:root {
            --primary-color: #4285f4;
            --secondary-color: #34a853;
            --accent-color: #ea4335;
            --dark-color: #202124;
            --light-color: #f8f9fa;
            --gray-color: #dadce0;
            --text-dark: #3c4043;
            --text-light: #ffffff;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --border-radius: 8px;
            --transition: all 0.3s ease;
            --max-width: 1200px;
            --font-heading: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            --font-body: 'Roboto', 'Open Sans', Arial, sans-serif;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: var(--font-body);
            line-height: 1.7;
            color: var(--text-dark);
            background-color: #fff;
            overflow-x: hidden;
        }
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 20px;
        }
        .site-header {
            background-color: var(--dark-color);
            color: var(--text-light);
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: var(--shadow);
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .my-logo {
            font-family: var(--font-heading);
            font-size: 2.2rem;
            font-weight: 800;
            color: var(--primary-color);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
            transition: var(--transition);
        }
        .my-logo:hover {
            color: var(--accent-color);
            transform: scale(1.03);
        }
        .my-logo i {
            font-size: 2rem;
        }
        .main-nav ul {
            display: flex;
            list-style: none;
            gap: 2rem;
        }
        .main-nav a {
            color: var(--text-light);
            text-decoration: none;
            font-weight: 500;
            font-size: 1.05rem;
            padding: 0.5rem 0;
            position: relative;
            transition: var(--transition);
        }
        .main-nav a:hover,
        .main-nav a.active {
            color: var(--secondary-color);
        }
        .main-nav a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 3px;
            background-color: var(--secondary-color);
            transition: width 0.3s ease;
        }
        .main-nav a:hover::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            flex-direction: column;
            cursor: pointer;
            background: transparent;
            border: none;
            gap: 5px;
        }
        .hamburger span {
            display: block;
            width: 25px;
            height: 3px;
            background-color: var(--text-light);
            border-radius: 2px;
            transition: var(--transition);
        }
        .hamburger.active span:nth-child(1) {
            transform: rotate(45deg) translate(6px, 6px);
        }
        .hamburger.active span:nth-child(2) {
            opacity: 0;
        }
        .hamburger.active span:nth-child(3) {
            transform: rotate(-45deg) translate(6px, -6px);
        }
        .breadcrumb {
            padding: 1rem 0;
            background-color: #f1f3f4;
            font-size: 0.9rem;
        }
        .breadcrumb ol {
            display: flex;
            list-style: none;
            flex-wrap: wrap;
            gap: 0.5rem;
        }
        .breadcrumb li:not(:last-child)::after {
            content: '›';
            margin-left: 0.5rem;
            color: #5f6368;
        }
        .breadcrumb a {
            color: var(--primary-color);
            text-decoration: none;
        }
        .breadcrumb a:hover {
            text-decoration: underline;
        }
        .hero {
            background: linear-gradient(135deg, #1a237e 0%, #283593 100%);
            color: white;
            padding: 4rem 2rem;
            text-align: center;
            border-radius: 0 0 var(--border-radius) var(--border-radius);
            margin-bottom: 3rem;
        }
        .hero h1 {
            font-size: 3rem;
            margin-bottom: 1rem;
            font-family: var(--font-heading);
            text-shadow: 0 2px 4px rgba(0,0,0,0.3);
        }
        .hero p {
            font-size: 1.3rem;
            max-width: 800px;
            margin: 0 auto 2rem;
            opacity: 0.9;
        }
        .main-content {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 3rem;
            padding: 2rem 0;
        }
        @media (max-width: 992px) {
            .main-content {
                grid-template-columns: 1fr;
            }
        }
        article {
            background: #fff;
            border-radius: var(--border-radius);
            padding: 2.5rem;
            box-shadow: var(--shadow);
        }
        article h1,
        article h2,
        article h3,
        article h4 {
            font-family: var(--font-heading);
            color: var(--dark-color);
            margin-top: 2.5rem;
            margin-bottom: 1rem;
            line-height: 1.3;
        }
        article h1 {
            font-size: 2.8rem;
            color: #1a237e;
            border-bottom: 3px solid var(--primary-color);
            padding-bottom: 0.5rem;
        }
        article h2 {
            font-size: 2.2rem;
            color: #283593;
            padding-left: 1rem;
            border-left: 5px solid var(--secondary-color);
        }
        article h3 {
            font-size: 1.8rem;
            color: #3949ab;
        }
        article h4 {
            font-size: 1.5rem;
            color: #5c6bc0;
        }
        article p {
            margin-bottom: 1.5rem;
            font-size: 1.1rem;
            text-align: justify;
        }
        article strong {
            color: var(--primary-color);
            font-weight: 700;
        }
        article em {
            color: #d81b60;
            font-style: italic;
        }
        article blockquote {
            border-left: 4px solid var(--accent-color);
            padding-left: 1.5rem;
            margin: 2rem 0;
            font-style: italic;
            color: #5f6368;
            background-color: #f8f9fa;
            padding: 1.5rem;
            border-radius: 0 var(--border-radius) var(--border-radius) 0;
        }
        article img {
            max-width: 100%;
            height: auto;
            display: block;
            margin: 2rem auto;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            transition: var(--transition);
        }
        article img:hover {
            transform: scale(1.02);
        }
        .figure-caption {
            text-align: center;
            font-style: italic;
            color: #666;
            margin-top: -1.5rem;
            margin-bottom: 2rem;
            font-size: 0.95rem;
        }
        article ul, article ol {
            margin-left: 2rem;
            margin-bottom: 1.5rem;
        }
        article li {
            margin-bottom: 0.5rem;
        }
        article a {
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 500;
            border-bottom: 1px dashed transparent;
            transition: var(--transition);
        }
        article a:hover {
            color: var(--accent-color);
            border-bottom-color: var(--accent-color);
        }
        .highlight-box {
            background: linear-gradient(145deg, #e3f2fd, #f3e5f5);
            border-radius: var(--border-radius);
            padding: 2rem;
            margin: 2.5rem 0;
            border-left: 6px solid var(--primary-color);
        }
        .sidebar {
            position: sticky;
            top: 120px;
            align-self: start;
        }
        .sidebar-widget {
            background: #fff;
            border-radius: var(--border-radius);
            padding: 1.8rem;
            margin-bottom: 2rem;
            box-shadow: var(--shadow);
        }
        .sidebar-widget h3 {
            font-size: 1.5rem;
            color: var(--dark-color);
            margin-bottom: 1.2rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--gray-color);
        }
        .search-form {
            display: flex;
        }
        .search-form input {
            flex-grow: 1;
            padding: 0.9rem 1rem;
            border: 2px solid var(--gray-color);
            border-right: none;
            border-radius: var(--border-radius) 0 0 var(--border-radius);
            font-size: 1rem;
            outline: none;
            transition: var(--transition);
        }
        .search-form input:focus {
            border-color: var(--primary-color);
        }
        .search-form button {
            background-color: var(--primary-color);
            color: white;
            border: none;
            padding: 0 1.5rem;
            border-radius: 0 var(--border-radius) var(--border-radius) 0;
            cursor: pointer;
            transition: var(--transition);
        }
        .search-form button:hover {
            background-color: #3367d6;
        }
        .rating-widget form {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        .rating-widget label {
            font-weight: 600;
        }
        .stars {
            display: flex;
            gap: 5px;
            font-size: 1.8rem;
            color: #ffc107;
            margin-bottom: 0.5rem;
        }
        .stars i {
            cursor: pointer;
            transition: var(--transition);
        }
        .stars i:hover {
            transform: scale(1.2);
        }
        .rating-widget textarea,
        .rating-widget input {
            padding: 0.9rem;
            border: 2px solid var(--gray-color);
            border-radius: var(--border-radius);
            font-family: inherit;
            font-size: 1rem;
            transition: var(--transition);
        }
        .rating-widget textarea:focus,
        .rating-widget input:focus {
            border-color: var(--primary-color);
            outline: none;
        }
        .rating-widget button {
            background-color: var(--secondary-color);
            color: white;
            border: none;
            padding: 1rem;
            border-radius: var(--border-radius);
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
        }
        .rating-widget button:hover {
            background-color: #2d8c47;
        }
        .toc {
            line-height: 1.6;
        }
        .toc ul {
            list-style: none;
            margin-left: 0;
        }
        .toc li {
            margin-bottom: 0.7rem;
        }
        .toc a {
            color: var(--text-dark);
            text-decoration: none;
            display: block;
            padding: 0.5rem 0.8rem;
            border-radius: 4px;
            transition: var(--transition);
        }
        .toc a:hover {
            background-color: #f1f3f4;
            color: var(--primary-color);
            padding-left: 1.2rem;
        }
        .toc .h3 {
            padding-left: 1.5rem;
            font-size: 0.95rem;
        }
        .site-footer {
            background-color: var(--dark-color);
            color: var(--text-light);
            padding: 3rem 0 1.5rem;
            margin-top: 4rem;
        }
        .footer-container {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 3rem;
        }
        .footer-section {
            flex: 1;
            min-width: 250px;
        }
        .footer-section h4 {
            font-size: 1.3rem;
            margin-bottom: 1.5rem;
            color: var(--secondary-color);
            position: relative;
            padding-bottom: 0.5rem;
        }
        .footer-section h4::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 50px;
            height: 3px;
            background-color: var(--primary-color);
        }
        .footer-links {
            list-style: none;
        }
        .footer-links li {
            margin-bottom: 0.8rem;
        }
        .footer-links a {
            color: #bdc1c6;
            text-decoration: none;
            transition: var(--transition);
        }
        .footer-links a:hover {
            color: var(--primary-color);
            padding-left: 5px;
        }
        friend-link {
            display: block;
            background-color: #2d2d2d;
            border: 1px solid #444;
            border-radius: var(--border-radius);
            padding: 1.5rem;
            margin-top: 2rem;
        }
        friend-link h4 {
            color: var(--accent-color);
            margin-bottom: 1rem;
        }
        friend-link ul {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 0.8rem;
            list-style: none;
        }
        friend-link a {
            color: #8ab4f8;
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: var(--transition);
        }
        friend-link a:hover {
            color: var(--secondary-color);
            transform: translateX(5px);
        }
        .copyright {
            text-align: center;
            margin-top: 3rem;
            padding-top: 1.5rem;
            border-top: 1px solid #444;
            color: #9aa0a6;
            font-size: 0.9rem;
        }
        .last-updated {
            background-color: #e8f0fe;
            color: #1a73e8;
            padding: 1rem;
            border-radius: var(--border-radius);
            margin: 2rem 0;
            font-weight: 600;
            display: inline-flex;
            align-items: center;
            gap: 10px;
        }
        @media (max-width: 768px) {
            .hamburger {
                display: flex;
            }
            .main-nav ul {
                position: fixed;
                top: 80px;
                right: -100%;
                flex-direction: column;
                background-color: var(--dark-color);
                width: 80%;
                max-width: 300px;
                height: calc(100vh - 80px);
                padding: 2rem;
                transition: right 0.4s ease;
                box-shadow: -5px 0 15px rgba(0,0,0,0.1);
                z-index: 999;
            }
            .main-nav.active ul {
                right: 0;
            }
            .hero h1 {
                font-size: 2.2rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            article {
                padding: 1.8rem;
            }
            article h1 {
                font-size: 2.2rem;
            }
            article h2 {
                font-size: 1.8rem;
            }
            article h3 {
                font-size: 1.5rem;
            }
        }