:root {
            --primary-color: #1a237e;
            --secondary-color: #ffab00;
            --accent-color: #d32f2f;
            --light-color: #f5f5f5;
            --dark-color: #121212;
            --text-color: #333;
            --text-light: #666;
            --border-color: #ddd;
            --shadow: 0 4px 12px rgba(0,0,0,0.1);
            --transition: all 0.3s ease;
            --max-width: 1200px;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: #f9f9f9;
            overflow-x: hidden;
        }
        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: var(--transition);
        }
        a:hover {
            color: var(--accent-color);
        }
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 20px;
        }
        header {
            background: linear-gradient(135deg, var(--primary-color), #283593);
            color: white;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        .header-top {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
        }
        .my-logo {
            font-size: 2.2rem;
            font-weight: 800;
            background: linear-gradient(to right, var(--secondary-color), #ffd740);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            text-transform: uppercase;
            letter-spacing: 1px;
        }
        .my-logo:hover {
            transform: scale(1.05);
        }
        .search-form {
            display: flex;
            flex-grow: 0.4;
            max-width: 400px;
        }
        .search-input {
            flex-grow: 1;
            padding: 10px 15px;
            border: none;
            border-radius: 25px 0 0 25px;
            font-size: 1rem;
            outline: none;
        }
        .search-button {
            background-color: var(--secondary-color);
            color: var(--dark-color);
            border: none;
            border-radius: 0 25px 25px 0;
            padding: 0 20px;
            cursor: pointer;
            font-weight: 600;
            transition: var(--transition);
        }
        .search-button:hover {
            background-color: #ffb300;
        }
        .hamburger {
            display: none;
            font-size: 1.8rem;
            cursor: pointer;
            background: none;
            border: none;
            color: white;
        }
        nav {
            background-color: rgba(0, 0, 0, 0.2);
        }
        .nav-links {
            display: flex;
            list-style: none;
            justify-content: center;
            padding: 10px 0;
        }
        .nav-links li {
            margin: 0 15px;
        }
        .nav-links a {
            color: white;
            font-weight: 500;
            padding: 8px 5px;
            border-bottom: 2px solid transparent;
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: var(--secondary-color);
            border-bottom-color: var(--secondary-color);
        }
        .breadcrumb {
            padding: 10px 0;
            background-color: #e8eaf6;
            font-size: 0.9rem;
            color: var(--text-light);
        }
        .breadcrumb a {
            color: var(--primary-color);
        }
        .breadcrumb a:hover {
            text-decoration: underline;
        }
        main {
            padding: 30px 0;
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 30px;
        }
        article {
            background-color: white;
            border-radius: 10px;
            padding: 30px;
            box-shadow: var(--shadow);
        }
        h1 {
            font-size: 2.8rem;
            color: var(--primary-color);
            margin-bottom: 15px;
            line-height: 1.2;
            border-bottom: 3px solid var(--secondary-color);
            padding-bottom: 15px;
        }
        .article-meta {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 25px;
            padding-bottom: 15px;
            border-bottom: 1px solid var(--border-color);
            color: var(--text-light);
            font-size: 0.9rem;
        }
        .update-time {
            color: var(--accent-color);
            font-weight: 600;
        }
        h2 {
            font-size: 2rem;
            color: var(--primary-color);
            margin: 35px 0 15px;
            padding-left: 10px;
            border-left: 5px solid var(--secondary-color);
        }
        h3 {
            font-size: 1.6rem;
            color: #3949ab;
            margin: 25px 0 10px;
        }
        h4 {
            font-size: 1.3rem;
            color: #5c6bc0;
            margin: 20px 0 10px;
        }
        p {
            margin-bottom: 18px;
            text-align: justify;
            hyphens: auto;
        }
        .intro {
            font-size: 1.2rem;
            color: var(--text-color);
            background-color: #e3f2fd;
            padding: 20px;
            border-radius: 8px;
            margin-bottom: 25px;
            border-left: 4px solid var(--primary-color);
        }
        .highlight {
            background-color: #fff9c4;
            padding: 15px;
            border-radius: 8px;
            margin: 20px 0;
            border: 1px dashed var(--secondary-color);
        }
        .content-img {
            width: 100%;
            max-width: 800px;
            height: auto;
            border-radius: 8px;
            margin: 25px auto;
            display: block;
            box-shadow: var(--shadow);
            transition: var(--transition);
        }
        .content-img:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 20px rgba(0,0,0,0.15);
        }
        .related-links {
            background-color: #f3e5f5;
            padding: 20px;
            border-radius: 8px;
            margin: 30px 0;
        }
        .related-links h3 {
            color: #7b1fa2;
            margin-top: 0;
        }
        .related-links ul {
            list-style: none;
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 10px;
        }
        .related-links li {
            padding: 8px 0;
            border-bottom: 1px dotted #ba68c8;
        }
        aside {
            display: flex;
            flex-direction: column;
            gap: 25px;
        }
        .sidebar-widget {
            background-color: white;
            border-radius: 10px;
            padding: 25px;
            box-shadow: var(--shadow);
        }
        .sidebar-widget h3 {
            color: var(--primary-color);
            margin-top: 0;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--border-color);
            margin-bottom: 20px;
        }
        .rating-widget {
            text-align: center;
        }
        .stars {
            font-size: 2rem;
            color: #ffc107;
            margin: 15px 0;
            letter-spacing: 5px;
        }
        .rating-form {
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        .rating-form select,
        .rating-form textarea {
            padding: 10px;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            font-family: inherit;
            width: 100%;
        }
        .rating-form button {
            background-color: var(--primary-color);
            color: white;
            border: none;
            padding: 12px;
            border-radius: 5px;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
        }
        .rating-form button:hover {
            background-color: var(--accent-color);
        }
        .comment {
            border-bottom: 1px solid var(--border-color);
            padding: 15px 0;
        }
        .comment:last-child {
            border-bottom: none;
        }
        .comment-author {
            font-weight: bold;
            color: var(--primary-color);
        }
        .comment-date {
            font-size: 0.8rem;
            color: var(--text-light);
        }
        .comment-form textarea {
            width: 100%;
            padding: 15px;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            margin-bottom: 15px;
            font-family: inherit;
            resize: vertical;
            min-height: 100px;
        }
        footer {
            background-color: var(--dark-color);
            color: #bbb;
            padding: 40px 0 20px;
            margin-top: 50px;
        }
        .footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 30px;
            margin-bottom: 30px;
        }
        .footer-logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--secondary-color);
            margin-bottom: 15px;
        }
        .footer-links h4 {
            color: #fff;
            margin-bottom: 20px;
            font-size: 1.2rem;
        }
        .footer-links ul {
            list-style: none;
        }
        .footer-links li {
            margin-bottom: 10px;
        }
        .footer-links a {
            color: #bbb;
        }
        .footer-links a:hover {
            color: var(--secondary-color);
            padding-left: 5px;
        }
        friend-link {
            display: block;
            background-color: #2c2c2c;
            padding: 20px;
            border-radius: 8px;
            margin: 20px 0;
            border-left: 4px solid var(--secondary-color);
        }
        friend-link a {
            color: #4fc3f7;
            font-weight: 600;
        }
        .copyright {
            text-align: center;
            padding-top: 20px;
            border-top: 1px solid #444;
            font-size: 0.9rem;
            color: #888;
        }
        @media (max-width: 992px) {
            main {
                grid-template-columns: 1fr;
            }
            .related-links ul {
                grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            }
        }
        @media (max-width: 768px) {
            .header-top {
                flex-wrap: wrap;
            }
            .search-form {
                order: 3;
                width: 100%;
                max-width: 100%;
                margin-top: 15px;
            }
            .hamburger {
                display: block;
            }
            .nav-links {
                flex-direction: column;
                display: none;
                background-color: var(--primary-color);
                position: absolute;
                top: 100%;
                left: 0;
                width: 100%;
                padding: 20px;
                box-shadow: var(--shadow);
            }
            .nav-links.active {
                display: flex;
            }
            .nav-links li {
                margin: 10px 0;
            }
            h1 {
                font-size: 2.2rem;
            }
            h2 {
                font-size: 1.8rem;
            }
            .intro {
                font-size: 1.1rem;
                padding: 15px;
            }
        }
        @media (max-width: 576px) {
            .container {
                padding: 0 15px;
            }
            article {
                padding: 20px;
            }
            .sidebar-widget {
                padding: 20px;
            }
            .related-links ul {
                grid-template-columns: 1fr;
            }
        }
        .tooltip {
            position: relative;
            display: inline-block;
            border-bottom: 1px dotted var(--primary-color);
            cursor: help;
        }
        .tooltip .tooltiptext {
            visibility: hidden;
            width: 200px;
            background-color: var(--primary-color);
            color: white;
            text-align: center;
            padding: 10px;
            border-radius: 6px;
            position: absolute;
            z-index: 1;
            bottom: 125%;
            left: 50%;
            margin-left: -100px;
            opacity: 0;
            transition: opacity 0.3s;
            font-size: 0.9rem;
        }
        .tooltip:hover .tooltiptext {
            visibility: visible;
            opacity: 1;
        }
        .btn {
            display: inline-block;
            background: linear-gradient(to right, var(--primary-color), #3949ab);
            color: white;
            padding: 12px 25px;
            border-radius: 25px;
            font-weight: 600;
            text-align: center;
            border: none;
            cursor: pointer;
            transition: var(--transition);
            box-shadow: 0 4px 8px rgba(26, 35, 126, 0.2);
        }
        .btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 15px rgba(26, 35, 126, 0.3);
            background: linear-gradient(to right, #3949ab, #303f9f);
        }
        .key-term {
            font-weight: bold;
            color: var(--accent-color);
        }
        .emoji {
            font-size: 1.2em;
            margin-right: 5px;
        }
        @media print {
            header, aside, footer, .breadcrumb, .article-meta, .related-links, .rating-widget, .comment-section, .search-form, .hamburger {
                display: none;
            }
            body {
                background-color: white;
                color: black;
                font-size: 12pt;
            }
            main {
                grid-template-columns: 1fr;
                padding: 0;
            }
            article {
                box-shadow: none;
                padding: 0;
            }
            a {
                color: black;
                text-decoration: underline;
            }
            h1, h2, h3, h4 {
                color: black;
            }
        }