:root {
            --primary: #4CAF50;
            --secondary: #FF9800;
            --dark: #2E7D32;
            --light: #E8F5E9;
            --text: #333;
            --shadow: 0 4px 12px rgba(0,0,0,0.1);
            --radius: 8px;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        body {
            background-color: #f9f9f9;
            color: var(--text);
            line-height: 1.7;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 15px;
        }
        a {
            color: var(--dark);
            text-decoration: none;
            transition: color 0.3s;
        }
        a:hover {
            color: var(--secondary);
        }
        header {
            background: linear-gradient(135deg, var(--primary), var(--dark));
            color: white;
            padding: 1.5rem;
            border-radius: 0 0 var(--radius) var(--radius);
            box-shadow: var(--shadow);
            margin-bottom: 2rem;
        }
        .header-top {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
        }
        .my-logo {
            font-size: 2.2rem;
            font-weight: 800;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
        }
        .my-logo a {
            color: white;
        }
        .hamburger {
            display: none;
            font-size: 1.8rem;
            background: none;
            border: none;
            color: white;
            cursor: pointer;
        }
        nav ul {
            display: flex;
            list-style: none;
            gap: 1.8rem;
        }
        nav a {
            color: white;
            font-weight: 600;
            padding: 0.5rem 1rem;
            border-radius: var(--radius);
        }
        nav a:hover {
            background-color: rgba(255,255,255,0.2);
        }
        .breadcrumb {
            margin-top: 1rem;
            font-size: 0.9rem;
            color: var(--light);
        }
        .breadcrumb a {
            color: var(--light);
        }
        .content-wrapper {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 2.5rem;
        }
        main {
            background: white;
            padding: 2.5rem;
            border-radius: var(--radius);
            box-shadow: var(--shadow);
        }
        aside {
            background: white;
            padding: 1.8rem;
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            align-self: start;
        }
        h1 {
            color: var(--dark);
            font-size: 2.8rem;
            margin-bottom: 1.5rem;
            border-bottom: 3px solid var(--secondary);
            padding-bottom: 0.7rem;
        }
        h2 {
            color: var(--primary);
            font-size: 2rem;
            margin: 2.5rem 0 1.2rem;
            padding-left: 0.5rem;
            border-left: 5px solid var(--secondary);
        }
        h3 {
            color: var(--dark);
            font-size: 1.6rem;
            margin: 2rem 0 1rem;
        }
        h4 {
            color: #555;
            font-size: 1.3rem;
            margin: 1.5rem 0 0.8rem;
        }
        p {
            margin-bottom: 1.5rem;
            text-align: justify;
        }
        .lead {
            font-size: 1.3rem;
            font-weight: 500;
            color: var(--dark);
            background-color: var(--light);
            padding: 1.2rem;
            border-radius: var(--radius);
            margin-bottom: 2rem;
        }
        .highlight {
            background-color: #fffde7;
            border-left: 4px solid #FFC107;
            padding: 1.2rem;
            margin: 1.8rem 0;
            font-style: italic;
        }
        .featured-img {
            width: 100%;
            max-height: 500px;
            object-fit: cover;
            border-radius: var(--radius);
            margin: 2rem 0;
            box-shadow: var(--shadow);
        }
        .interactive-module {
            background: #f1f8e9;
            padding: 1.8rem;
            border-radius: var(--radius);
            margin: 2.5rem 0;
            border: 1px solid #c5e1a5;
        }
        .module-title {
            display: flex;
            align-items: center;
            gap: 10px;
            color: var(--dark);
            margin-bottom: 1.2rem;
        }
        form {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        input, textarea, select {
            padding: 0.8rem;
            border: 1px solid #ccc;
            border-radius: var(--radius);
            font-size: 1rem;
        }
        button {
            background-color: var(--primary);
            color: white;
            border: none;
            padding: 0.9rem 1.5rem;
            border-radius: var(--radius);
            font-weight: bold;
            cursor: pointer;
            transition: background 0.3s;
        }
        button:hover {
            background-color: var(--dark);
        }
        .stars {
            display: flex;
            gap: 5px;
            font-size: 1.8rem;
            color: #ddd;
            margin: 0.5rem 0;
        }
        .stars i {
            cursor: pointer;
            transition: color 0.2s;
        }
        .stars i:hover,
        .stars i.active {
            color: #FFD700;
        }
        footer {
            margin-top: 3rem;
            background-color: #263238;
            color: #eceff1;
            padding: 2.5rem;
            border-radius: var(--radius) var(--radius) 0 0;
            text-align: center;
        }
        friend-link {
            display: block;
            margin: 1.5rem 0;
        }
        .friend-links {
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: 1.5rem;
            margin: 2rem 0;
        }
        .friend-links a {
            color: #bbdefb;
            background: rgba(255,255,255,0.05);
            padding: 0.7rem 1.2rem;
            border-radius: 20px;
        }
        .friend-links a:hover {
            background: rgba(255,255,255,0.1);
            color: white;
        }
        .update-time {
            font-size: 0.9rem;
            color: #b0bec5;
            margin-top: 2rem;
        }
        @media (max-width: 900px) {
            .content-wrapper {
                grid-template-columns: 1fr;
            }
            nav ul {
                flex-direction: column;
                gap: 0;
                background: var(--dark);
                position: absolute;
                top: 100px;
                left: 0;
                width: 100%;
                padding: 1rem;
                border-radius: 0 0 var(--radius) var(--radius);
                display: none;
                z-index: 1000;
            }
            nav ul.show {
                display: flex;
            }
            .hamburger {
                display: block;
            }
            h1 {
                font-size: 2.2rem;
            }
            h2 {
                font-size: 1.8rem;
            }
        }
        @media (max-width: 600px) {
            main, aside {
                padding: 1.5rem;
            }
            header {
                padding: 1rem;
            }
            .my-logo {
                font-size: 1.8rem;
            }
        }
        .emoji {
            font-size: 1.2em;
            margin-right: 5px;
        }
        .key-term {
            font-weight: bold;
            color: var(--dark);
            background-color: #e8f5e9;
            padding: 2px 6px;
            border-radius: 4px;
        }
        .tip-box {
            background: #e3f2fd;
            border: 1px dashed #2196F3;
            padding: 1.2rem;
            border-radius: var(--radius);
            margin: 1.5rem 0;
        }