:root {
            --primary-color: #2c3e50;
            --secondary-color: #e74c3c;
            --background-color: #f5f6fa;
            --cell-color: #ffffff;
            --hover-color: #f8f9fa;
            --winning-color: #27ae60;
            --border-color: #dcdde1;
        }

        body {
            background-color: var(--background-color);
            color: var(--primary-color);
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 2rem 0;
        }

        .container {
            max-width: 800px;
            padding: 2rem;
        }

        .game-card {
            background: #ffffff;
            border-radius: 16px;
            padding: 2rem;
            margin-bottom: 2rem;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }

        h1 {
            color: var(--primary-color);
            font-weight: 700;
            margin-bottom: 2rem;
            font-size: 2.5rem;
        }

        .cell {
            width: 100px;
            height: 100px;
            border: 2px solid var(--border-color);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 3rem;
            cursor: pointer;
            background-color: var(--cell-color);
            border-radius: 12px;
            transition: all 0.2s ease;
        }

        .connect4-cell {
            width: 70px;
            height: 70px;
            border: 2px solid var(--border-color);
            border-radius: 50%;
            background-color: var(--cell-color);
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .cell:hover, .connect4-cell:hover {
            background-color: var(--hover-color);
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
        }

        .game-board {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 12px;
            max-width: 340px;
            margin: 30px auto;
            padding: 20px;
            background: #ffffff;
            border-radius: 16px;
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
        }

        .connect4-board {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 10px;
            max-width: 320px;
            margin: 30px auto;
            padding: 20px;
            background: #ffffff;
            border-radius: 16px;
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
        }

        .winning-cell {
            background-color: var(--winning-color) !important;
            color: white;
            animation: pulse 1s infinite;
        }

        @keyframes pulse {
            0% { transform: scale(1); }
            50% { transform: scale(1.02); }
            100% { transform: scale(1); }
        }

        #resetBtn, #resetConnect4Btn {
            background: var(--primary-color);
            border: none;
            padding: 12px 30px;
            border-radius: 8px;
            color: white;
            font-weight: 600;
            transition: all 0.2s ease;
            box-shadow: 0 4px 15px rgba(44, 62, 80, 0.2);
        }

        #resetBtn:hover, #resetConnect4Btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(44, 62, 80, 0.3);
            background: #34495e;
        }

        #message, #connect4Message {
            color: var(--primary-color);
            font-weight: 600;
            min-height: 2em;
            font-size: 1.5rem;
            margin-top: 1.5rem;
            padding: 15px;
            background: #ffffff;
            border-radius: 8px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
        }

        .cell[data-player="X"] {
            color: var(--primary-color);
        }

        .cell[data-player="O"] {
            color: var(--secondary-color);
        }

        .connect4-cell[data-player="red"] {
            background-color: var(--secondary-color);
        }

        .connect4-cell[data-player="yellow"] {
            background-color: #f1c40f;
        }

        .animate__animated {
            animation-duration: 0.3s;
        }

        @media (max-width: 768px) {
            .container {
                padding: 1rem;
            }
            
            .game-card {
                padding: 1.5rem;
            }
            
            .cell {
                width: 80px;
                height: 80px;
                font-size: 2.5rem;
            }
            
            .connect4-cell {
                width: 60px;
                height: 60px;
            }
            
            .game-board {
                max-width: 280px;
                gap: 8px;
            }
            
            .connect4-board {
                max-width: 260px;
                gap: 8px;
            }
            
            h1 {
                font-size: 2rem;
            }
        }