/* roulang page: index */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --accent-color: #ffc107;
            --background-color: #f8f9fa;
            --text-color: #343a40;
            --light-text-color: #6c757d;
            --border-color: #dee2e6;
            --card-bg: #ffffff;
            --header-bg: #ffffff;
            --footer-bg: #343a40;
            --footer-text-color: #ffffff;
            --footer-link-color: #adb5bd;
            --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            --container-max-width: 1200px;
            --spacing-unit: 1rem;
            --border-radius: 0.25rem;
            --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
            --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
        }

        body {
            margin: 0;
            font-family: var(--font-family);
            background-color: var(--background-color);
            color: var(--text-color);
            line-height: 1.6;
            overflow-x: hidden;
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        a:hover {
            color: #0056b3;
            text-decoration: underline;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        .container {
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 var(--spacing-unit);
        }

        /* Header & Navigation */
        header {
            background-color: var(--header-bg);
            box-shadow: var(--shadow-sm);
            padding: var(--spacing-unit) 0;
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.75rem;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
        }
        .logo:hover {
            text-decoration: none;
        }

        .nav-links {
            display: flex;
            list-style: none;
            margin: 0;
            padding: 0;
        }

        .nav-links li {
            margin-left: calc(var(--spacing-unit) * 2);
        }

        .nav-links a {
            color: var(--text-color);
            font-weight: 500;
            padding: 0.5rem 0;
            position: relative;
            transition: color 0.3s ease;
        }

        .nav-links a:hover,
        .nav-links a.active {
            color: var(--primary-color);
            text-decoration: none;
        }

        .nav-links a:hover::after,
        .nav-links a.active::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 2px;
            background-color: var(--primary-color);
        }

        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 8) var(--spacing-unit);
            position: relative;
        }

        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
        }

        .hero-content {
            position: relative;
            z-index: 1;
        }

        .hero h1 {
            font-size: 3rem;
            margin-bottom: var(--spacing-unit);
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.25rem;
            margin-bottom: calc(var(--spacing-unit) * 3);
            color: rgba(255, 255, 255, 0.9);
        }

        .cta-button {
            display: inline-block;
            background-color: var(--accent-color);
            color: var(--text-color);
            padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2.5);
            font-size: 1.1rem;
            font-weight: bold;
            border-radius: var(--border-radius);
            transition: background-color 0.3s ease, transform 0.2s ease;
            box-shadow: var(--shadow-sm);
        }

        .cta-button:hover {
            background-color: #e0a800;
            text-decoration: none;
            transform: translateY(-2px);
        }

        /* Section Styles */
        .section {
            padding: calc(var(--spacing-unit) * 5) 0;
        }

        .section-title {
            text-align: center;
            font-size: 2.5rem;
            margin-bottom: calc(var(--spacing-unit) * 4);
            font-weight: bold;
            position: relative;
            padding-bottom: calc(var(--spacing-unit) * 1.5);
        }

        .section-title::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 60px;
            height: 3px;
            background-color: var(--primary-color);
            border-radius: 2px;
        }

        /* Feature Section */
        .features {
            background-color: #ffffff;
        }

        .feature-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: calc(var(--spacing-unit) * 3);
        }

        .feature-item {
            background-color: var(--card-bg);
            border-radius: var(--border-radius);
            padding: calc(var(--spacing-unit) * 3);
            box-shadow: var(--shadow-sm);
            text-align: center;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .feature-item:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }

        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: var(--spacing-unit);
        }

        .feature-item h3 {
            font-size: 1.5rem;
            margin-bottom: var(--spacing-unit);
            color: var(--text-color);
        }

        .feature-item p {
            color: var(--light-text-color);
        }

        /* Content List Section */
        .content-list {
            background-color: var(--background-color);
        }

        .content-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: calc(var(--spacing-unit) * 3);
        }

        .content-card {
            background-color: var(--card-bg);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: var(--shadow-sm);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            display: flex;
            flex-direction: column;
        }

        .content-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }

        .content-card img {
            width: 100%;
            height: 200px;
            object-fit: cover;
            transition: transform 0.3s ease;
        }

        .content-card:hover img {
            transform: scale(1.05);
        }

        .content-card-body {
            padding: calc(var(--spacing-unit) * 2);
            flex-grow: 1;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
        }

        .content-card h3 {
            font-size: 1.25rem;
            margin-bottom: var(--spacing-unit);
            color: var(--text-color);
        }

        .content-card-meta {
            font-size: 0.9rem;
            color: var(--light-text-color);
            margin-bottom: var(--spacing-unit);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .content-card-summary {
            font-size: 0.95rem;
            color: var(--light-text-color);
            margin-bottom: calc(var(--spacing-unit) * 2);
            flex-grow: 1;
        }

        .content-card-link {
            display: inline-block;
            background-color: var(--primary-color);
            color: #ffffff;
            padding: 0.6rem 1.2rem;
            border-radius: var(--border-radius);
            text-align: center;
            font-weight: bold;
            transition: background-color 0.3s ease;
            margin-top: auto; /* Push to bottom */
        }

        .content-card-link:hover {
            background-color: #0056b3;
            text-decoration: none;
        }

        .no-updates {
            text-align: center;
            font-size: 1.2rem;
            color: var(--light-text-color);
            padding: calc(var(--spacing-unit) * 4) 0;
        }

        /* Category Links Section */
        .category-links {
            background-color: #ffffff;
        }

        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: calc(var(--spacing-unit) * 2);
        }

        .category-item {
            background-color: var(--card-bg);
            border-radius: var(--border-radius);
            padding: calc(var(--spacing-unit) * 2);
            box-shadow: var(--shadow-sm);
            text-align: center;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .category-item:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }

        .category-item-icon {
            font-size: 2rem;
            color: var(--accent-color);
            margin-bottom: var(--spacing-unit);
        }

        .category-item h3 {
            font-size: 1.2rem;
            margin-bottom: 0.5rem;
            color: var(--text-color);
        }

        .category-item p {
            font-size: 0.9rem;
            color: var(--light-text-color);
        }

        /* FAQ Section */
        .faq-section {
            background-color: var(--background-color);
        }

        .faq-item {
            margin-bottom: var(--spacing-unit);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: var(--shadow-sm);
        }

        .faq-question {
            background-color: #ffffff;
            color: var(--primary-color);
            padding: var(--spacing-unit) calc(var(--spacing-unit) * 2);
            font-weight: bold;
            cursor: pointer;
            position: relative;
            transition: background-color 0.3s ease;
            border-bottom: 1px solid var(--border-color);
        }

        .faq-question:hover {
            background-color: #f1f3f5;
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: calc(var(--spacing-unit) * 2);
            font-size: 1.5rem;
            transition: transform 0.3s ease;
        }

        .faq-item.active .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
            background-color: var(--card-bg);
            padding: 0 calc(var(--spacing-unit) * 2);
            color: var(--light-text-color);
        }

        .faq-answer p {
            padding: var(--spacing-unit) 0;
            margin: 0;
        }

        /* CTA Section */
        .cta-section {
            background-color: var(--primary-color);
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 6) 0;
        }

        .cta-section h2 {
            font-size: 2.5rem;
            margin-bottom: calc(var(--spacing-unit) * 2);
        }

        .cta-section p {
            font-size: 1.1rem;
            margin-bottom: calc(var(--spacing-unit) * 3);
            color: rgba(255, 255, 255, 0.9);
        }

        /* Footer */
        footer {
            background-color: var(--footer-bg);
            color: var(--footer-text-color);
            padding: calc(var(--spacing-unit) * 4) 0 calc(var(--spacing-unit) * 2) 0;
            text-align: center;
            font-size: 0.9rem;
        }

        .footer-links {
            margin-bottom: var(--spacing-unit);
            padding: 0;
            list-style: none;
        }

        .footer-links li {
            display: inline-block;
            margin: 0 calc(var(--spacing-unit) * 1.5);
        }

        .footer-links a {
            color: var(--footer-link-color);
            transition: color 0.3s ease;
        }

        .footer-links a:hover {
            color: #ffffff;
            text-decoration: none;
        }

        .copyright {
            color: var(--footer-link-color);
            margin-top: var(--spacing-unit);
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .hero h1 {
                font-size: 2.5rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 2rem;
            }
            .content-grid {
                grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            }
        }

        @media (max-width: 768px) {
            nav {
                flex-direction: column;
                padding-bottom: var(--spacing-unit);
            }
            .logo {
                margin-bottom: var(--spacing-unit);
            }
            .nav-links {
                flex-direction: column;
                align-items: center;
                width: 100%;
            }
            .nav-links li {
                margin: 0.5rem 0;
            }
            .hero h1 {
                font-size: 2rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .feature-grid,
            .content-grid,
            .category-grid {
                grid-template-columns: 1fr;
            }
            .cta-section h2,
            .cta-section p {
                margin-left: var(--spacing-unit);
                margin-right: var(--spacing-unit);
            }
        }

        @media (max-width: 576px) {
            .hero {
                padding: calc(var(--spacing-unit) * 5) var(--spacing-unit);
            }
            .cta-button {
                padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 2);
                font-size: 1rem;
            }
            .section {
                padding: calc(var(--spacing-unit) * 3) 0;
            }
        }

/* roulang page: article */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --background-color: #f8f9fa;
            --text-color: #343a40;
            --weak-text-color: #6c757d;
            --border-color: #dee2e6;
            --border-radius-sm: 0.25rem;
            --border-radius-md: 0.5rem;
            --border-radius-lg: 1rem;
            --box-shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
            --box-shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
            --spacing-xs: 0.5rem;
            --spacing-sm: 1rem;
            --spacing-md: 1.5rem;
            --spacing-lg: 2rem;
            --font-size-base: 1rem;
            --font-size-lg: 1.25rem;
            --font-size-xl: 1.5rem;
            --font-size-h1: 2.5rem;
            --font-size-h2: 2rem;
            --font-size-h3: 1.75rem;
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: 'Helvetica Neue', Arial, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--background-color);
            padding-top: 80px; /* Space for fixed header */
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 var(--spacing-md);
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        a:hover {
            color: #0056b3;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        button,
        input,
        textarea {
            font-family: inherit;
            font-size: var(--font-size-base);
        }

        /* Header & Nav */
        header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background-color: rgba(255, 255, 255, 0.95);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            z-index: 1000;
            padding: var(--spacing-sm) 0;
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: var(--font-size-xl);
            font-weight: bold;
            color: var(--primary-color);
        }

        .nav-links {
            list-style: none;
            display: flex;
        }

        .nav-links li {
            margin-left: var(--spacing-lg);
        }

        .nav-links a {
            color: var(--text-color);
            font-weight: 500;
            padding: var(--spacing-xs) 0;
            position: relative;
        }

        .nav-links a.active,
        .nav-links a:hover {
            color: var(--primary-color);
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--primary-color);
            transition: width 0.3s ease;
        }

        .nav-links a:hover::after,
        .nav-links a.active::after {
            width: 100%;
        }

        /* Main Content Area */
        main {
            padding: var(--spacing-lg) 0;
        }

        .article-header {
            text-align: center;
            margin-bottom: var(--spacing-lg);
        }

        .article-header h1 {
            font-size: var(--font-size-h1);
            margin-bottom: var(--spacing-sm);
            color: var(--primary-color);
        }

        .article-meta {
            color: var(--weak-text-color);
            font-size: 0.9rem;
            margin-bottom: var(--spacing-md);
        }

        .article-content {
            background-color: #ffffff;
            padding: var(--spacing-lg);
            border-radius: var(--border-radius-md);
            box-shadow: var(--box-shadow-sm);
        }

        .article-content h2,
        .article-content h3,
        .article-content h4 {
            margin-bottom: var(--spacing-sm);
            color: var(--primary-color);
        }

        .article-content h2 {
            font-size: var(--font-size-h2);
        }

        .article-content h3 {
            font-size: var(--font-size-h3);
        }

        .article-content p {
            margin-bottom: var(--spacing-md);
        }

        .article-content ul,
        .article-content ol {
            margin-bottom: var(--spacing-md);
            padding-left: var(--spacing-lg);
        }

        .article-content strong {
            font-weight: bold;
        }

        .no-content {
            text-align: center;
            padding: var(--spacing-lg);
            font-size: var(--font-size-lg);
            color: var(--secondary-color);
        }

        .no-content a {
            display: inline-block;
            margin-top: var(--spacing-sm);
            padding: var(--spacing-sm) var(--spacing-md);
            background-color: var(--primary-color);
            color: #ffffff;
            border-radius: var(--border-radius-sm);
            transition: background-color 0.3s ease;
        }

        .no-content a:hover {
            background-color: #0056b3;
        }

        /* Section: Related Articles */
        .related-articles {
            margin-top: var(--spacing-lg);
            padding-top: var(--spacing-lg);
            border-top: 1px solid var(--border-color);
        }

        .related-articles h2 {
            text-align: center;
            margin-bottom: var(--spacing-lg);
            font-size: var(--font-size-h2);
            color: var(--primary-color);
        }

        .related-articles-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: var(--spacing-md);
        }

        .related-article-card {
            background-color: #ffffff;
            border-radius: var(--border-radius-md);
            box-shadow: var(--box-shadow-sm);
            overflow: hidden;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .related-article-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--box-shadow-md);
        }

        .related-article-card img {
            width: 100%;
            height: 180px;
            object-fit: cover;
        }

        .related-article-content {
            padding: var(--spacing-md);
        }

        .related-article-content h3 {
            font-size: var(--font-size-lg);
            margin-bottom: var(--spacing-sm);
            color: var(--primary-color);
        }

        .related-article-content p {
            font-size: 0.9rem;
            color: var(--weak-text-color);
            margin-bottom: var(--spacing-md);
        }

        .related-article-content .read-more {
            display: inline-block;
            color: var(--primary-color);
            font-weight: 500;
        }

        /* Footer */
        footer {
            background-color: var(--text-color);
            color: rgba(255, 255, 255, 0.8);
            padding: var(--spacing-lg) 0;
            margin-top: var(--spacing-lg);
            text-align: center;
        }

        .footer-links {
            list-style: none;
            display: flex;
            justify-content: center;
            margin-bottom: var(--spacing-md);
            flex-wrap: wrap;
        }

        .footer-links li {
            margin: 0 var(--spacing-md);
        }

        .footer-links a {
            color: rgba(255, 255, 255, 0.8);
            font-size: 0.9rem;
        }

        .footer-links a:hover {
            color: #ffffff;
        }

        .copyright {
            font-size: 0.9rem;
            color: rgba(255, 255, 255, 0.7);
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            body {
                padding-top: 70px;
            }

            nav {
                flex-direction: column;
                align-items: center;
            }

            .nav-links {
                margin-top: var(--spacing-sm);
                flex-direction: column;
                align-items: center;
                display: none; /* Hidden by default, shown via JS for mobile menu */
            }

            .nav-links.open {
                display: flex;
            }

            .nav-links li {
                margin: var(--spacing-xs) 0;
            }

            .logo {
                font-size: var(--font-size-lg);
            }

            .article-header h1 {
                font-size: var(--font-size-h2);
            }

            .article-content {
                padding: var(--spacing-md);
            }

            .related-articles-grid {
                grid-template-columns: 1fr;
            }

            .footer-links {
                flex-direction: column;
            }

            .footer-links li {
                margin: var(--spacing-xs) 0;
            }
        }

/* roulang page: category1 */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --accent-color: #28a745;
            --background-color: #f8f9fa;
            --card-background: #ffffff;
            --text-color: #343a40;
            --subtle-text-color: #6c757d;
            --border-color: #dee2e6;
            --border-radius: 8px;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --container-max-width: 1200px;
            --spacing-unit: 1rem;
            --header-height: 70px;
            --footer-height: 100px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Helvetica Neue', Arial, 'Liberation Sans', FreeSans, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background-color: var(--background-color);
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        a:hover {
            color: #0056b3;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        .container {
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 var(--spacing-unit);
            width: 100%;
        }

        /* Header */
        header {
            background-color: var(--card-background);
            padding: var(--spacing-unit) 0;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        header .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.8em;
            font-weight: bold;
            color: var(--primary-color);
        }

        .nav-links {
            list-style: none;
            display: flex;
        }

        .nav-links li {
            margin-left: calc(var(--spacing-unit) * 2);
        }

        .nav-links a {
            color: var(--text-color);
            font-weight: 500;
            padding: 0.5em 0;
            position: relative;
        }

        .nav-links a.active {
            color: var(--primary-color);
            font-weight: bold;
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--primary-color);
            transition: width 0.3s ease;
        }

        .nav-links a:hover::after {
            width: 100%;
        }

        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-3.webp');
            background-size: cover;
            background-position: center;
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 6) var(--spacing-unit);
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 400px; /* Adjust height as needed */
        }

        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.4));
            z-index: 1;
        }

        .hero .hero-content {
            position: relative;
            z-index: 2;
            max-width: 800px;
        }

        .hero h1 {
            font-size: 3em;
            margin-bottom: var(--spacing-unit);
            line-height: 1.3;
        }

        .hero p {
            font-size: 1.3em;
            margin-bottom: calc(var(--spacing-unit) * 2);
            opacity: 0.9;
        }

        .cta-button {
            display: inline-block;
            background-color: var(--accent-color);
            color: #ffffff;
            padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 3);
            font-size: 1.2em;
            font-weight: bold;
            border-radius: var(--border-radius);
            transition: background-color 0.3s ease, transform 0.2s ease;
            box-shadow: var(--shadow);
        }

        .cta-button:hover {
            background-color: #218838;
            transform: translateY(-2px);
        }

        /* Section */
        .section {
            padding: calc(var(--spacing-unit) * 5) 0;
        }

        .section h2 {
            text-align: center;
            font-size: 2.5em;
            margin-bottom: calc(var(--spacing-unit) * 3);
            color: var(--text-color);
        }

        /* Content Grid */
        .content-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: calc(var(--spacing-unit) * 2);
        }

        .content-card {
            background-color: var(--card-background);
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            overflow: hidden;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            display: flex;
            flex-direction: column;
        }

        .content-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
        }

        .content-card img {
            width: 100%;
            height: 200px; /* Fixed height for image consistency */
            object-fit: cover; /* Ensures image covers the area without distortion */
        }

        .content-card .card-content {
            padding: calc(var(--spacing-unit) * 1.5);
            flex-grow: 1; /* Allows content to take up available space */
        }

        .content-card h3 {
            font-size: 1.5em;
            margin-bottom: var(--spacing-unit);
            color: var(--primary-color);
        }

        .content-card p {
            font-size: 1em;
            margin-bottom: var(--spacing-unit);
            color: var(--subtle-text-color);
            line-height: 1.6;
        }

        .content-card .details {
            font-size: 0.9em;
            color: var(--subtle-text-color);
            margin-top: auto; /* Pushes details to the bottom */
        }

        /* Feature Section */
        .features .container {
            display: flex;
            flex-wrap: wrap;
            gap: calc(var(--spacing-unit) * 2);
            justify-content: center;
        }

        .feature-item {
            flex-basis: calc(33.333% - var(--spacing-unit)); /* Three columns */
            min-width: 250px;
            text-align: center;
            padding: var(--spacing-unit) * 2;
            background-color: var(--card-background);
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
        }

        .feature-item i { /* Placeholder for icons - assuming Font Awesome or similar */
            font-size: 3em;
            color: var(--accent-color);
            margin-bottom: var(--spacing-unit);
        }

        .feature-item h3 {
            font-size: 1.4em;
            margin-bottom: var(--spacing-unit) / 2;
            color: var(--text-color);
        }

        .feature-item p {
            font-size: 0.95em;
            color: var(--subtle-text-color);
        }

        /* FAQ Section */
        .faq-section .container {
            max-width: 800px;
        }

        .faq-item {
            background-color: var(--card-background);
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            margin-bottom: var(--spacing-unit);
            overflow: hidden;
        }

        .faq-question {
            padding: var(--spacing-unit) * 1.5;
            font-size: 1.2em;
            font-weight: bold;
            cursor: pointer;
            position: relative;
            background-color: var(--card-background);
            color: var(--text-color);
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-unit) * 1.5;
            font-size: 1.5em;
            transition: transform 0.3s ease;
        }

        .faq-item.active .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-in-out;
            padding: 0 var(--spacing-unit) * 1.5;
            background-color: #fdfdfd; /* Slightly different background for answer */
            font-size: 1em;
            color: var(--subtle-text-color);
        }

        .faq-item.active .faq-answer {
            max-height: 200px; /* Adjust as needed based on content length */
            padding: var(--spacing-unit) * 1.5;
        }

        /* CTA Section */
        .cta-section {
            background-color: var(--primary-color);
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 5) 0;
        }

        .cta-section h2 {
            font-size: 2.8em;
            margin-bottom: var(--spacing-unit);
            color: #ffffff;
        }

        .cta-section p {
            font-size: 1.2em;
            opacity: 0.9;
            margin-bottom: calc(var(--spacing-unit) * 2);
        }

        /* Footer */
        footer {
            background-color: #343a40;
            color: #ffffff;
            padding: calc(var(--spacing-unit) * 3) 0;
            margin-top: auto; /* Pushes footer to the bottom */
        }

        footer .container {
            text-align: center;
        }

        .footer-links {
            list-style: none;
            display: flex;
            justify-content: center;
            gap: calc(var(--spacing-unit) * 2);
            margin-bottom: var(--spacing-unit) * 2;
        }

        .footer-links a {
            color: #ffffff;
            font-weight: 500;
            transition: color 0.3s ease;
        }

        .footer-links a:hover {
            color: var(--accent-color);
        }

        .copyright {
            font-size: 0.9em;
            opacity: 0.7;
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .nav-links {
                display: none; /* Hide desktop nav, implement mobile menu separately if needed */
            }

            .hero h1 {
                font-size: 2.5em;
            }

            .hero p {
                font-size: 1.1em;
            }

            .feature-item {
                flex-basis: calc(50% - var(--spacing-unit));
            }
        }

        @media (max-width: 768px) {
            .hero {
                min-height: 300px;
                padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
            }

            .hero h1 {
                font-size: 2em;
            }

            .hero p {
                font-size: 1em;
            }

            .section h2 {
                font-size: 2em;
            }

            .content-grid {
                grid-template-columns: 1fr;
            }

            .feature-item {
                flex-basis: 100%;
            }

            .footer-links {
                flex-wrap: wrap;
                justify-content: center;
            }
        }

        @media (max-width: 576px) {
            .logo {
                font-size: 1.5em;
            }

            .hero {
                padding: calc(var(--spacing-unit) * 3) var(--spacing-unit);
                min-height: 250px;
            }

            .cta-button {
                padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 2);
                font-size: 1em;
            }

            .section {
                padding: calc(var(--spacing-unit) * 3) 0;
            }

            .section h2 {
                font-size: 1.8em;
                margin-bottom: calc(var(--spacing-unit) * 2);
            }

            .faq-question {
                font-size: 1.1em;
            }

            .cta-section h2 {
                font-size: 2em;
            }

            .cta-section p {
                font-size: 1.1em;
            }
        }

/* roulang page: category2 */
:root {
            --primary-color: #ff6f61;
            --secondary-color: #4a90e2;
            --background-color: #f4f7f6;
            --text-color: #333;
            --light-text-color: #666;
            --border-color: #e0e0e0;
            --card-background: #fff;
            --container-width: 1200px;
            --header-height: 80px;
            --footer-height: 100px;
            --spacing-unit: 16px;
            --radius-sm: 4px;
            --radius-md: 8px;
            --radius-lg: 12px;
            --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
            --shadow-md: 0 4px 8px rgba(0,0,0,0.1);
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'WenQuanYi Micro Hei', sans-serif;
            color: var(--text-color);
            background-color: var(--background-color);
            line-height: 1.7;
            scroll-behavior: smooth;
        }

        .container {
            max-width: var(--container-width);
            margin: 0 auto;
            padding: 0 calc(var(--spacing-unit) * 2);
        }

        a {
            color: var(--secondary-color);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        a:hover {
            color: var(--primary-color);
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        /* Header & Nav */
        header {
            background-color: var(--card-background);
            box-shadow: var(--shadow-sm);
            height: var(--header-height);
            display: flex;
            align-items: center;
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            width: 100%;
        }

        .logo {
            font-size: 1.8em;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
        }

        .nav-links {
            list-style: none;
            display: flex;
            gap: var(--spacing-unit) * 2.5;
        }

        .nav-links li a {
            color: var(--light-text-color);
            font-size: 1.1em;
            padding: var(--spacing-unit) 0;
            position: relative;
            transition: color 0.3s ease;
        }

        .nav-links li a.active,
        .nav-links li a:hover {
            color: var(--text-color);
        }

        .nav-links li a.active::after,
        .nav-links li a:hover::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 2px;
            background-color: var(--primary-color);
        }

        /* Hero Section */
        .hero {
            background-color: var(--secondary-color);
            color: #fff;
            padding: calc(var(--spacing-unit) * 8) 0;
            background-image: url('/assets/images/backpic/back-3.webp');
            background-size: cover;
            background-position: center;
            position: relative;
            text-align: center;
            overflow: hidden;
        }

        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5); /* Overlay for better text readability */
        }

        .hero .container {
            position: relative;
            z-index: 2;
        }

        .hero h1 {
            font-size: 3em;
            margin-bottom: var(--spacing-unit);
        }

        .hero p {
            font-size: 1.4em;
            margin-bottom: var(--spacing-unit) * 3;
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .hero .cta-button {
            display: inline-block;
            background-color: var(--primary-color);
            color: #fff;
            padding: var(--spacing-unit) * 2 calc(var(--spacing-unit) * 4);
            border-radius: var(--radius-lg);
            font-size: 1.2em;
            font-weight: bold;
            box-shadow: var(--shadow-md);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .hero .cta-button:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 12px rgba(0,0,0,0.2);
            color: #fff;
        }

        /* Section Styling */
        .section {
            padding: calc(var(--spacing-unit) * 6) 0;
        }

        .section h2 {
            font-size: 2.5em;
            text-align: center;
            margin-bottom: calc(var(--spacing-unit) * 4);
            position: relative;
        }

        .section h2::after {
            content: '';
            position: absolute;
            bottom: calc(var(--spacing-unit) * -2);
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 3px;
            background-color: var(--primary-color);
            border-radius: var(--radius-sm);
        }

        /* Feature Cards */
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: calc(var(--spacing-unit) * 3);
        }

        .feature-card {
            background-color: var(--card-background);
            border-radius: var(--radius-lg);
            padding: calc(var(--spacing-unit) * 3);
            text-align: center;
            box-shadow: var(--shadow-md);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 16px rgba(0,0,0,0.15);
        }

        .feature-card img {
            width: 60px;
            height: 60px;
            margin: 0 auto var(--spacing-unit) * 2;
            object-fit: contain;
        }

        .feature-card h3 {
            font-size: 1.5em;
            margin-bottom: var(--spacing-unit);
            color: var(--primary-color);
        }

        .feature-card p {
            font-size: 1em;
            color: var(--light-text-color);
        }

        /* Process Section */
        .process-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: calc(var(--spacing-unit) * 3);
            text-align: center;
        }

        .process-step {
            display: flex;
            flex-direction: column;
            align-items: center;
        }

        .process-step .icon {
            width: 70px;
            height: 70px;
            background-color: var(--primary-color);
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            color: #fff;
            font-size: 2em;
            font-weight: bold;
            margin-bottom: var(--spacing-unit) * 2;
            box-shadow: var(--shadow-md);
        }

        .process-step h3 {
            font-size: 1.3em;
            margin-bottom: var(--spacing-unit);
        }

        .process-step p {
            font-size: 1em;
            color: var(--light-text-color);
        }

        /* FAQ Section */
        .faq-list {
            max-width: 800px;
            margin: 0 auto;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            overflow: hidden;
        }

        .faq-item {
            border-bottom: 1px solid var(--border-color);
        }

        .faq-item:last-child {
            border-bottom: none;
        }

        .faq-question {
            background-color: #fdfdfd;
            padding: calc(var(--spacing-unit) * 2);
            font-size: 1.2em;
            font-weight: bold;
            cursor: pointer;
            position: relative;
            transition: background-color 0.3s ease;
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-unit) * 2;
            font-size: 1.5em;
            transition: transform 0.3s ease;
        }

        .faq-item.active .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-question:hover {
            background-color: #f9f9f9;
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
            background-color: var(--card-background);
        }

        .faq-answer p {
            padding: calc(var(--spacing-unit) * 2);
            color: var(--light-text-color);
        }

        /* CTA Section */
        .cta-section {
            background-color: var(--primary-color);
            color: #fff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 7) 0;
            position: relative;
            overflow: hidden;
        }

        .cta-section h2 {
            font-size: 2.8em;
            margin-bottom: var(--spacing-unit) * 2;
            color: #fff;
        }

        .cta-section p {
            font-size: 1.2em;
            margin-bottom: var(--spacing-unit) * 3;
            opacity: 0.9;
        }

        .cta-section .cta-button {
            display: inline-block;
            background-color: #fff;
            color: var(--primary-color);
            padding: var(--spacing-unit) * 2 calc(var(--spacing-unit) * 4);
            border-radius: var(--radius-lg);
            font-size: 1.2em;
            font-weight: bold;
            box-shadow: var(--shadow-md);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .cta-section .cta-button:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 12px rgba(255,255,255,0.4);
            color: var(--primary-color);
        }

        /* Footer */
        footer {
            background-color: #333;
            color: #ccc;
            padding: calc(var(--spacing-unit) * 4) 0 calc(var(--spacing-unit) * 3) 0;
            text-align: center;
            font-size: 0.9em;
        }

        .footer-links {
            list-style: none;
            display: flex;
            justify-content: center;
            gap: var(--spacing-unit) * 3;
            margin-bottom: var(--spacing-unit) * 3;
            flex-wrap: wrap;
        }

        .footer-links a {
            color: #ccc;
            transition: color 0.3s ease;
        }

        .footer-links a:hover {
            color: #fff;
        }

        .copyright {
            color: #aaa;
        }

        /* Responsive */
        @media (max-width: 1024px) {
            .container {
                padding: 0 var(--spacing-unit);
            }

            .hero h1 {
                font-size: 2.5em;
            }

            .hero p {
                font-size: 1.2em;
            }

            .section h2 {
                font-size: 2em;
            }
        }

        @media (max-width: 768px) {
            nav {
                flex-direction: column;
                align-items: flex-start;
            }

            .logo {
                margin-bottom: var(--spacing-unit) * 2;
            }

            .nav-links {
                flex-direction: column;
                gap: var(--spacing-unit);
                width: 100%;
                align-items: center;
            }
             .nav-links li {
                width: 100%;
                text-align: center;
            }

            .hero {
                padding: calc(var(--spacing-unit) * 6) 0;
            }

            .hero h1 {
                font-size: 2em;
            }

            .hero p {
                font-size: 1.1em;
                margin-bottom: var(--spacing-unit) * 2;
            }

            .hero .cta-button {
                padding: var(--spacing-unit) * 1.5 calc(var(--spacing-unit) * 3);
                font-size: 1em;
            }

            .section {
                padding: calc(var(--spacing-unit) * 4) 0;
            }

            .section h2 {
                font-size: 1.8em;
                margin-bottom: calc(var(--spacing-unit) * 3);
            }

            .features-grid, .process-grid {
                grid-template-columns: 1fr;
            }

            .feature-card, .process-step {
                padding: calc(var(--spacing-unit) * 2);
            }

            .faq-question {
                font-size: 1.1em;
            }

            .cta-section {
                padding: calc(var(--spacing-unit) * 5) 0;
            }

            .cta-section h2 {
                font-size: 2em;
            }

            .cta-section p {
                font-size: 1.1em;
            }

            .footer-links {
                flex-direction: column;
                gap: var(--spacing-unit);
            }
        }

/* roulang page: category3 */
/* CSS Variables */
        :root {
            --primary-color: #007bff; /* 品牌主色，用于链接、按钮、激活状态 */
            --secondary-color: #6c757d; /* 次要颜色，用于辅助元素 */
            --accent-color: #28a745; /* 强调色，用于CTA等 */
            --background-color: #f8f9fa; /* 页面背景色 */
            --card-background: #ffffff; /* 卡片背景色 */
            --text-color: #343a40; /* 主要文字颜色 */
            --muted-text-color: #6c757d; /* 弱化文字颜色 */
            --border-color: #dee2e6; /* 边框颜色 */
            --border-radius: 0.375rem; /* 标准圆角 */
            --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075); /* 小阴影 */
            --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.1); /* 中等阴影 */
            --container-max-width: 1140px;
            --spacing-1: 0.25rem;
            --spacing-2: 0.5rem;
            --spacing-3: 1rem;
            --spacing-4: 1.5rem;
            --spacing-5: 3rem;
            --font-family-sans: 'Helvetica Neue', Helvetica, Arial, sans-serif;
            --line-height-base: 1.6;
        }

        /* Reset & Base Styles */
        *, *::before, *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: var(--font-family-sans);
            line-height: var(--line-height-base);
            color: var(--text-color);
            background-color: var(--background-color);
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: color 0.2s ease-in-out;
        }

        a:hover {
            color: #0056b3;
            text-decoration: underline;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        .container {
            max-width: var(--container-max-width);
            margin-left: auto;
            margin-right: auto;
            padding-left: var(--spacing-3);
            padding-right: var(--spacing-3);
            width: 100%;
        }

        /* Header & Navigation */
        header {
            background-color: var(--card-background);
            box-shadow: var(--shadow-sm);
            padding: var(--spacing-3) 0;
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        header .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.5rem;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
        }

        .logo:hover {
            text-decoration: none;
        }

        .nav-links {
            list-style: none;
            display: flex;
            gap: var(--spacing-4);
        }

        .nav-links li a {
            color: var(--text-color);
            font-weight: 500;
            padding: var(--spacing-2) var(--spacing-3);
            border-radius: var(--border-radius);
            transition: background-color 0.2s ease-in-out, color 0.2s ease-in-out;
        }

        .nav-links li a.active,
        .nav-links li a:hover {
            background-color: var(--primary-color);
            color: #ffffff;
            text-decoration: none;
        }

        /* Hero Section */
        .hero {
            background-color: var(--primary-color);
            color: #ffffff;
            background-image: url('/assets/images/backpic/back-2.webp'); /* Placeholder */
            background-size: cover;
            background-position: center;
            padding: var(--spacing-5) 0;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5); /* Overlay for better text readability */
            z-index: 1;
        }

        .hero .container {
            position: relative;
            z-index: 2;
        }

        .hero h1 {
            font-size: 2.5rem;
            margin-bottom: var(--spacing-3);
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: var(--spacing-4);
            opacity: 0.9;
        }

        .btn {
            display: inline-block;
            background-color: var(--accent-color);
            color: #ffffff;
            padding: var(--spacing-3) var(--spacing-4);
            border-radius: var(--border-radius);
            font-weight: bold;
            text-decoration: none;
            transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
            border: none;
            cursor: pointer;
            font-size: 1.1rem;
        }

        .btn:hover {
            background-color: #218838;
            transform: translateY(-2px);
            text-decoration: none;
            box-shadow: var(--shadow-sm);
        }

        /* Content Sections */
        .section {
            padding: var(--spacing-5) 0;
        }

        .section h2 {
            font-size: 2rem;
            text-align: center;
            margin-bottom: var(--spacing-4);
            color: var(--primary-color);
        }

        .section-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: var(--spacing-4);
        }

        .card {
            background-color: var(--card-background);
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: var(--shadow-sm);
            transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
            display: flex;
            flex-direction: column;
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }

        .card img {
            width: 100%;
            height: 200px; /* Fixed height for cover images */
            object-fit: cover; /* Ensure cover images fill the space */
        }

        .card-body {
            padding: var(--spacing-4);
            flex-grow: 1; /* Allows card body to take available space */
            display: flex;
            flex-direction: column;
        }

        .card-title {
            font-size: 1.3rem;
            margin-bottom: var(--spacing-2);
            color: var(--primary-color);
        }

        .card-text {
            font-size: 0.95rem;
            color: var(--muted-text-color);
            margin-bottom: var(--spacing-3);
            flex-grow: 1;
        }

        .card-link {
            display: block;
            text-align: right;
            font-weight: bold;
        }

        /* Feature Section */
        .features .section-content {
            grid-template-columns: 1fr 1fr;
            align-items: center;
            gap: var(--spacing-5);
        }

        .features .section-content:nth-child(even) {
            grid-template-columns: 1fr 1fr; /* Keep order consistent */
        }

        .feature-image img {
            border-radius: var(--border-radius);
            box-shadow: var(--shadow-md);
        }

        .feature-text h3 {
            font-size: 1.8rem;
            margin-bottom: var(--spacing-3);
            color: var(--primary-color);
        }

        .feature-text p {
            font-size: 1rem;
            margin-bottom: var(--spacing-2);
            color: var(--muted-text-color);
        }

        /* FAQ Section */
        .faq .section-content {
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .faq-item {
            background-color: var(--card-background);
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            margin-bottom: var(--spacing-3);
        }

        .faq-question {
            padding: var(--spacing-3) var(--spacing-4);
            font-weight: bold;
            cursor: pointer;
            position: relative;
            background-color: var(--card-background);
            border-radius: var(--border-radius);
            transition: background-color 0.2s ease-in-out;
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-4);
            font-size: 1.5rem;
            transition: transform 0.2s ease-in-out;
        }

        .faq-item.open .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-answer {
            padding: 0 var(--spacing-4);
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-in-out, padding 0.3s ease-in-out;
            background-color: var(--background-color);
            border-top: 1px solid var(--border-color);
            border-radius: 0 0 var(--border-radius) var(--border-radius);
        }

        .faq-item.open .faq-answer {
            max-height: 200px; /* Adjust as needed */
            padding: var(--spacing-3) var(--spacing-4);
        }

        .faq-answer p {
            margin-bottom: 0;
        }

        /* CTA Section */
        .cta {
            background-color: var(--primary-color);
            color: #ffffff;
            text-align: center;
            padding: var(--spacing-5) 0;
            position: relative;
            overflow: hidden;
        }

        .cta::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.4);
            z-index: 1;
        }

        .cta .container {
            position: relative;
            z-index: 2;
        }

        .cta h2 {
            font-size: 2rem;
            margin-bottom: var(--spacing-3);
            color: #ffffff;
        }

        .cta p {
            font-size: 1.1rem;
            margin-bottom: var(--spacing-4);
            opacity: 0.9;
        }

        .cta .btn {
            background-color: var(--accent-color);
        }

        .cta .btn:hover {
            background-color: #218838;
        }

        /* Footer */
        footer {
            background-color: #343a40;
            color: #ffffff;
            padding: var(--spacing-5) 0;
            margin-top: auto; /* Pushes footer to the bottom */
            font-size: 0.9rem;
        }

        footer .container {
            text-align: center;
        }

        .footer-links {
            list-style: none;
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: var(--spacing-4);
            margin-bottom: var(--spacing-3);
        }

        .footer-links li a {
            color: #ffffff;
            opacity: 0.8;
            transition: opacity 0.2s ease-in-out;
        }

        .footer-links li a:hover {
            opacity: 1;
            text-decoration: underline;
        }

        .copyright {
            margin-bottom: 0;
            opacity: 0.7;
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .nav-links {
                gap: var(--spacing-3);
            }

            .hero h1 {
                font-size: 2.2rem;
            }

            .hero p {
                font-size: 1.1rem;
            }

            .section h2 {
                font-size: 1.8rem;
            }

            .features .section-content {
                grid-template-columns: 1fr;
            }
        }

        @media (max-width: 768px) {
            header .container {
                flex-direction: column;
                gap: var(--spacing-3);
            }

            nav {
                width: 100%;
                display: flex;
                justify-content: center;
            }

            .nav-links {
                display: none; /* Hidden by default, would use a burger menu */
                flex-direction: column;
                position: absolute;
                top: 70px; /* Adjust based on header height */
                left: 0;
                width: 100%;
                background-color: var(--card-background);
                box-shadow: var(--shadow-sm);
                padding: var(--spacing-3);
                gap: 0;
            }

            .nav-links li {
                text-align: center;
                margin-bottom: var(--spacing-2);
            }

            .nav-links li a {
                display: block;
                padding: var(--spacing-3);
            }

            .hero {
                padding: var(--spacing-4) 0;
            }

            .hero h1 {
                font-size: 2rem;
            }

            .hero p {
                font-size: 1rem;
            }

            .section {
                padding: var(--spacing-4) 0;
            }

            .section-content {
                grid-template-columns: 1fr;
            }

            .card img {
                height: 180px;
            }

            .footer-links {
                flex-direction: column;
                gap: var(--spacing-2);
            }
        }

        @media (max-width: 576px) {
            .logo {
                font-size: 1.3rem;
            }

            .hero h1 {
                font-size: 1.8rem;
            }

            .btn {
                padding: var(--spacing-2) var(--spacing-3);
                font-size: 1rem;
            }

            .section h2 {
                font-size: 1.6rem;
            }

            .card-body {
                padding: var(--spacing-3);
            }

            .feature-text h3 {
                font-size: 1.5rem;
            }
        }

/* roulang page: category4 */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --background-color: #f8f9fa;
            --text-color: #212529;
            --muted-text-color: #495057;
            --border-color: #dee2e6;
            --card-background: #ffffff;
            --button-hover-bg: #0056b3;
            --button-hover-text: #ffffff;
            --nav-background: #ffffff;
            --footer-background: #343a40;
            --footer-text-color: #adb5bd;
            --footer-link-color: #ffffff;
            --footer-link-hover-color: #dee2e6;
            --container-max-width: 1200px;
            --container-padding: 15px;
            --spacing-xs: 8px;
            --spacing-sm: 12px;
            --spacing-md: 20px;
            --spacing-lg: 30px;
            --spacing-xl: 40px;
            --border-radius-sm: 4px;
            --border-radius-md: 8px;
            --border-radius-lg: 12px;
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
            --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
            --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
        }

        *, *::before, *::after {
            box-sizing: border-box;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            margin: 0;
            font-family: var(--font-family);
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--background-color);
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        .container {
            width: 100%;
            max-width: var(--container-max-width);
            margin-left: auto;
            margin-right: auto;
            padding-left: var(--container-padding);
            padding-right: var(--container-padding);
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: color 0.2s ease-in-out;
        }

        a:hover {
            color: var(--button-hover-bg);
            text-decoration: underline;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        button {
            font-family: var(--font-family);
            cursor: pointer;
            border: none;
            border-radius: var(--border-radius-sm);
            transition: background-color 0.2s ease-in-out, color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
        }

        h1, h2, h3, h4, h5, h6 {
            margin-top: 0;
            margin-bottom: var(--spacing-md);
            line-height: 1.3;
            font-weight: 600;
        }

        h1 { font-size: 2.5rem; }
        h2 { font-size: 2rem; }
        h3 { font-size: 1.75rem; }
        h4 { font-size: 1.5rem; }
        h5 { font-size: 1.25rem; }
        h6 { font-size: 1rem; }

        header {
            background-color: var(--nav-background);
            padding: var(--spacing-md) 0;
            box-shadow: var(--shadow-sm);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        header nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        header .logo {
            font-size: 1.8rem;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
        }

        header .logo:hover {
            text-decoration: none;
        }

        .nav-links {
            list-style: none;
            margin: 0;
            padding: 0;
            display: flex;
        }

        .nav-links li {
            margin-left: var(--spacing-lg);
        }

        .nav-links a {
            color: var(--text-color);
            font-weight: 500;
            padding: var(--spacing-sm) 0;
            position: relative;
            transition: color 0.2s ease-in-out;
        }

        .nav-links a:hover, .nav-links a.active {
            color: var(--primary-color);
        }

        .nav-links a.active::after, .nav-links a:hover::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 2px;
            background-color: var(--primary-color);
        }

        .hero {
            background-image: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('/assets/images/backpic/back-2.webp');
            background-size: cover;
            background-position: center;
            color: #ffffff;
            padding: var(--spacing-xl) 0;
            text-align: center;
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 50vh;
        }

        .hero-content {
            max-width: 800px;
            margin: 0 auto;
        }

        .hero h1 {
            font-size: 3rem;
            margin-bottom: var(--spacing-md);
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: var(--spacing-lg);
            color: rgba(255, 255, 255, 0.9);
        }

        .cta-button {
            display: inline-block;
            background-color: var(--primary-color);
            color: #ffffff;
            padding: var(--spacing-sm) var(--spacing-lg);
            border-radius: var(--border-radius-sm);
            font-size: 1.1rem;
            font-weight: bold;
            transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
        }

        .cta-button:hover {
            background-color: var(--button-hover-bg);
            text-decoration: none;
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }

        main .section {
            padding: var(--spacing-xl) 0;
        }

        main .section h2 {
            text-align: center;
            margin-bottom: var(--spacing-lg);
            font-size: 2.2rem;
        }

        .card-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: var(--spacing-lg);
        }

        .card {
            background-color: var(--card-background);
            border-radius: var(--border-radius-md);
            box-shadow: var(--shadow-sm);
            overflow: hidden;
            transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
            display: flex;
            flex-direction: column;
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-md);
        }

        .card img {
            width: 100%;
            height: 200px;
            object-fit: cover;
        }

        .card-content {
            padding: var(--spacing-md);
            flex-grow: 1;
            display: flex;
            flex-direction: column;
        }

        .card-content h3 {
            font-size: 1.4rem;
            margin-bottom: var(--spacing-sm);
        }

        .card-content p {
            color: var(--muted-text-color);
            font-size: 0.95rem;
            flex-grow: 1;
            margin-bottom: var(--spacing-md);
        }

        .card-footer {
            padding: var(--spacing-md);
            margin-top: auto;
            text-align: right;
        }

        .card-footer .cta-button {
            font-size: 1rem;
            padding: var(--spacing-sm) var(--spacing-md);
        }

        .features-section ul {
            list-style: none;
            padding: 0;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: var(--spacing-md);
        }

        .features-section li {
            display: flex;
            align-items: flex-start;
            gap: var(--spacing-sm);
        }

        .features-section li::before {
            content: '✔';
            color: var(--primary-color);
            font-weight: bold;
            font-size: 1.2rem;
            flex-shrink: 0;
        }

        .faq-section {
            background-color: var(--card-background);
            padding: var(--spacing-xl) 0;
        }

        .faq-section h2 {
            margin-bottom: var(--spacing-lg);
        }

        .faq-item {
            margin-bottom: var(--spacing-md);
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius-md);
        }

        .faq-question {
            background-color: #f1f3f5;
            padding: var(--spacing-md);
            font-weight: bold;
            cursor: pointer;
            position: relative;
            border-radius: var(--border-radius-md) var(--border-radius-md) 0 0;
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-md);
            font-size: 1.5rem;
            transition: transform 0.2s ease-in-out;
        }

        .faq-item.active .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
            padding: 0 var(--spacing-md);
            border-radius: 0 0 var(--border-radius-md) var(--border-radius-md);
        }

        .faq-answer p {
            padding-top: var(--spacing-md);
            padding-bottom: var(--spacing-md);
            margin-bottom: 0;
        }

        .faq-item.active .faq-answer {
            max-height: 200px; /* Adjust as needed */
            padding-left: var(--spacing-md);
            padding-right: var(--spacing-md);
        }

        footer {
            background-color: var(--footer-background);
            color: var(--footer-text-color);
            padding: var(--spacing-xl) 0;
            margin-top: auto;
            text-align: center;
        }

        footer .footer-links {
            list-style: none;
            padding: 0;
            margin-bottom: var(--spacing-md);
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: var(--spacing-md);
        }

        footer .footer-links li {
            margin: 0;
        }

        footer .footer-links a {
            color: var(--footer-link-color);
            text-decoration: none;
            font-weight: 500;
        }

        footer .footer-links a:hover {
            color: var(--footer-link-hover-color);
            text-decoration: underline;
        }

        footer .copyright {
            font-size: 0.9rem;
            margin-bottom: 0;
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .nav-links {
                display: none; /* Hide desktop nav, implement mobile menu if needed */
            }

            .hero h1 {
                font-size: 2.5rem;
            }

            .hero p {
                font-size: 1.1rem;
            }

            .card-grid {
                grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            }
        }

        @media (max-width: 768px) {
            h1 { font-size: 2rem; }
            h2 { font-size: 1.75rem; }

            .hero {
                min-height: 40vh;
            }

            .hero h1 {
                font-size: 2.2rem;
            }

            .card-grid {
                grid-template-columns: 1fr;
            }
            
            .features-section ul {
                grid-template-columns: 1fr;
            }
        }

        @media (max-width: 576px) {
            .hero h1 {
                font-size: 1.8rem;
            }

            .hero p {
                font-size: 1rem;
            }

            .cta-button {
                padding: var(--spacing-sm) var(--spacing-md);
                font-size: 1rem;
            }
        }