:root {
            --primary: #4361ee;
            --secondary: #3a0ca3;
            --accent: #f72585;
            --light: #f8f9fa;
            --dark: #212529;
            --gray: #6c757d;
            --border: #dee2e6;
            --shadow: 0 5px 15px rgba(0,0,0,0.08);
            --transition: all 0.3s ease;
            --radius: 12px;
            --max-width: 1200px;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
            font-size: 16px;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
            line-height: 1.7;
            color: var(--dark);
            background-color: #fff;
            overflow-x: hidden;
        }
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 20px;
        }
        header {
            background: white;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
        }
        .my-logo {
            font-size: 2rem;
            font-weight: 800;
            color: var(--primary);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
            transition: var(--transition);
        }
        .my-logo:hover {
            color: var(--secondary);
            transform: translateY(-2px);
        }
        .my-logo i {
            color: var(--accent);
        }
        .desktop-nav ul {
            display: flex;
            list-style: none;
            gap: 30px;
        }
        .desktop-nav a {
            text-decoration: none;
            color: var(--dark);
            font-weight: 600;
            font-size: 1rem;
            padding: 8px 0;
            position: relative;
            transition: var(--transition);
        }
        .desktop-nav a:hover {
            color: var(--primary);
        }
        .desktop-nav a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 3px;
            background: var(--accent);
            transition: width 0.3s ease;
        }
        .desktop-nav a:hover::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            background: none;
            border: none;
            font-size: 1.8rem;
            color: var(--primary);
            cursor: pointer;
            padding: 5px;
        }
        .mobile-nav {
            display: none;
            position: absolute;
            top: 100%;
            left: 0;
            width: 100%;
            background: white;
            box-shadow: var(--shadow);
            flex-direction: column;
            padding: 20px;
            transform: translateY(-10px);
            opacity: 0;
            transition: var(--transition);
        }
        .mobile-nav.active {
            display: flex;
            transform: translateY(0);
            opacity: 1;
        }
        .mobile-nav ul {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        .mobile-nav a {
            text-decoration: none;
            color: var(--dark);
            font-weight: 600;
            padding: 10px;
            display: block;
            border-radius: var(--radius);
            transition: var(--transition);
        }
        .mobile-nav a:hover {
            background: var(--light);
            color: var(--primary);
            padding-left: 15px;
        }
        .breadcrumb {
            padding: 15px 0;
            background: var(--light);
            margin-bottom: 30px;
            font-size: 0.9rem;
        }
        .breadcrumb ul {
            display: flex;
            list-style: none;
            flex-wrap: wrap;
            gap: 10px;
        }
        .breadcrumb li:not(:last-child)::after {
            content: '›';
            margin-left: 10px;
            color: var(--gray);
        }
        .breadcrumb a {
            color: var(--gray);
            text-decoration: none;
            transition: var(--transition);
        }
        .breadcrumb a:hover {
            color: var(--primary);
        }
        .breadcrumb .current {
            color: var(--dark);
            font-weight: 600;
        }
        main {
            padding: 30px 0 60px;
        }
        .article-header {
            margin-bottom: 40px;
            text-align: center;
        }
        h1 {
            font-size: 2.8rem;
            color: var(--secondary);
            margin-bottom: 20px;
            line-height: 1.2;
        }
        @media (max-width: 768px) {
            h1 {
                font-size: 2.2rem;
            }
        }
        .article-meta {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 20px;
            color: var(--gray);
            font-size: 0.95rem;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }
        .article-meta i {
            color: var(--primary);
            margin-right: 5px;
        }
        .intro {
            font-size: 1.2rem;
            color: var(--dark);
            max-width: 800px;
            margin: 0 auto 40px;
            text-align: center;
            padding: 20px;
            background: linear-gradient(135deg, #f5f7ff 0%, #f0f2ff 100%);
            border-radius: var(--radius);
            border-left: 5px solid var(--primary);
        }
        .content-section {
            margin-bottom: 50px;
        }
        h2 {
            font-size: 2rem;
            color: var(--primary);
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 3px solid var(--accent);
            display: inline-block;
        }
        h3 {
            font-size: 1.6rem;
            color: var(--secondary);
            margin: 30px 0 15px;
        }
        h4 {
            font-size: 1.3rem;
            color: var(--dark);
            margin: 25px 0 12px;
        }
        p {
            margin-bottom: 20px;
            text-align: justify;
        }
        .highlight {
            background: linear-gradient(120deg, #e3f2fd 0%, #f3e5f5 100%);
            padding: 25px;
            border-radius: var(--radius);
            border-left: 5px solid var(--accent);
            margin: 30px 0;
        }
        .highlight p {
            margin-bottom: 0;
            font-size: 1.1rem;
        }
        .word-category {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
            margin: 30px 0;
        }
        .category-card {
            background: white;
            border-radius: var(--radius);
            padding: 25px;
            box-shadow: var(--shadow);
            transition: var(--transition);
            border-top: 5px solid var(--primary);
        }
        .category-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0,0,0,0.12);
        }
        .category-card h4 {
            color: var(--primary);
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .category-card ul {
            list-style: none;
            padding-left: 0;
        }
        .category-card li {
            padding: 8px 0;
            border-bottom: 1px dashed var(--border);
            display: flex;
            justify-content: space-between;
        }
        .category-card li:last-child {
            border-bottom: none;
        }
        .difficulty {
            font-size: 0.8rem;
            padding: 3px 10px;
            border-radius: 20px;
            background: var(--light);
            color: var(--gray);
        }
        .difficulty.hard {
            background: #ffeaea;
            color: #dc3545;
        }
        .difficulty.medium {
            background: #fff3cd;
            color: #856404;
        }
        .img-container {
            margin: 40px 0;
            text-align: center;
        }
        .featured-img {
            max-width: 100%;
            height: auto;
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            transition: var(--transition);
        }
        .featured-img:hover {
            transform: scale(1.02);
        }
        .img-caption {
            margin-top: 10px;
            font-style: italic;
            color: var(--gray);
            font-size: 0.9rem;
        }
        .interactive-section {
            background: var(--light);
            padding: 40px;
            border-radius: var(--radius);
            margin: 50px 0;
        }
        .search-box {
            display: flex;
            max-width: 600px;
            margin: 0 auto 30px;
        }
        .search-box input {
            flex: 1;
            padding: 15px 20px;
            border: 2px solid var(--border);
            border-right: none;
            border-radius: var(--radius) 0 0 var(--radius);
            font-size: 1rem;
            transition: var(--transition);
        }
        .search-box input:focus {
            outline: none;
            border-color: var(--primary);
        }
        .search-box button {
            background: var(--primary);
            color: white;
            border: none;
            padding: 0 30px;
            border-radius: 0 var(--radius) var(--radius) 0;
            cursor: pointer;
            font-weight: 600;
            transition: var(--transition);
        }
        .search-box button:hover {
            background: var(--secondary);
        }
        .rating-section, .comment-section {
            background: white;
            padding: 30px;
            border-radius: var(--radius);
            margin: 30px 0;
            box-shadow: var(--shadow);
        }
        .rating-stars {
            display: flex;
            gap: 10px;
            margin: 20px 0;
            font-size: 1.8rem;
            color: #ffd700;
        }
        .star {
            cursor: pointer;
            transition: var(--transition);
        }
        .star:hover {
            transform: scale(1.2);
        }
        .rating-form, .comment-form {
            display: flex;
            flex-direction: column;
            gap: 20px;
            margin-top: 20px;
        }
        .form-group {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }
        .form-group label {
            font-weight: 600;
            color: var(--dark);
        }
        .form-group input,
        .form-group textarea,
        .form-group select {
            padding: 12px 15px;
            border: 2px solid var(--border);
            border-radius: var(--radius);
            font-size: 1rem;
            transition: var(--transition);
        }
        .form-group input:focus,
        .form-group textarea:focus,
        .form-group select:focus {
            outline: none;
            border-color: var(--primary);
        }
        .form-group textarea {
            min-height: 150px;
            resize: vertical;
        }
        .submit-btn {
            background: var(--primary);
            color: white;
            border: none;
            padding: 15px 30px;
            border-radius: var(--radius);
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            align-self: flex-start;
        }
        .submit-btn:hover {
            background: var(--secondary);
            transform: translateY(-3px);
        }
        .internal-links {
            background: linear-gradient(135deg, #4361ee15 0%, #3a0ca315 100%);
            padding: 25px;
            border-radius: var(--radius);
            margin: 40px 0;
        }
        .internal-links h3 {
            margin-top: 0;
        }
        .links-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 15px;
            margin-top: 20px;
        }
        .links-grid a {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 12px 15px;
            background: white;
            border-radius: var(--radius);
            text-decoration: none;
            color: var(--dark);
            transition: var(--transition);
            box-shadow: 0 3px 10px rgba(0,0,0,0.05);
        }
        .links-grid a:hover {
            background: var(--primary);
            color: white;
            transform: translateX(5px);
        }
        .links-grid i {
            color: var(--accent);
        }
        .links-grid a:hover i {
            color: white;
        }
        footer {
            background: var(--dark);
            color: white;
            padding: 60px 0 30px;
        }
        .footer-container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 40px;
        }
        .footer-section h3 {
            color: white;
            font-size: 1.3rem;
            margin-bottom: 20px;
            border-bottom: 2px solid var(--primary);
            padding-bottom: 10px;
        }
        .footer-links {
            list-style: none;
        }
        .footer-links li {
            margin-bottom: 12px;
        }
        .footer-links a {
            color: #b0b7c3;
            text-decoration: none;
            transition: var(--transition);
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .footer-links a:hover {
            color: white;
            padding-left: 5px;
        }
        friend-link {
            display: block;
            background: rgba(255,255,255,0.1);
            padding: 15px;
            border-radius: var(--radius);
            margin-bottom: 15px;
            transition: var(--transition);
        }
        friend-link:hover {
            background: rgba(255,255,255,0.2);
        }
        friend-link a {
            color: white;
            text-decoration: none;
            font-weight: 600;
        }
        friend-link a:hover {
            text-decoration: underline;
        }
        .copyright {
            text-align: center;
            padding-top: 30px;
            border-top: 1px solid rgba(255,255,255,0.1);
            color: #b0b7c3;
            font-size: 0.9rem;
        }
        .text-center { text-align: center; }
        .mb-20 { margin-bottom: 20px; }
        .mb-30 { margin-bottom: 30px; }
        .mt-40 { margin-top: 40px; }
        .bold { font-weight: 700; }
        .italic { font-style: italic; }
        .emoji { font-size: 1.2rem; }
        @media (max-width: 992px) {
            .word-category {
                grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            }
        }
        @media (max-width: 768px) {
            .desktop-nav {
                display: none;
            }
            .hamburger {
                display: block;
            }
            h2 {
                font-size: 1.8rem;
            }
            h3 {
                font-size: 1.4rem;
            }
            .interactive-section,
            .rating-section,
            .comment-section {
                padding: 25px;
            }
            .footer-container {
                grid-template-columns: 1fr;
            }
        }
        @media (max-width: 576px) {
            .search-box {
                flex-direction: column;
            }
            .search-box input {
                border-radius: var(--radius);
                border-right: 2px solid var(--border);
                margin-bottom: 10px;
            }
            .search-box button {
                border-radius: var(--radius);
                padding: 15px;
            }
            .word-category {
                grid-template-columns: 1fr;
            }
        }