/* Reset and Base Styles */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            line-height: 1.6;
            color: #333;
            overflow-x: hidden;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* Navigation */
        .navbar {
            position: fixed;
            top: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid rgba(0, 0, 0, 0.1);
            z-index: 1000;
            transition: all 0.3s ease;
        }

        .nav-container {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 1rem 20px;
        }

        .nav-brand h2 {
            color: #6366f1;
            font-weight: 600;
        }

        .nav-links {
            display: flex;
            gap: 2rem;
        }

        .nav-links a {
            text-decoration: none;
            color: #333;
            font-weight: 500;
            transition: color 0.3s ease;
        }

        .nav-links a:hover {
            color: #6366f1;
        }

        /* Hero Section */
        .hero {
            min-height: 100vh;
            display: flex;
            align-items: center;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            position: relative;
            overflow: hidden;
        }

        .hero-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            display: grid;
            grid-template-columns: 1fr 1fr;
            align-items: center;
            gap: 4rem;
        }

        .hero-title {
            font-size: 3.5rem;
            font-weight: 700;
            line-height: 1.2;
            margin-bottom: 1.5rem;
        }

        .highlight {
            background: linear-gradient(45deg, #ffd700, #ffed4e);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hero-subtitle {
            font-size: 1.25rem;
            opacity: 0.9;
            margin-bottom: 2rem;
        }

        .hero-buttons {
            display: flex;
            gap: 1rem;
            flex-wrap: wrap;
        }

        .btn {
            padding: 1rem 2rem;
            border: none;
            border-radius: 50px;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
            text-align: center;
        }

        .btn-primary {
            background: #fff;
            color: #6366f1;
        }

        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
        }

        .btn-secondary {
            background: transparent;
            color: white;
            border: 2px solid rgba(255, 255, 255, 0.3);
        }

        .btn-secondary:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .floating-numbers {
            position: relative;
            width: 300px;
            height: 300px;
        }

        .floating-numbers span {
            position: absolute;
            font-size: 4rem;
            font-weight: 700;
            color: rgba(255, 255, 255, 0.1);
            animation: float 6s ease-in-out infinite;
        }

        .floating-numbers span:nth-child(1) { top: 10%; left: 20%; animation-delay: 0s; }
        .floating-numbers span:nth-child(2) { top: 20%; right: 10%; animation-delay: 1s; }
        .floating-numbers span:nth-child(3) { bottom: 30%; left: 10%; animation-delay: 2s; }
        .floating-numbers span:nth-child(4) { bottom: 10%; right: 20%; animation-delay: 3s; }
        .floating-numbers span:nth-child(5) { top: 50%; left: 50%; animation-delay: 4s; }

        @keyframes float {
            0%, 100% { transform: translateY(0px); }
            50% { transform: translateY(-20px); }
        }

        /* Game Section */
        .game-section {
            padding: 6rem 0;
            background: #f8fafc;
        }

        .section-title {
            font-size: 2.5rem;
            font-weight: 700;
            text-align: center;
            margin-bottom: 1rem;
            color: #1e293b;
        }

        .section-subtitle {
            text-align: center;
            font-size: 1.1rem;
            color: #64748b;
            margin-bottom: 3rem;
            max-width: 600px;
            margin-left: auto;
            margin-right: auto;
        }

        .game-container {
            max-width: 800px;
            margin: 0 auto;
        }

        .game-controls {
            display: flex;
            justify-content: center;
            gap: 1rem;
            margin-bottom: 2rem;
            flex-wrap: wrap;
        }

        .control-group {
            display: flex;
            gap: 0.5rem;
            flex-wrap: wrap;
        }

        .game-btn {
            padding: 0.75rem 1.5rem;
            border: 2px solid #e2e8f0;
            background: white;
            border-radius: 25px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .game-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        }

        .game-btn.primary {
            background: #6366f1;
            color: white;
            border-color: #6366f1;
        }

        .game-btn.danger {
            background: #ef4444;
            color: white;
            border-color: #ef4444;
        }

        .board-container {
            display: flex;
            justify-content: center;
            margin: 2rem 0;
        }

        .sudoku-board {
            border-collapse: collapse;
            border: 3px solid #1e293b;
            border-radius: 12px;
            overflow: hidden;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            background: white;
        }

        .sudoku-board td {
            border: 1px solid #cbd5e1;
            width: 50px;
            height: 50px;
            padding: 0;
            position: relative;
        }

        .sudoku-board tr:nth-child(3n) td { border-bottom: 3px solid #1e293b; }
        .sudoku-board td:nth-child(3n) { border-right: 3px solid #1e293b; }

        .cell {
            width: 100%;
            height: 100%;
            text-align: center;
            font-size: 1.5rem;
            font-weight: 600;
            border: none;
            outline: none;
            background: transparent;
            color: #1e293b;
            transition: all 0.2s ease;
        }

        .cell:focus {
            background: #ddd6fe;
            box-shadow: inset 0 0 0 2px #6366f1;
        }

        .cell.given {
            background: #f1f5f9;
            color: #0f172a;
            font-weight: 700;
            cursor: default;
        }

        .cell.conflict {
            background: #fee2e2;
            color: #dc2626;
        }

        .game-status {
            text-align: center;
            font-size: 1.1rem;
            font-weight: 600;
            min-height: 2rem;
            margin-top: 1rem;
            padding: 1rem;
            border-radius: 12px;
            background: white;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
        }

        /* Features Section */
        .features-section {
            padding: 6rem 0;
            background: white;
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 2rem;
            margin-top: 3rem;
        }

        .feature-card {
            text-align: center;
            padding: 2rem;
            border-radius: 16px;
            background: #f8fafc;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }

        .feature-icon {
            font-size: 3rem;
            margin-bottom: 1rem;
        }

        .feature-card h3 {
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 1rem;
            color: #1e293b;
        }

        /* About Section */
        .about-section {
            padding: 6rem 0;
            background: #f8fafc;
        }

        .about-content {
            display: grid;
            grid-template-columns: 1fr 1fr;
            align-items: center;
            gap: 4rem;
        }

        .about-text p {
            font-size: 1.1rem;
            color: #64748b;
            margin-bottom: 1.5rem;
        }

        .stats {
            display: flex;
            gap: 2rem;
            margin-top: 2rem;
        }

        .stat {
            text-align: center;
        }

        .stat-number {
            display: block;
            font-size: 2rem;
            font-weight: 700;
            color: #6366f1;
        }

        .stat-label {
            font-size: 0.9rem;
            color: #64748b;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .puzzle-preview {
            display: flex;
            justify-content: center;
        }

        .mini-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 8px;
            padding: 2rem;
            background: white;
            border-radius: 16px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }

        .mini-cell {
            width: 50px;
            height: 50px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: #f1f5f9;
            border-radius: 8px;
            font-weight: 600;
            font-size: 1.5rem;
            color: #1e293b;
        }

        .mini-cell.filled {
            background: #6366f1;
            color: white;
        }

        /* Footer */
        .footer {
            background: #1e293b;
            color: white;
            padding: 3rem 0 1rem;
        }

        .footer-content {
            display: grid;
            grid-template-columns: 1fr 2fr;
            gap: 3rem;
            margin-bottom: 2rem;
        }

        .footer-brand h3 {
            color: #6366f1;
            margin-bottom: 1rem;
        }

        .footer-links {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 2rem;
        }

        .footer-column h4 {
            color: #6366f1;
            margin-bottom: 1rem;
        }

        .footer-column ul {
            list-style: none;
        }

        .footer-column li {
            margin-bottom: 0.5rem;
        }

        .footer-column a {
            color: #cbd5e1;
            text-decoration: none;
            transition: color 0.3s ease;
        }

        .footer-column a:hover {
            color: #6366f1;
        }

        .footer-bottom {
            border-top: 1px solid #334155;
            padding-top: 2rem;
            text-align: center;
            color: #94a3b8;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .hero-content {
                grid-template-columns: 1fr;
                text-align: center;
            }

            .hero-title {
                font-size: 2.5rem;
            }

            .about-content {
                grid-template-columns: 1fr;
            }

            .footer-content {
                grid-template-columns: 1fr;
            }

            .nav-links {
                display: none;
            }

            .sudoku-board td {
                width: 35px;
                height: 35px;
            }

            .cell {
                font-size: 1.2rem;
            }

            .stats {
                justify-content: center;
            }
        }

        @media (max-width: 480px) {
            .hero-buttons {
                flex-direction: column;
                align-items: center;
            }

            .game-controls {
                flex-direction: column;
                align-items: center;
            }

            .control-group {
                justify-content: center;
            }
        }
.cell.wrong {
    background: #fee2e2 !important;
    color: #dc2626 !important;
    border: 2px solid #dc2626 !important;
}
/* Hero Section Mobile Responsiveness */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
        padding: 4rem 20px 2rem;
    }

    .hero-title {
        font-size: 2.5rem;
        line-height: 1.1;
    }

    .hero-subtitle {
        font-size: 1.1rem;
        margin-bottom: 1.5rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }

    .btn {
        width: 100%;
        max-width: 280px;
        padding: 1rem 1.5rem;
    }

    /* Hide floating numbers on mobile */
    .hero-visual {
        display: none;
    }
}

@media (max-width: 480px) {
    .hero {
        min-height: 90vh;
        padding-top: 80px;
    }

    .hero-title {
        font-size: 2rem;
        margin-bottom: 1rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .btn {
        font-size: 1rem;
        padding: 0.875rem 1.25rem;
    }
}}