* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        :root {
            --primary-color: #4a6fa5;
            --secondary-color: #ff6b6b;
            --accent-color: #51cf66;
            --dark-color: #2d3436;
            --light-color: #f8f9fa;
            --gray-color: #adb5bd;
            --text-color: #333;
            --text-light: #666;
            --border-color: #dee2e6;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s ease;
            --max-width: 1200px;
            --header-height: 80px;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background-color: #fff;
            overflow-x: hidden;
        }
        a {
            text-decoration: none;
            color: var(--primary-color);
            transition: var(--transition);
        }
        a:hover {
            color: var(--secondary-color);
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        ul, ol {
            margin-left: 1.5rem;
            margin-bottom: 1.5rem;
        }
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 1.5rem;
        }
        header {
            background-color: white;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
            height: var(--header-height);
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 100%;
        }
        .logo a {
            font-size: 1.8rem;
            font-weight: 800;
            color: var(--primary-color);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .logo i {
            color: var(--secondary-color);
        }
        .nav-desktop {
            display: flex;
            gap: 2rem;
        }
        .nav-desktop a {
            font-weight: 600;
            color: var(--dark-color);
            position: relative;
            padding: 0.5rem 0;
        }
        .nav-desktop a:hover {
            color: var(--primary-color);
        }
        .nav-desktop a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 3px;
            background-color: var(--primary-color);
            transition: var(--transition);
        }
        .nav-desktop a:hover::after {
            width: 100%;
        }
        .search-box {
            display: flex;
            align-items: center;
            background-color: var(--light-color);
            border-radius: 50px;
            padding: 0.5rem 1rem;
            width: 250px;
        }
        .search-box input {
            border: none;
            background: transparent;
            padding: 0.5rem;
            width: 100%;
            outline: none;
            font-size: 0.95rem;
        }
        .search-box button {
            background: none;
            border: none;
            color: var(--gray-color);
            cursor: pointer;
            font-size: 1rem;
        }
        .hamburger {
            display: none;
            flex-direction: column;
            cursor: pointer;
            gap: 4px;
        }
        .hamburger span {
            width: 25px;
            height: 3px;
            background-color: var(--dark-color);
            transition: var(--transition);
        }
        .nav-mobile {
            position: fixed;
            top: var(--header-height);
            left: 0;
            width: 100%;
            background-color: white;
            box-shadow: var(--shadow);
            padding: 1.5rem;
            transform: translateY(-100%);
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
            z-index: 999;
        }
        .nav-mobile.active {
            transform: translateY(0);
            opacity: 1;
            visibility: visible;
        }
        .nav-mobile ul {
            list-style: none;
            margin: 0;
        }
        .nav-mobile li {
            margin-bottom: 1rem;
        }
        .nav-mobile a {
            display: block;
            padding: 0.75rem;
            font-weight: 600;
            color: var(--dark-color);
            border-radius: 5px;
            transition: var(--transition);
        }
        .nav-mobile a:hover {
            background-color: var(--light-color);
            color: var(--primary-color);
        }
        .breadcrumb {
            background-color: var(--light-color);
            padding: 1rem 0;
            margin-bottom: 2rem;
            font-size: 0.9rem;
        }
        .breadcrumb a {
            color: var(--text-light);
        }
        .breadcrumb a:hover {
            color: var(--primary-color);
        }
        .breadcrumb span {
            color: var(--gray-color);
            margin: 0 0.5rem;
        }
        main {
            padding: 2rem 0;
            min-height: calc(100vh - 400px);
        }
        .article-header {
            margin-bottom: 3rem;
            text-align: center;
            padding-bottom: 2rem;
            border-bottom: 1px solid var(--border-color);
        }
        .article-header h1 {
            font-size: 2.8rem;
            line-height: 1.2;
            margin-bottom: 1rem;
            color: var(--dark-color);
        }
        .article-meta {
            display: flex;
            justify-content: center;
            gap: 2rem;
            color: var(--text-light);
            font-size: 0.9rem;
            margin-top: 1.5rem;
        }
        .article-meta span {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .content-wrapper {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 3rem;
        }
        @media (max-width: 992px) {
            .content-wrapper {
                grid-template-columns: 1fr;
            }
        }
        h1, h2, h3, h4 {
            color: var(--dark-color);
            margin-top: 2.5rem;
            margin-bottom: 1rem;
            line-height: 1.3;
        }
        h1 { font-size: 2.8rem; }
        h2 { font-size: 2.2rem; border-bottom: 2px solid var(--primary-color); padding-bottom: 0.5rem; }
        h3 { font-size: 1.8rem; }
        h4 { font-size: 1.4rem; color: var(--primary-color); }
        p {
            margin-bottom: 1.5rem;
            font-size: 1.1rem;
        }
        .lead {
            font-size: 1.3rem;
            font-weight: 500;
            color: var(--text-color);
            margin-bottom: 2rem;
            padding: 1.5rem;
            background-color: #f8f9fa;
            border-left: 4px solid var(--primary-color);
            border-radius: 0 5px 5px 0;
        }
        .highlight {
            background-color: #fff9db;
            padding: 1.5rem;
            border-radius: 8px;
            margin: 2rem 0;
            border-left: 4px solid #ffd43b;
        }
        .highlight h3 {
            margin-top: 0;
            color: #e67700;
        }
        .key-term {
            font-weight: 700;
            color: var(--primary-color);
        }
        .bold {
            font-weight: 700;
        }
        .italic {
            font-style: italic;
        }
        .article-image {
            margin: 2rem auto;
            max-width: 800px;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: var(--shadow);
        }
        .article-image img {
            width: 100%;
            transition: var(--transition);
        }
        .article-image:hover img {
            transform: scale(1.02);
        }
        .image-caption {
            text-align: center;
            font-style: italic;
            color: var(--text-light);
            margin-top: 0.5rem;
            font-size: 0.95rem;
        }
        .sidebar {
            background-color: var(--light-color);
            padding: 2rem;
            border-radius: 10px;
            height: fit-content;
            position: sticky;
            top: calc(var(--header-height) + 2rem);
        }
        .sidebar h3 {
            margin-top: 0;
            color: var(--primary-color);
            font-size: 1.5rem;
            margin-bottom: 1.5rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--border-color);
        }
        .sidebar-nav ul {
            list-style: none;
            margin: 0;
        }
        .sidebar-nav li {
            margin-bottom: 0.75rem;
        }
        .sidebar-nav a {
            display: block;
            padding: 0.75rem 1rem;
            background-color: white;
            border-radius: 5px;
            transition: var(--transition);
            border-left: 3px solid transparent;
        }
        .sidebar-nav a:hover {
            background-color: #e7f5ff;
            border-left-color: var(--primary-color);
        }
        .popular-articles {
            margin-top: 2rem;
        }
        .popular-articles ul {
            list-style: none;
            margin: 0;
        }
        .popular-articles li {
            margin-bottom: 1rem;
            padding-bottom: 1rem;
            border-bottom: 1px solid var(--border-color);
        }
        .popular-articles a {
            font-weight: 600;
            color: var(--dark-color);
        }
        .popular-articles a:hover {
            color: var(--primary-color);
        }
        .interactive-section {
            background-color: white;
            border-radius: 10px;
            padding: 2rem;
            margin: 3rem 0;
            box-shadow: var(--shadow);
            border-top: 5px solid var(--accent-color);
        }
        .interactive-section h3 {
            margin-top: 0;
            display: flex;
            align-items: center;
            gap: 0.75rem;
        }
        .interactive-section h3 i {
            color: var(--accent-color);
        }
        .form-group {
            margin-bottom: 1.5rem;
        }
        .form-group label {
            display: block;
            margin-bottom: 0.5rem;
            font-weight: 600;
        }
        .form-control {
            width: 100%;
            padding: 0.75rem 1rem;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            font-size: 1rem;
            transition: var(--transition);
        }
        .form-control:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(74, 111, 165, 0.1);
        }
        .rating-stars {
            display: flex;
            gap: 0.5rem;
            margin: 1rem 0;
        }
        .star {
            font-size: 1.8rem;
            color: var(--gray-color);
            cursor: pointer;
            transition: var(--transition);
        }
        .star:hover,
        .star.active {
            color: #ffd43b;
        }
        .btn {
            display: inline-block;
            padding: 0.75rem 2rem;
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: 5px;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            font-size: 1rem;
        }
        .btn:hover {
            background-color: #3a5a8c;
            transform: translateY(-2px);
            box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
        }
        .btn-secondary {
            background-color: var(--secondary-color);
        }
        .btn-secondary:hover {
            background-color: #e05a5a;
        }
        .comments-section {
            margin-top: 3rem;
        }
        .comment {
            background-color: var(--light-color);
            padding: 1.5rem;
            border-radius: 8px;
            margin-bottom: 1.5rem;
        }
        .comment-header {
            display: flex;
            justify-content: space-between;
            margin-bottom: 1rem;
            font-size: 0.9rem;
            color: var(--text-light);
        }
        .comment-author {
            font-weight: 700;
            color: var(--dark-color);
        }
        footer {
            background-color: var(--dark-color);
            color: white;
            padding: 4rem 0 2rem;
            margin-top: 4rem;
        }
        .footer-content {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 3rem;
            margin-bottom: 3rem;
        }
        @media (max-width: 768px) {
            .footer-content {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        @media (max-width: 576px) {
            .footer-content {
                grid-template-columns: 1fr;
            }
        }
        .footer-section h3 {
            color: white;
            font-size: 1.3rem;
            margin-bottom: 1.5rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--primary-color);
        }
        .footer-section ul {
            list-style: none;
            margin: 0;
        }
        .footer-section li {
            margin-bottom: 0.75rem;
        }
        .footer-section a {
            color: #ccc;
        }
        .footer-section a:hover {
            color: white;
            padding-left: 5px;
        }
        .friend-links {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            margin-top: 1rem;
        }
        .friend-link {
            background-color: rgba(255, 255, 255, 0.1);
            padding: 0.5rem 1rem;
            border-radius: 5px;
            transition: var(--transition);
        }
        .friend-link:hover {
            background-color: rgba(255, 255, 255, 0.2);
        }
        .copyright {
            text-align: center;
            padding-top: 2rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            color: #aaa;
            font-size: 0.9rem;
        }
        @media (max-width: 992px) {
            h1 { font-size: 2.4rem; }
            h2 { font-size: 1.9rem; }
            h3 { font-size: 1.6rem; }
            .nav-desktop, .search-box {
                display: none;
            }
            .hamburger {
                display: flex;
            }
            .article-header h1 {
                font-size: 2.2rem;
            }
        }
        @media (max-width: 768px) {
            .container {
                padding: 0 1rem;
            }
            h1 { font-size: 2rem; }
            h2 { font-size: 1.7rem; }
            h3 { font-size: 1.4rem; }
            .article-meta {
                flex-direction: column;
                align-items: center;
                gap: 0.5rem;
            }
            .sidebar {
                position: static;
            }
        }
        @media (max-width: 576px) {
            .header-container {
                padding: 0 1rem;
            }
            .article-header h1 {
                font-size: 1.8rem;
            }
            .interactive-section {
                padding: 1.5rem;
            }
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .fade-in {
            animation: fadeIn 0.8s ease forwards;
        }
        .text-center { text-align: center; }
        .mt-1 { margin-top: 1rem; }
        .mt-2 { margin-top: 2rem; }
        .mt-3 { margin-top: 3rem; }
        .mb-1 { margin-bottom: 1rem; }
        .mb-2 { margin-bottom: 2rem; }
        .mb-3 { margin-bottom: 3rem; }