* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        :root {
            --primary-color: #2563eb;
            --secondary-color: #7c3aed;
            --accent-color: #f59e0b;
            --text-color: #1f2937;
            --light-bg: #f8fafc;
            --border-color: #e2e8f0;
            --success-color: #10b981;
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.8;
            color: var(--text-color);
            background-color: var(--light-bg);
            direction: ltr;
        }
        .header {
            background: white;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        .header-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 80px;
        }
        .logo {
            font-size: 2rem;
            font-weight: 800;
            color: var(--primary-color);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .logo i {
            color: var(--accent-color);
        }
        .nav-desktop {
            display: flex;
            gap: 30px;
        }
        .nav-link {
            text-decoration: none;
            color: var(--text-color);
            font-weight: 600;
            padding: 10px 0;
            position: relative;
            transition: var(--transition);
        }
        .nav-link:hover {
            color: var(--primary-color);
        }
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 3px;
            background: var(--primary-color);
            transition: var(--transition);
        }
        .nav-link:hover::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            font-size: 1.5rem;
            background: none;
            border: none;
            color: var(--text-color);
            cursor: pointer;
        }
        .nav-mobile {
            display: none;
            flex-direction: column;
            background: white;
            padding: 20px;
            box-shadow: var(--shadow);
        }
        .nav-mobile.active {
            display: flex;
        }
        .breadcrumb {
            background: #f1f5f9;
            padding: 15px 0;
            border-bottom: 1px solid var(--border-color);
        }
        .breadcrumb-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        .breadcrumb-item {
            color: #64748b;
            font-size: 0.9rem;
        }
        .breadcrumb-item a {
            color: var(--primary-color);
            text-decoration: none;
        }
        .breadcrumb-item:not(:last-child)::after {
            content: '›';
            margin-left: 10px;
        }
        .main-container {
            max-width: 1200px;
            margin: 30px auto;
            padding: 0 20px;
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 40px;
        }
        .article-content {
            background: white;
            padding: 40px;
            border-radius: 12px;
            box-shadow: var(--shadow);
        }
        .article-title {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 20px;
            line-height: 1.3;
        }
        .article-meta {
            display: flex;
            gap: 20px;
            margin-bottom: 30px;
            color: #64748b;
            font-size: 0.9rem;
        }
        .meta-item {
            display: flex;
            align-items: center;
            gap: 5px;
        }
        h1, h2, h3 {
            margin: 30px 0 15px;
            color: var(--primary-color);
        }
        h2 {
            font-size: 1.8rem;
            border-left: 5px solid var(--accent-color);
            padding-left: 15px;
        }
        h3 {
            font-size: 1.4rem;
            color: var(--secondary-color);
        }
        p {
            margin-bottom: 20px;
            font-size: 1.1rem;
            text-align: justify;
        }
        .highlight {
            background-color: #fef3c7;
            padding: 20px;
            border-radius: 8px;
            margin: 25px 0;
            border-left: 4px solid var(--accent-color);
        }
        .technique-box {
            background: #f8fafc;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 25px;
            margin: 25px 0;
            transition: var(--transition);
        }
        .technique-box:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow);
        }
        .technique-title {
            color: var(--secondary-color);
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 15px;
        }
        .sudoku-grid {
            display: grid;
            grid-template-columns: repeat(9, 1fr);
            gap: 2px;
            margin: 25px auto;
            max-width: 500px;
            border: 3px solid var(--text-color);
        }
        .sudoku-cell {
            aspect-ratio: 1;
            display: flex;
            align-items: center;
            justify-content: center;
            background: white;
            font-weight: bold;
            font-size: 1.2rem;
            border: 1px solid #94a3b8;
        }
        .sudoku-cell:nth-child(3n) {
            border-right: 2px solid var(--text-color);
        }
        .sudoku-cell:nth-child(n+19):nth-child(-n+27),
        .sudoku-cell:nth-child(n+46):nth-child(-n+54) {
            border-bottom: 2px solid var(--text-color);
        }
        .article-image {
            width: 100%;
            max-width: 800px;
            height: auto;
            border-radius: 10px;
            margin: 30px auto;
            display: block;
            box-shadow: var(--shadow);
        }
        .interactive-section {
            margin: 40px 0;
            padding: 30px;
            background: #f0f9ff;
            border-radius: 10px;
            border: 1px solid var(--border-color);
        }
        .search-form, .comment-form, .rating-form {
            margin-top: 20px;
        }
        .form-group {
            margin-bottom: 20px;
        }
        .form-label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
        }
        .form-input, .form-textarea {
            width: 100%;
            padding: 12px;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            font-size: 1rem;
            transition: var(--transition);
        }
        .form-input:focus, .form-textarea:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        }
        .form-textarea {
            min-height: 150px;
            resize: vertical;
        }
        .btn {
            background: var(--primary-color);
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 6px;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }
        .btn:hover {
            background: #1d4ed8;
            transform: translateY(-2px);
        }
        .btn-secondary {
            background: var(--secondary-color);
        }
        .btn-secondary:hover {
            background: #6d28d9;
        }
        .rating-stars {
            display: flex;
            gap: 5px;
            margin: 15px 0;
        }
        .star {
            font-size: 1.5rem;
            color: #e2e8f0;
            cursor: pointer;
            transition: var(--transition);
        }
        .star:hover,
        .star.active {
            color: var(--accent-color);
        }
        .sidebar {
            background: white;
            padding: 25px;
            border-radius: 12px;
            box-shadow: var(--shadow);
            height: fit-content;
            position: sticky;
            top: 100px;
        }
        .sidebar-title {
            color: var(--primary-color);
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--border-color);
        }
        .sidebar-list {
            list-style: none;
        }
        .sidebar-item {
            margin-bottom: 15px;
        }
        .sidebar-link {
            color: var(--text-color);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 10px;
            border-radius: 6px;
            transition: var(--transition);
        }
        .sidebar-link:hover {
            background: #f1f5f9;
            color: var(--primary-color);
        }
        .longtail-links {
            max-width: 1200px;
            margin: 40px auto;
            padding: 0 20px;
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 20px;
        }
        .web-link {
            background: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: var(--shadow);
            transition: var(--transition);
        }
        .web-link:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        }
        .web-link a {
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 600;
            display: block;
            line-height: 1.6;
        }
        .web-link a:hover {
            text-decoration: underline;
        }
        .footer {
            background: #1e293b;
            color: white;
            padding: 50px 0 20px;
            margin-top: 50px;
        }
        .footer-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        .footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 40px;
        }
        .footer-logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: white;
            margin-bottom: 15px;
            display: block;
        }
        .footer-description {
            color: #cbd5e1;
            line-height: 1.7;
        }
        .footer-title {
            color: white;
            margin-bottom: 20px;
            font-size: 1.2rem;
        }
        .footer-links {
            list-style: none;
        }
        .footer-links li {
            margin-bottom: 10px;
        }
        .footer-links a {
            color: #cbd5e1;
            text-decoration: none;
            transition: var(--transition);
        }
        .footer-links a:hover {
            color: white;
            padding-left: 5px;
        }
        .copyright {
            text-align: center;
            padding-top: 20px;
            border-top: 1px solid #334155;
            color: #94a3b8;
            font-size: 0.9rem;
        }
        @media (max-width: 992px) {
            .main-container {
                grid-template-columns: 1fr;
            }
            .sidebar {
                position: static;
            }
        }
        @media (max-width: 768px) {
            .header-container {
                height: 70px;
            }
            .nav-desktop {
                display: none;
            }
            .hamburger {
                display: block;
            }
            .article-title {
                font-size: 2rem;
            }
            .article-content {
                padding: 25px;
            }
            .sudoku-grid {
                max-width: 100%;
                font-size: 0.9rem;
            }
            .longtail-links {
                grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            }
        }
        @media (max-width: 480px) {
            .article-title {
                font-size: 1.6rem;
            }
            h2 {
                font-size: 1.4rem;
            }
            .interactive-section {
                padding: 20px;
            }
            .footer-content {
                grid-template-columns: 1fr;
            }
        }
        @media print {
            .header, .sidebar, .interactive-section, .longtail-links, .footer {
                display: none;
            }
            .article-content {
                box-shadow: none;
                padding: 0;
            }
            body {
                background: white;
                font-size: 12pt;
            }
        }
        .sr-only {
            position: absolute;
            width: 1px;
            height: 1px;
            padding: 0;
            margin: -1px;
            overflow: hidden;
            clip: rect(0, 0, 0, 0);
            white-space: nowrap;
            border: 0;
        }
        :focus-visible {
            outline: 2px solid var(--primary-color);
            outline-offset: 2px;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .article-content, .sidebar, .web-link {
            animation: fadeIn 0.5s ease-out;
        }