:root {
            --primary-color: #2c3e50;
            --secondary-color: #3498db;
            --accent-color: #e74c3c;
            --light-color: #ecf0f1;
            --dark-color: #1a1a1a;
            --text-color: #333;
            --spacing-unit: 1rem;
            --max-width: 1200px;
            --border-radius: 8px;
            --transition: all 0.3s ease;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            font-size: 16px;
            scroll-behavior: smooth;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.8;
            color: var(--text-color);
            background-color: #f9f9f9;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }
        a {
            color: var(--secondary-color);
            text-decoration: none;
            transition: var(--transition);
        }
        a:hover {
            color: var(--accent-color);
            text-decoration: underline;
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
            border-radius: var(--border-radius);
        }
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 var(--spacing-unit);
        }
        .site-header {
            background-color: var(--primary-color);
            color: var(--light-color);
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .my-logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--light-color);
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .my-logo:hover {
            color: var(--secondary-color);
            text-decoration: none;
        }
        .my-logo i {
            color: var(--accent-color);
        }
        .main-nav ul {
            display: flex;
            list-style: none;
            gap: 2rem;
        }
        .main-nav a {
            color: var(--light-color);
            font-weight: 500;
            padding: 0.5rem 0;
            position: relative;
        }
        .main-nav a:hover {
            color: var(--secondary-color);
            text-decoration: none;
        }
        .main-nav a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--secondary-color);
            transition: var(--transition);
        }
        .main-nav a:hover::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            background: none;
            border: none;
            color: var(--light-color);
            font-size: 1.5rem;
            cursor: pointer;
        }
        .breadcrumb {
            background-color: var(--light-color);
            padding: 0.75rem 0;
            border-bottom: 1px solid #ddd;
            font-size: 0.9rem;
        }
        .breadcrumb ol {
            display: flex;
            list-style: none;
            flex-wrap: wrap;
        }
        .breadcrumb li:not(:last-child)::after {
            content: '/';
            margin: 0 0.5rem;
            color: #777;
        }
        .main-content {
            flex: 1;
            padding: 2rem 0;
        }
        .article-header {
            text-align: center;
            margin-bottom: 3rem;
            padding-bottom: 2rem;
            border-bottom: 2px solid var(--secondary-color);
        }
        .article-header h1 {
            font-size: 2.8rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
            line-height: 1.2;
        }
        .article-meta {
            color: #666;
            font-style: italic;
            margin-top: 1rem;
        }
        .content-section {
            margin-bottom: 3rem;
            background-color: white;
            padding: 2rem;
            border-radius: var(--border-radius);
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            transition: var(--transition);
        }
        .content-section:hover {
            box-shadow: 0 8px 25px rgba(0,0,0,0.1);
        }
        h2 {
            color: var(--primary-color);
            font-size: 2.2rem;
            margin-bottom: 1.5rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--light-color);
        }
        h3 {
            color: var(--secondary-color);
            font-size: 1.8rem;
            margin: 1.8rem 0 1rem;
        }
        h4 {
            color: var(--accent-color);
            font-size: 1.4rem;
            margin: 1.5rem 0 0.8rem;
        }
        p {
            margin-bottom: 1.5rem;
            text-align: justify;
        }
        .highlight {
            background-color: #fffacd;
            padding: 1.5rem;
            border-left: 4px solid var(--secondary-color);
            margin: 1.5rem 0;
            border-radius: 0 var(--border-radius) var(--border-radius) 0;
        }
        .image-container {
            margin: 2rem auto;
            text-align: center;
        }
        .image-container figcaption {
            font-style: italic;
            color: #666;
            margin-top: 0.5rem;
        }
        .quote {
            font-style: italic;
            color: #555;
            border-left: 3px solid var(--accent-color);
            padding-left: 1.5rem;
            margin: 2rem 0;
        }
        .feature-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }
        .feature-card {
            background: var(--light-color);
            padding: 1.5rem;
            border-radius: var(--border-radius);
            border-top: 4px solid var(--secondary-color);
        }
        .interactive-module {
            background-color: #f0f8ff;
            padding: 2rem;
            border-radius: var(--border-radius);
            margin: 3rem 0;
        }
        .module-title {
            color: var(--primary-color);
            margin-bottom: 1.5rem;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        form {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        .form-group {
            display: flex;
            flex-direction: column;
        }
        label {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--primary-color);
        }
        input, textarea, select {
            padding: 0.8rem;
            border: 1px solid #ccc;
            border-radius: var(--border-radius);
            font-family: inherit;
            font-size: 1rem;
            transition: var(--transition);
        }
        input:focus, textarea:focus, select:focus {
            outline: none;
            border-color: var(--secondary-color);
            box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
        }
        button {
            background-color: var(--secondary-color);
            color: white;
            border: none;
            padding: 0.9rem 1.8rem;
            border-radius: var(--border-radius);
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            align-self: flex-start;
        }
        button:hover {
            background-color: var(--primary-color);
            transform: translateY(-2px);
        }
        .rating {
            display: flex;
            gap: 5px;
            margin: 0.5rem 0;
        }
        .rating input {
            display: none;
        }
        .rating label {
            font-size: 1.8rem;
            color: #ddd;
            cursor: pointer;
            transition: var(--transition);
        }
        .rating input:checked ~ label,
        .rating label:hover,
        .rating label:hover ~ label {
            color: #ffc107;
        }
        .site-footer {
            background-color: var(--dark-color);
            color: var(--light-color);
            padding: 3rem 0 1.5rem;
            margin-top: 3rem;
        }
        .footer-container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 2rem;
            margin-bottom: 2rem;
        }
        .footer-section h4 {
            color: var(--light-color);
            margin-bottom: 1.5rem;
            font-size: 1.3rem;
        }
        .footer-section ul {
            list-style: none;
        }
        .footer-section li {
            margin-bottom: 0.8rem;
        }
        .footer-section a {
            color: #bbb;
        }
        .footer-section a:hover {
            color: var(--secondary-color);
        }
        friend-link {
            display: block;
            background-color: #2a2a2a;
            padding: 1rem;
            border-radius: var(--border-radius);
            margin-bottom: 1rem;
            border-left: 4px solid var(--secondary-color);
        }
        .copyright {
            text-align: center;
            padding-top: 1.5rem;
            border-top: 1px solid #444;
            color: #aaa;
            font-size: 0.9rem;
        }
        @media (max-width: 768px) {
            html {
                font-size: 14px;
            }
            .header-container {
                flex-wrap: wrap;
            }
            .hamburger {
                display: block;
            }
            .main-nav {
                width: 100%;
                display: none;
                margin-top: 1rem;
            }
            .main-nav.active {
                display: block;
            }
            .main-nav ul {
                flex-direction: column;
                gap: 0;
            }
            .main-nav li {
                border-bottom: 1px solid #34495e;
            }
            .main-nav a {
                display: block;
                padding: 0.8rem 0;
            }
            .article-header h1 {
                font-size: 2.2rem;
            }
            h2 {
                font-size: 1.8rem;
            }
            h3 {
                font-size: 1.5rem;
            }
            .content-section {
                padding: 1.5rem;
            }
            .feature-list {
                grid-template-columns: 1fr;
            }
        }