20px;
            font-size: 0.8rem;
            font-weight: 600;
            margin-right: 0.5rem;
            letter-spacing: 0.5px;
        }
        
        .difficulty-easy {
            background-color: rgba(40, 167, 69, 0.15);
            color: var(--success-color);
            border: 1px solid rgba(40, 167, 69, 0.3);
        }
        
        .difficulty-medium {
            background-color: rgba(255, 193, 7, 0.15);
            color: var(--warning-color);
            border: 1px solid rgba(255, 193, 7, 0.3);
        }
        
        .difficulty-hard {
            background-color: rgba(220, 53, 69, 0.15);
            color: var(--danger-color);
            border: 1px solid rgba(220, 53, 69, 0.3);
        }
         
        .strategy-tips {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 1.25rem;
            margin: 1.5rem 0;
        }
        
        .tip-card {
            background: white;
            border-radius: 10px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-normal);
            position: relative;
            overflow: hidden;
        }
        
        .tip-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: linear-gradient(to bottom, var(--primary-color), var(--primary-light));
        }
        
        .tip-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }
        
        .tip-icon {
            width: 52px;
            height: 52px;
            border-radius: 12px;
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1.25rem;
            color: white;
            font-size: 1.3rem;
            box-shadow: 0 4px 8px rgba(74, 111, 165, 0.3);
        }
        
        .tip-title {
            font-weight: 700;
            margin-bottom: 0.75rem;
            color: var(--primary-color);
        }
        
        .tip-desc {
            color: var(--text-muted);
            font-size: 0.95rem;
            line-height: 1.6;
        }
        
        .drawing-mode-toggle {
            display: flex;
            background-color: var(--light-gray);
            border-radius: 10px;
            padding: 6px;
            margin-bottom: 1.5rem;
            border: 1px solid var(--border-color);
            box-shadow: var(--shadow-sm);
        }
        
        .mode-btn {
            flex: 1;
            text-align: center;
            padding: 0.875rem;
            border-radius: 8px;
            cursor: pointer;
            transition: all var(--transition-fast);
            font-weight: 600;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        
        .mode-btn.active {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            box-shadow: 0 4px 8px rgba(74, 111, 165, 0.3);
        }
        
        .mode-btn:not(.active):hover {
            background-color: white;
            transform: translateY(-1px);
        }
        
        .move-history {
            background-color: var(--light-gray);
            border-radius: 12px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            max-height: 300px;
            overflow-y: auto;
            border: 1px solid var(--border-color);
            box-shadow: var(--shadow-sm);
        }
        
        .move-history-title {
            font-weight: 700;
            margin-bottom: 1rem;
            color: var(--primary-color);
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        
        .move-list {
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }
        
        .move-item {
            padding: 0.75rem;
            background-color: white;
            border-radius: 6px;
            border-left: 4px solid var(--primary-color);
            font-family: 'JetBrains Mono', 'SF Mono', monospace;
            font-size: 0.9rem;
            transition: all var(--transition-fast);
        }
        
        .move-item:hover {
            transform: translateX(3px);
            box-shadow: var(--shadow-sm);
        }
        
        .move-item.current {
            background-color: rgba(74, 111, 165, 0.1);
            font-weight: bold;
            border-left: 4px solid var(--accent-color);
        }
        
        .slider-container {
            margin: 1.5rem 0;
        }
        
        .slider-label {
            display: flex;
            justify-content: space-between;
            margin-bottom: 0.75rem;
            font-weight: 600;
            color: var(--primary-color);
        }
        
        .form-range::-webkit-slider-thumb {
            background: var(--primary-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.2);
        }
        
        .form-range::-moz-range-thumb {
            background: var(--primary-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.2);
        }
        
        .form-range::-webkit-slider-runnable-track {
            background-color: var(--medium-gray);
        }
        
        .form-range::-moz-range-track {
            background-color: var(--medium-gray);
        }
        
        .grid-size-controls {
            display: flex;
            align-items: center;
            flex-wrap: wrap;
            gap: 1rem;
            margin: 1.5rem 0;
            background-color: var(--light-gray);
            padding: 1.25rem;
            border-radius: 10px;
            border: 1px solid var(--border-color);
        }
        
        .grid-size-btn {
            padding: 0.75rem 1.5rem;
            border-radius: 8px;
            background-color: white;
            border: 2px solid var(--border-color);
            transition: all var(--transition-normal);
            font-weight: 600;
            color: var(--text-color);
            flex: 1;
            text-align: center;
            min-width: 100px;
        }
        
        .grid-size-btn:hover {
            background-color: var(--light-gray);
            transform: translateY(-2px);
            box-shadow: var(--shadow-sm);
        }
        
        .grid-size-btn.active {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            border-color: transparent;
            box-shadow: 0 4px 12px rgba(74, 111, 165, 0.3);
        }
        
        .progress-container {
            width: 100%;
            height: 8px;
            background-color: var(--medium-gray);
            border-radius: 4px;
            overflow: hidden;
            margin: 1.5rem 0;
        }
        
        .progress-bar {
            height: 100%;
            background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
            width: 0%;
            transition: width 0.5s ease;
            border-radius: 4px;
        }
        
        .puzzle-rules {
            background: linear-gradient(135deg, rgba(255, 193, 7, 0.05), rgba(255, 193, 7, 0.1));
            border-left: 4px solid var(--warning-color);
            padding: 1.5rem;
            border-radius: 0 10px 10px 0;
            margin: 1.5rem 0;
            box-shadow: var(--shadow-sm);
        }
        
        .rule-item {
            display: flex;
            margin-bottom: 1rem;
            align-items: flex-start;
        }
        
        .rule-check {
            color: var(--success-color);
            margin-right: 0.75rem;
            margin-top: 0.2rem;
            font-size: 1.1rem;
        }
        
        @media (max-width: 768px) { 
            .puzzle-container {
                padding: 15px;
            }
            
            .game-controls {
                flex-direction: column;
                align-items: stretch;
            }
            
            .game-btn {
                width: 100%;
            }
            
            .game-stats {
                flex-direction: column;
                gap: 1.5rem;
                text-align: center;
            }
            
            .stat-item:not(:last-child)::after {
                display: none;
            }
            
            .stat-item {
                padding: 0;
            }
            
            .level-btn {
                min-width: 120px;
            }
            
            .grid-size-btn {
                min-width: 80px;
            }
        }
        
        @media (max-width: 480px) {
            .puzzle-cell {
                font-size: 0.9rem;
            }
            
            .stat-value {
                font-size: 1.8rem;
            }
            
            .victory-title {
                font-size: 1.8rem;
            }
            
            .level-selection {
                justify-content: center;
            }
            
            .level-btn {
                min-width: 100px;
                padding: 0.75rem 1rem;
            }
        }
        
        .toast-container {
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1050;
            max-width: 350px;
        }
        
        .custom-toast {
            background: white;
            border-radius: 10px;
            padding: 1rem 1.25rem;
            margin-bottom: 1rem;
            box-shadow: var(--shadow-lg);
            border-left: 4px solid var(--primary-color);
            animation: slideInRight 0.3s ease-out;
            display: flex;
            align-items: center;
            gap: 0.75rem;
        }
        
        .custom-toast.success {
            border-left-color: var(--success-color);
        }
        
        .custom-toast.error {
            border-left-color: var(--danger-color);
        }
        
        .custom-toast.warning {
            border-left-color: var(--warning-color);
        }
        
        .custom-toast.info {
            border-left-color: var(--primary-color);
        }
        
        @keyframes slideInRight {
            from { transform: translateX(100%); opacity: 0; }
            to { transform: translateX(0); opacity: 1; }
        }
        
        @keyframes pulse {
            0% { transform: scale(1); }
            50% { transform: scale(1.05); }
            100% { transform: scale(1); }
        }
        
        .pulse {
            animation: pulse 0.5s ease;
        }
        
    
        .alert {
            border-radius: 10px;
            border: 1px solid transparent;
            padding: 1.25rem;
            margin-bottom: 1rem;
        }
        
        .alert-success {
            background: linear-gradient(135deg, rgba(40, 167, 69, 0.1), rgba(40, 167, 69, 0.15));
            border-color: rgba(40, 167, 69, 0.2);
            color: #155724;
        }
        
        .alert-info {
            background: linear-gradient(135deg, rgba(23, 162, 184, 0.1), rgba(23, 162, 184, 0.15));
            border-color: rgba(23, 162, 184, 0.2);
            color: #0c5460;
        }
        
        .alert-warning {
            background: linear-gradient(135deg, rgba(255, 193, 7, 0.1), rgba(255, 193, 7, 0.15));
            border-color: rgba(255, 193, 7, 0.2);
            color: #856404;
        }
        
        .alert-danger {
            background: linear-gradient(135deg, rgba(220, 53, 69, 0.1), rgba(220, 53, 69, 0.15));
            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);
            border-radius: 8px;
            overflow: hidden;
            box-shadow: var(--shadow-sm);
        }
        
        .table th {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            font-weight: 600;
            border: none;
            padding: 1rem;
        }
        
        .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: 1.75rem;
            align-items: flex-start;
            background-color: white;
            border-radius: 10px;
            padding: 1.25rem;
            border-left: 4px solid var(--primary-color);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-normal);
        }
        
        .usage-step:hover {
            transform: translateX(5px);
            box-shadow: var(--shadow-md);
        }
        
        .step-number {
            width: 32px;
            height: 32px;
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 1.25rem;
            flex-shrink: 0;
            font-weight: 700;
            font-size: 1rem;
            box-shadow: 0 4px 8px rgba(74, 111, 165, 0.3);
        }
        
        .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: 700;
            box-shadow: none;
        }
        
        .accordion-button:focus {
            box-shadow: 0 0 0 3px rgba(74, 111, 165, 0.25);
            border-color: var(--primary-color);
        }
        
        .accordion-button::after {
            background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%234a6fa5'%3e%3cpath fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/%3e%3c/svg%3e");
        }
        
        .action-btn {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 0.75rem 1.25rem;
            margin-left: 0.5rem;
            transition: all var(--transition-normal);
            color: var(--text-color);
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            font-weight: 600;
        }
        
        .action-btn:hover {
            background-color: var(--light-gray);
            color: var(--primary-color);
            transform: translateY(-2px);
            box-shadow: var(--shadow-sm);
        }
        
        .social-icons {
            display: flex;
            gap: 0.75rem;
            margin-top: 1rem;
        }
        
        .social-icon {
            width: 40px;
            height: 40px;
            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 var(--transition-normal);
        }
        
        .social-icon:hover {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
            color: white;
            transform: translateY(-3px);
            box-shadow: 0 4px 8px rgba(74, 111, 165, 0.3);
        }
        
        .progress-indicator {
            display: flex;
            justify-content: space-between;
            margin: 1.5rem 0;
            position: relative;
        }
        
        .progress-indicator::before {
            content: '';
            position: absolute;
            top: 50%;
            left: 0;
            right: 0;
            height: 2px;
            background-color: var(--medium-gray);
            transform: translateY(-50%);
            z-index: 1;
        }
        
        .progress-step {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background-color: white;
            border: 2px solid var(--medium-gray);
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 600;
            color: var(--text-muted);
            position: relative;
            z-index: 2;
            transition: all var(--transition-normal);
        }
        
        .progress-step.active {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            color: white;
            box-shadow: 0 4px 8px rgba(74, 111, 165, 0.3);
        }
        
        .progress-step.completed {
            background-color: var(--success-color);
            border-color: var(--success-color);
            color: white;
        }
        
        .drag-instruction {
            text-align: center;
            padding: 1rem;
            background-color: rgba(74, 111, 165, 0.05);
            border-radius: 8px;
            margin: 1rem 0;
            font-size: 0.9rem;
            color: var(--text-muted);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        
        .keyboard-shortcuts {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .shortcut-item {
            display: flex;
            align-items: center;
            gap: 1rem;
            padding: 0.75rem;
            background-color: white;
            border-radius: 8px;
            border: 1px solid var(--border-color);
        }
        
        .shortcut-key {
            padding: 0.25rem 0.75rem;
            background-color: var(--light-gray);
            border-radius: 4px;
            font-family: monospace;
            font-weight: 600;
            color: var(--primary-color);
            border: 1px solid var(--border-color);
        }
        
        .completion-badge {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            padding: 0.5rem 1rem;
            background-color: rgba(40, 167, 69, 0.1);
            border-radius: 20px;
            color: var(--success-color);
            font-weight: 600;
            margin: 0.5rem 0;
        }