* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        :root {
            --primary-color: #4a6fa5;
            --secondary-color: #6e9cd2;
            --accent-color: #ff9e40;
            --light-color: #f8f9fa;
            --dark-color: #343a40;
            --gray-color: #6c757d;
            --success-color: #28a745;
            --danger-color: #dc3545;
            --border-radius: 8px;
            --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
            --card-width: 100px;
            --card-height: 120px;
        }

        body {
            background-color: #f5f7fa;
            color: #333;
            line-height: 1.6;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* Header Styles */
        header {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            padding: 1rem 2rem;
            box-shadow: var(--box-shadow);
            position: relative;
        }

        .header-container {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            display: flex;
            align-items: center;
        }

        .logo i {
            margin-right: 10px;
            color: var(--accent-color);
        }

        .nav-desktop {
            display: flex;
        }

        .nav-desktop a {
            color: white;
            text-decoration: none;
            margin-left: 1.5rem;
            font-weight: 500;
            transition: color 0.3s;
        }

        .nav-desktop a:hover {
            color: var(--accent-color);
        }

        .mobile-toggle {
            display: none;
            font-size: 1.5rem;
            background: none;
            border: none;
            color: white;
            cursor: pointer;
        }

        .nav-mobile {
            display: none;
            flex-direction: column;
            background-color: var(--primary-color);
            position: absolute;
            top: 100%;
            left: 0;
            right: 0;
            padding: 1rem;
            box-shadow: var(--box-shadow);
            z-index: 1000;
        }

        .nav-mobile.active {
            display: flex;
        }

        .nav-mobile a {
            color: white;
            text-decoration: none;
            padding: 0.8rem 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            display: flex;
            align-items: center;
        }

        .nav-mobile a i {
            margin-right: 10px;
            width: 20px;
        }

        /* Main Content */
        main {
            flex: 1;
            padding: 2rem;
            max-width: 1200px;
            margin: 0 auto;
            width: 100%;
        }

        .page-title {
            text-align: center;
            margin-bottom: 2rem;
            color: var(--primary-color);
        }

        .game-info {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
            gap: 1rem;
        }

        .stats {
            display: flex;
            gap: 1.5rem;
        }

        .stat {
            background: white;
            padding: 0.8rem 1.2rem;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            display: flex;
            flex-direction: column;
            align-items: center;
            min-width: 80px;
        }

        .stat-value {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary-color);
        }

        .stat-label {
            font-size: 0.9rem;
            color: var(--gray-color);
        }

        .controls {
            display: flex;
            gap: 1rem;
        }

        .btn {
            padding: 0.8rem 1.5rem;
            border: none;
            border-radius: var(--border-radius);
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .btn-primary {
            background-color: var(--primary-color);
            color: white;
        }

        .btn-primary:hover {
            background-color: var(--secondary-color);
            transform: translateY(-2px);
        }

        .btn-secondary {
            background-color: var(--light-color);
            color: var(--dark-color);
            border: 1px solid #ddd;
        }

        .btn-secondary:hover {
            background-color: #e9ecef;
            transform: translateY(-2px);
        }

        .game-container {
            background: white;
            border-radius: var(--border-radius);
            padding: 2rem;
            box-shadow: var(--box-shadow);
            margin-bottom: 2rem;
            display: flex;
            justify-content: center;
        }

        .cards-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1rem;
            max-width: calc(var(--card-width) * 4 + 3rem);
        }

        .card {
            width: var(--card-width);
            height: var(--card-height);
            perspective: 1000px;
            cursor: pointer;
        }

        .card-inner {
            position: relative;
            width: 100%;
            height: 100%;
            text-align: center;
            transition: transform 0.6s;
            transform-style: preserve-3d;
        }

        .card.flipped .card-inner {
            transform: rotateY(180deg);
        }

        .card.matched .card-back {
            background-color: #e8f5e9;
            border-color: var(--success-color);
        }

        .card-front, .card-back {
            position: absolute;
            width: 100%;
            height: 100%;
            -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
            display: flex;
            justify-content: center;
            align-items: center;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
        }

        .card-front {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            font-size: 2rem;
        }

        .card-back {
            background-color: white;
            border: 2px solid var(--primary-color);
            transform: rotateY(180deg);
            font-size: 2.5rem;
            color: var(--primary-color);
        }

        .win-message {
            text-align: center;
            margin-top: 2rem;
            padding: 1.5rem;
            background-color: #e8f5e9;
            border-radius: var(--border-radius);
            border: 1px solid var(--success-color);
            color: var(--success-color);
            font-weight: 600;
            display: none;
        }

        .win-message.show {
            display: block;
            animation: fadeIn 0.5s;
        }

        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        .history-container {
            background: white;
            border-radius: var(--border-radius);
            padding: 2rem;
            box-shadow: var(--box-shadow);
            margin-bottom: 2rem;
        }

        .history-title {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1.5rem;
            padding-bottom: 0.8rem;
            border-bottom: 2px solid var(--light-color);
            flex-wrap: wrap;
            gap: 1rem;
        }

        .history-list {
            max-height: 300px;
            overflow-y: auto;
        }

        .history-item {
            display: flex;
            justify-content: space-between;
            padding: 1rem 0;
            border-bottom: 1px solid #eee;
            align-items: center;
        }

        .history-item:last-child {
            border-bottom: none;
        }

        .history-timestamp {
            color: var(--gray-color);
            font-size: 0.9rem;
        }

        .history-result {
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .history-win {
            color: var(--success-color);
        }

        .seo-section {
            background: white;
            border-radius: var(--border-radius);
            padding: 2rem;
            box-shadow: var(--box-shadow);
            margin-bottom: 2rem;
        }

        .seo-section h2 {
            color: var(--primary-color);
            margin-bottom: 1rem;
        }

        .seo-section p {
            margin-bottom: 1rem;
            line-height: 1.8;
        }

        .seo-section ul {
            margin-left: 2rem;
            margin-bottom: 1rem;
        }

        .seo-section li {
            margin-bottom: 0.8rem;
            line-height: 1.6;
        }

        /* Footer Styles */
        footer {
            background-color: var(--dark-color);
            color: white;
            padding: 3rem 2rem 1.5rem;
            margin-top: 2rem;
        }

        .footer-container {
            max-width: 1200px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 2rem;
        }

        .footer-section h3 {
            font-size: 1.2rem;
            margin-bottom: 1.2rem;
            color: var(--accent-color);
        }

        .footer-links {
            list-style: none;
        }

        .footer-links li {
            margin-bottom: 0.8rem;
        }

        .footer-links a {
            color: #ddd;
            text-decoration: none;
            transition: color 0.3s;
            display: flex;
            align-items: center;
        }

        .footer-links a i {
            margin-right: 8px;
            width: 20px;
        }

        .footer-links a:hover {
            color: var(--accent-color);
        }

        .copyright {
            text-align: center;
            margin-top: 3rem;
            padding-top: 1.5rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            color: #aaa;
            font-size: 0.9rem;
        }
        .icon-small {
            width: 60px;
            height: 60px;
            border-radius: 8px;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .header-container {
                padding: 0;
            }

            .nav-desktop {
                display: none;
            }

            .mobile-toggle {
                display: block;
            }

            .game-info {
                flex-direction: column;
                align-items: stretch;
            }

            .stats {
                justify-content: space-around;
            }

            .controls {
                justify-content: center;
            }

            .cards-grid {
                grid-template-columns: repeat(3, 1fr);
                max-width: calc(var(--card-width) * 3 + 2rem);
            }

            :root {
                --card-width: 90px;
                --card-height: 110px;
            }
        }

        @media (max-width: 480px) {
            header {
                padding: 1rem;
            }
            
            .logo {
                font-size: 1.5rem;
            }

            .cards-grid {
                grid-template-columns: repeat(2, 1fr);
                max-width: calc(var(--card-width) * 2 + 1rem);
            }

            :root {
                --card-width: 80px;
                --card-height: 100px;
            }
            
            main {
                padding: 1rem;
            }
            
            .game-container, .history-container, .seo-section {
                padding: 1.5rem;
            }

            .card-back, .card-front {
                font-size: 2rem;
            }

            .history-item {
                flex-direction: column;
                align-items: flex-start;
                gap: 0.5rem;
            }

            .history-timestamp {
                margin-left: 1.7rem;
            }
        }