/* roulang page: index */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --background-color: #f8f9fa;
            --text-color: #212529;
            --muted-text-color: #495057;
            --border-color: #dee2e6;
            --border-radius: 0.375rem;
            --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
            --spacing-unit: 1rem;
            --container-max-width: 1200px;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--background-color);
            scroll-behavior: smooth;
        }

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

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

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

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

        .header {
            background-color: #ffffff;
            padding: calc(var(--spacing-unit) * 0.75) 0;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
        }

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

        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--primary-color);
            letter-spacing: -1px;
        }

        .logo span {
            color: var(--muted-text-color);
            font-weight: 500;
        }

        .main-nav ul {
            list-style: none;
            display: flex;
            gap: calc(var(--spacing-unit) * 1.5);
        }

        .main-nav a {
            font-size: 1.1rem;
            font-weight: 500;
            color: var(--text-color);
            padding: 0.5rem 0;
            position: relative;
        }

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

        .main-nav a.active {
            color: var(--primary-color);
            font-weight: 600;
        }

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

        .main-nav a:hover::after,
        .main-nav a:focus::after {
            width: 100%;
        }

        .mobile-nav-toggle {
            display: none;
            font-size: 1.8rem;
            background: none;
            border: none;
            color: var(--text-color);
            cursor: pointer;
        }

        @media (max-width: 768px) {
            .main-nav ul {
                display: none;
                position: absolute;
                top: 100%;
                left: 0;
                right: 0;
                background-color: #ffffff;
                flex-direction: column;
                text-align: center;
                padding: var(--spacing-unit) 0;
                box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
            }
            .main-nav ul.active {
                display: flex;
            }
            .main-nav li {
                margin: var(--spacing-unit) 0;
            }
            .mobile-nav-toggle {
                display: block;
            }
        }

        .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) * 6) 0;
            position: relative;
        }

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

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

        .hero h1 {
            font-size: 3rem;
            margin-bottom: calc(var(--spacing-unit) * 0.75);
            font-weight: 700;
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.3rem;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            font-weight: 400;
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .btn {
            display: inline-block;
            background-color: var(--primary-color);
            color: #ffffff;
            padding: calc(var(--spacing-unit) * 0.75) calc(var(--spacing-unit) * 1.5);
            border-radius: var(--border-radius);
            font-size: 1.1rem;
            font-weight: 500;
            transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
            border: none;
            cursor: pointer;
        }

        .btn:hover, .btn:focus {
            background-color: #0056b3;
            color: #ffffff;
            text-decoration: none;
            transform: translateY(-2px);
            box-shadow: var(--box-shadow);
        }

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

        .section-title {
            text-align: center;
            font-size: 2.5rem;
            margin-bottom: calc(var(--spacing-unit) * 2);
            font-weight: 700;
            line-height: 1.3;
        }

        .section-subtitle {
            text-align: center;
            font-size: 1.2rem;
            color: var(--muted-text-color);
            margin-bottom: calc(var(--spacing-unit) * 2.5);
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .card-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: calc(var(--spacing-unit) * 2);
        }

        .card {
            background-color: #ffffff;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            overflow: hidden;
            transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
        }

        .card:hover, .card:focus-within {
            transform: translateY(-5px);
            box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
        }

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

        .card-content {
            padding: calc(var(--spacing-unit) * 1.25);
        }

        .card-title {
            font-size: 1.4rem;
            margin-bottom: calc(var(--spacing-unit) * 0.5);
            font-weight: 600;
            color: var(--primary-color);
        }
        
        .card-title a {
            color: var(--primary-color);
            text-decoration: none;
        }

        .card-title a:hover, .card-title a:focus {
            text-decoration: underline;
        }

        .card-excerpt {
            font-size: 1rem;
            color: var(--muted-text-color);
            margin-bottom: var(--spacing-unit);
        }

        .card-meta {
            font-size: 0.9rem;
            color: var(--secondary-color);
            margin-bottom: calc(var(--spacing-unit) * 0.75);
        }

        .card-category {
            display: inline-block;
            background-color: var(--primary-color);
            color: #ffffff;
            padding: 0.25rem 0.75rem;
            border-radius: var(--border-radius);
            font-size: 0.85rem;
            font-weight: 500;
            margin-bottom: var(--spacing-unit);
        }

        .cta-section {
            background-color: var(--primary-color);
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 4) 0;
        }

        .cta-section h2 {
            font-size: 2.8rem;
            margin-bottom: calc(var(--spacing-unit) * 1);
            font-weight: 700;
        }

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

        .cta-section .btn {
            background-color: #ffffff;
            color: var(--primary-color);
            font-weight: 600;
        }

        .cta-section .btn:hover, .cta-section .btn:focus {
            background-color: #e9ecef;
            color: #003f7f;
        }

        .faq-section {
            background-color: #ffffff;
        }

        .faq-section .section-title {
            color: var(--primary-color);
        }

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

        .faq-question {
            padding: var(--spacing-unit);
            font-size: 1.2rem;
            font-weight: 500;
            cursor: pointer;
            background-color: #f1f3f5;
            border-radius: var(--border-radius) var(--border-radius) 0 0;
            position: relative;
            transition: background-color 0.2s ease-in-out;
        }

        .faq-question:hover {
            background-color: #e9ecef;
        }

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

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

        .faq-answer {
            padding: 0 var(--spacing-unit);
            font-size: 1rem;
            color: var(--muted-text-color);
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-in-out, padding 0.3s ease-in-out;
        }

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

        .footer {
            background-color: var(--text-color);
            color: #ffffff;
            padding: calc(var(--spacing-unit) * 2) 0;
            text-align: center;
            font-size: 0.9rem;
        }

        .footer .container {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--spacing-unit);
        }

        .footer-nav a {
            color: #ffffff;
            margin: 0 0.75rem;
        }
        
        .footer-nav a:hover, .footer-nav a:focus {
            color: #cccccc;
        }

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

        /* Responsive Adjustments */
        @media (max-width: 992px) {
            .hero h1 {
                font-size: 2.5rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 2.2rem;
            }
            .card-grid {
                grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            }
        }

        @media (max-width: 768px) {
            .hero {
                padding: calc(var(--spacing-unit) * 4) 0;
            }
            .hero h1 {
                font-size: 2.2rem;
            }
            .hero p {
                font-size: 1rem;
                margin-bottom: calc(var(--spacing-unit) * 1.25);
            }
            .section-title {
                font-size: 2rem;
                margin-bottom: calc(var(--spacing-unit) * 1.5);
            }
            .section-subtitle {
                font-size: 1.1rem;
            }
            .card-grid {
                grid-template-columns: 1fr;
            }
            .cta-section h2 {
                font-size: 2.2rem;
            }
            .cta-section p {
                font-size: 1.1rem;
            }
            .faq-question {
                font-size: 1.1rem;
            }
        }

/* roulang page: article */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --background-color: #f8f9fa;
            --text-color: #212529;
            --muted-text-color: #6c757d;
            --border-color: #dee2e6;
            --border-radius: 0.375rem;
            --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
            --spacing-unit: 1rem;
            --container-max-width: 1140px;
            --nav-height: 60px;
            --footer-height: 80px;
        }

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

        html {
            font-size: 16px;
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--background-color);
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            margin-top: var(--nav-height); /* 确保内容不被导航遮挡 */
            padding-bottom: var(--footer-height); /* 确保内容不被页脚遮挡 */
            position: relative;
            min-height: calc(100vh - var(--nav-height) - var(--footer-height));
        }

        .container {
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 calc(var(--spacing-unit) * 1.5);
        }

        .main-nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: var(--nav-height);
            background-color: rgba(255, 255, 255, 0.95);
            box-shadow: 0 1px 5px rgba(0, 0, 0, 0.1);
            z-index: 1000;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 calc(var(--spacing-unit) * 1.5);
        }

        .main-nav .logo {
            font-size: 1.5rem;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
            margin-right: var(--spacing-unit);
            white-space: nowrap;
        }

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

        .main-nav li {
            margin-left: var(--spacing-unit);
        }

        .main-nav a {
            text-decoration: none;
            color: var(--text-color);
            font-weight: 500;
            padding: 0.5rem 0.75rem;
            border-radius: var(--border-radius);
            transition: all 0.3s ease;
            position: relative;
        }

        .main-nav a:hover,
        .main-nav a.active {
            color: var(--primary-color);
            background-color: rgba(0, 123, 255, 0.1);
        }

        .main-nav a.active::after {
            content: '';
            position: absolute;
            bottom: 0.25rem;
            left: 50%;
            transform: translateX(-50%);
            width: 75%;
            height: 2px;
            background-color: var(--primary-color);
        }

        .hero {
            position: relative;
            height: 60vh;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            color: #fff;
            background-image: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            border-radius: var(--border-radius);
            margin-bottom: calc(var(--spacing-unit) * 2);
            overflow: hidden;
        }

        .hero-content {
            position: relative;
            z-index: 1;
            max-width: 800px;
        }

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

        .hero p {
            font-size: 1.2rem;
            margin-bottom: calc(var(--spacing-unit) * 2);
            color: rgba(255, 255, 255, 0.9);
        }

        .btn {
            display: inline-block;
            padding: 0.75rem 1.5rem;
            font-size: 1rem;
            font-weight: bold;
            text-decoration: none;
            border-radius: var(--border-radius);
            transition: all 0.3s ease;
            cursor: pointer;
            border: none;
        }

        .btn-primary {
            background-color: var(--primary-color);
            color: #fff;
            box-shadow: var(--box-shadow);
        }

        .btn-primary:hover {
            background-color: #0056b3;
            transform: translateY(-2px);
            box-shadow: 0 0.25rem 0.5rem rgba(0, 123, 255, 0.3);
        }

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

        .section h2 {
            font-size: 2.2rem;
            text-align: center;
            margin-bottom: calc(var(--spacing-unit) * 2);
            color: var(--primary-color);
        }

        .article-content {
            background-color: #fff;
            padding: calc(var(--spacing-unit) * 3);
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            margin-top: calc(var(--spacing-unit) * 2);
        }

        .article-content h3 {
            font-size: 1.8rem;
            margin-bottom: var(--spacing-unit);
            color: var(--text-color);
        }

        .article-content p {
            margin-bottom: var(--spacing-unit);
            color: var(--muted-text-color);
            font-size: 1.05rem;
        }

        .article-content img {
            max-width: 100%;
            height: auto;
            display: block;
            margin: calc(var(--spacing-unit) * 1.5) auto;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
        }

        .article-meta {
            font-size: 0.9rem;
            color: var(--muted-text-color);
            margin-bottom: calc(var(--spacing-unit) * 2);
            display: flex;
            flex-wrap: wrap;
            gap: var(--spacing-unit);
        }

        .article-meta span {
            margin-right: var(--spacing-unit);
        }

        .no-content {
            text-align: center;
            padding: calc(var(--spacing-unit) * 3) 0;
            color: var(--muted-text-color);
        }

        .no-content p {
            font-size: 1.2rem;
            margin-bottom: var(--spacing-unit);
        }

        .btn-back-home {
            background-color: var(--secondary-color);
            color: #fff;
        }

        .btn-back-home:hover {
            background-color: #5a6268;
        }

        .footer {
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: var(--footer-height);
            background-color: #343a40;
            color: rgba(255, 255, 255, 0.7);
            padding: var(--spacing-unit) 0;
            text-align: center;
            margin-top: calc(var(--spacing-unit) * 2);
        }

        .footer .container {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            height: 100%;
        }

        .footer-nav {
            margin-bottom: calc(var(--spacing-unit) * 0.5);
        }

        .footer-nav a {
            color: rgba(255, 255, 255, 0.9);
            text-decoration: none;
            margin: 0 var(--spacing-unit);
            transition: color 0.3s ease;
        }

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

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

        /* 响应式设计 */
        @media (max-width: 992px) {
            .main-nav ul {
                display: none; /* 移动端菜单需要额外实现，此处隐藏 */
            }

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

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

        @media (max-width: 768px) {
            .hero {
                height: 50vh;
            }
            .hero h1 {
                font-size: 2.2rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            .article-content {
                padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
            }
        }

        @media (max-width: 576px) {
            .main-nav .logo {
                font-size: 1.3rem;
            }
            .hero h1 {
                font-size: 1.8rem;
                line-height: 1.3;
            }
            .hero p {
                font-size: 1rem;
            }
            .btn {
                padding: 0.6rem 1.2rem;
                font-size: 0.9rem;
            }
            .section {
                padding: calc(var(--spacing-unit) * 2) 0;
            }
            .section h2 {
                font-size: 1.7rem;
            }
            .footer-nav a {
                margin: 0 0.5rem;
            }
        }

/* roulang page: category1 */
:root {
            --primary-color: #ff6b6b;
            --secondary-color: #48dbfb;
            --background-light: #f8f9fa;
            --background-dark: #343a40;
            --text-color: #212529;
            --text-muted: #6c757d;
            --border-color: #dee2e6;
            --card-bg: #ffffff;
            --button-hover-bg: #e95454;
            --button-hover-text: #ffffff;
            --container-max-width: 1200px;
            --spacing-unit: 1rem;
            --border-radius: 0.5rem;
            --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
            --header-height: 70px;
            --footer-height: 100px;
        }

        html {
            scroll-behavior: smooth;
            box-sizing: border-box;
        }

        *, *:before, *:after {
            box-sizing: inherit;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
            line-height: 1.7;
            color: var(--text-color);
            background-color: var(--background-light);
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        .container {
            width: 90%;
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 var(--spacing-unit);
        }

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

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

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

        .btn {
            display: inline-block;
            padding: 0.75rem 1.5rem;
            font-size: 1rem;
            font-weight: 600;
            border-radius: var(--border-radius);
            cursor: pointer;
            transition: background-color 0.3s ease, color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
            text-align: center;
            white-space: nowrap;
        }

        .btn-primary {
            background-color: var(--primary-color);
            color: #ffffff;
            border: none;
            box-shadow: 0 4px 10px rgba(255, 107, 107, 0.3);
        }

        .btn-primary:hover {
            background-color: var(--button-hover-bg);
            color: var(--button-hover-text);
            transform: translateY(-2px);
            box-shadow: 0 6px 15px rgba(233, 84, 84, 0.4);
        }

        .btn-secondary {
            background-color: transparent;
            color: var(--primary-color);
            border: 2px solid var(--primary-color);
        }

        .btn-secondary:hover {
            background-color: var(--primary-color);
            color: #ffffff;
        }

        .badge {
            display: inline-block;
            padding: 0.3rem 0.8rem;
            font-size: 0.85rem;
            font-weight: 600;
            border-radius: 1rem;
            background-color: var(--primary-color);
            color: #ffffff;
            margin-right: var(--spacing-unit);
        }

        .section-title {
            font-size: 2.5rem;
            font-weight: 700;
            text-align: center;
            margin-bottom: calc(var(--spacing-unit) * 3);
            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;
        }

        .card {
            background-color: var(--card-bg);
            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;
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
        }

        .card-image {
            width: 100%;
            height: 200px;
            object-fit: cover;
            background-size: cover;
            background-position: center;
        }

        .card-content {
            padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
            flex-grow: 1;
            display: flex;
            flex-direction: column;
        }

        .card-title {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: calc(var(--spacing-unit) * 0.75);
            color: var(--text-color);
        }

        .card-description {
            font-size: 0.95rem;
            color: var(--text-muted);
            margin-bottom: var(--spacing-unit);
            flex-grow: 1;
        }
        
        .card-tags {
            margin-top: auto;
            padding-top: var(--spacing-unit);
        }

        .card-tags span {
            display: inline-block;
            background-color: var(--background-light);
            color: var(--primary-color);
            padding: 0.25rem 0.75rem;
            border-radius: 1rem;
            font-size: 0.8rem;
            margin-right: 0.5rem;
            margin-bottom: 0.5rem;
        }

        .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) * 6) 0;
            position: relative;
            z-index: 1;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(rgba(52, 58, 64, 0.7), rgba(52, 58, 64, 0.9));
            z-index: -1;
        }

        .hero-title {
            font-size: 3.5rem;
            font-weight: 900;
            margin-bottom: var(--spacing-unit);
            line-height: 1.2;
        }

        .hero-subtitle {
            font-size: 1.5rem;
            font-weight: 400;
            color: rgba(255, 255, 255, 0.9);
            margin-bottom: calc(var(--spacing-unit) * 2.5);
        }

        .main-nav {
            background-color: rgba(52, 58, 64, 0.95);
            height: var(--header-height);
            display: flex;
            align-items: center;
            position: sticky;
            top: 0;
            z-index: 100;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
        }

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

        .site-logo {
            font-size: 2rem;
            font-weight: 900;
            color: #ffffff;
            letter-spacing: -1px;
        }
        
        .site-logo:hover {
            color: var(--primary-color);
        }

        .main-nav ul {
            list-style: none;
            display: flex;
            margin-left: auto;
        }

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

        .main-nav a {
            color: rgba(255, 255, 255, 0.8);
            font-weight: 600;
            font-size: 1.1rem;
            padding: 0.5rem 0;
            position: relative;
            transition: color 0.3s ease;
        }

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

        .footer {
            background-color: var(--background-dark);
            color: rgba(255, 255, 255, 0.7);
            padding: calc(var(--spacing-unit) * 3) 0 calc(var(--spacing-unit) * 2) 0;
            margin-top: auto;
            font-size: 0.9rem;
        }

        .footer .container {
            text-align: center;
        }

        .footer-nav {
            margin-bottom: var(--spacing-unit);
        }

        .footer-nav a {
            color: rgba(255, 255, 255, 0.7);
            margin: 0 var(--spacing-unit);
        }
        
        .footer-nav a:hover {
            color: #ffffff;
        }

        .footer-copyright {
            margin-top: var(--spacing-unit);
            opacity: 0.7;
        }

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

        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: calc(var(--spacing-unit) * 2);
        }
        
        .category-details {
            text-align: center;
            margin-bottom: calc(var(--spacing-unit) * 3);
        }
        
        .category-title {
            font-size: 2.8rem;
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: var(--spacing-unit);
        }
        
        .category-description {
            font-size: 1.1rem;
            color: var(--text-muted);
            max-width: 800px;
            margin: 0 auto;
            line-height: 1.8;
        }

        .faq-section {
            background-color: #ffffff;
            padding: calc(var(--spacing-unit) * 4) 0;
        }

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

        .faq-question {
            background-color: var(--background-light);
            padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
            font-weight: 600;
            cursor: pointer;
            position: relative;
            transition: background-color 0.3s ease;
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-unit) * 1.5;
            font-size: 1.5rem;
            top: 50%;
            transform: translateY(-50%);
            transition: transform 0.3s ease;
        }

        .faq-item.active .faq-question::after {
            content: '-';
            transform: translateY(-50%) rotate(0deg); /* Reset for '-' sign */
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.4s ease-out, padding 0.4s ease-out;
            padding: 0 calc(var(--spacing-unit) * 1.5);
            background-color: var(--card-bg);
        }
        
        .faq-answer p {
            padding: var(--spacing-unit) 0;
            margin: 0;
        }

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

        .cta-section {
            background-color: var(--primary-color);
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 5) 0;
            background-image: url('/assets/images/backpic/back-2.webp');
            background-size: cover;
            background-position: center;
            position: relative;
            z-index: 1;
        }

        .cta-section::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(rgba(255, 107, 107, 0.85), rgba(255, 107, 107, 0.95));
            z-index: -1;
        }

        .cta-title {
            font-size: 2.8rem;
            font-weight: 900;
            margin-bottom: var(--spacing-unit);
        }

        .cta-subtitle {
            font-size: 1.2rem;
            margin-bottom: calc(var(--spacing-unit) * 2);
        }
        
        .cta-btn {
            background-color: var(--background-dark);
            color: #ffffff;
            border: none;
            font-size: 1.2rem;
            padding: 1rem 2.5rem;
            box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
        }
        
        .cta-btn:hover {
            background-color: var(--text-color);
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
        }

        /* Responsive */
        @media (max-width: 992px) {
            .hero-title {
                font-size: 3rem;
            }
            .hero-subtitle {
                font-size: 1.3rem;
            }
            .section-title {
                font-size: 2.2rem;
            }
            .card-image {
                height: 180px;
            }
        }

        @media (max-width: 768px) {
            .main-nav {
                height: auto;
                flex-direction: column;
                padding: var(--spacing-unit) 0;
            }
            .main-nav .container {
                flex-direction: column;
            }
            .site-logo {
                margin-bottom: var(--spacing-unit);
            }
            .main-nav ul {
                flex-direction: column;
                align-items: center;
                width: 100%;
                margin-left: 0;
            }
            .main-nav li {
                margin-left: 0;
                margin-bottom: var(--spacing-unit);
            }
            .hero-title {
                font-size: 2.5rem;
            }
            .hero-subtitle {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 2rem;
            }
            .category-title {
                font-size: 2.4rem;
            }
            .category-description {
                font-size: 1rem;
            }
            .cta-title {
                font-size: 2.4rem;
            }
            .cta-subtitle {
                font-size: 1.1rem;
            }
            .footer-nav {
                display: flex;
                flex-direction: column;
            }
            .footer-nav a {
                margin: 0.5rem 0;
            }
        }

        @media (max-width: 576px) {
            .hero {
                padding: calc(var(--spacing-unit) * 4) 0;
            }
            .hero-title {
                font-size: 2rem;
            }
            .hero-subtitle {
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.8rem;
                margin-bottom: calc(var(--spacing-unit) * 2);
            }
            .card-content {
                padding: var(--spacing-unit);
            }
            .card-title {
                font-size: 1.1rem;
            }
            .card-description {
                font-size: 0.9rem;
            }
            .category-title {
                font-size: 2rem;
            }
            .cta-title {
                font-size: 2rem;
            }
            .btn {
                padding: 0.6rem 1.2rem;
                font-size: 0.9rem;
            }
            .cta-btn {
                padding: 0.8rem 1.8rem;
                font-size: 1rem;
            }
        }

/* roulang page: category2 */
:root {
            --primary-color: #4CAF50;
            --secondary-color: #FFC107;
            --background-color: #f4f7f6;
            --text-color: #333;
            --light-text-color: #666;
            --border-color: #ddd;
            --card-background: #fff;
            --footer-background: #333;
            --footer-text-color: #ccc;
            --header-background: #fff;
            --nav-link-hover-color: #4CAF50;
            --button-primary-bg: #4CAF50;
            --button-primary-text: #fff;
            --button-secondary-bg: #FFC107;
            --button-secondary-text: #333;
            --radius-sm: 4px;
            --radius-md: 8px;
            --radius-lg: 12px;
            --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
            --container-width: 1200px;
            --spacing-xs: 8px;
            --spacing-sm: 12px;
            --spacing-md: 16px;
            --spacing-lg: 24px;
            --spacing-xl: 32px;
        }

        body {
            margin: 0;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            color: var(--text-color);
            background-color: var(--background-color);
            line-height: 1.6;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        .container {
            width: 90%;
            max-width: var(--container-width);
            margin: 0 auto;
            padding: 0 var(--spacing-md);
        }

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

        a:hover {
            color: var(--nav-link-hover-color);
        }

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

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

        .main-nav ul {
            list-style: none;
            padding: 0;
            margin: 0;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .main-nav li {
            margin: 0 var(--spacing-md);
        }

        .main-nav a {
            font-weight: 500;
            color: var(--text-color);
            padding: var(--spacing-sm) var(--spacing-md);
            position: relative;
            transition: color 0.3s ease;
        }

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

        .main-nav a:not(.active):hover {
            color: var(--nav-link-hover-color);
        }

        .hero {
            background-image: url('/assets/images/backpic/back-2.webp');
            background-size: cover;
            background-position: center;
            color: #fff;
            text-align: center;
            padding: var(--spacing-xl) var(--spacing-md);
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 400px;
            border-radius: var(--radius-lg);
            margin: var(--spacing-lg) auto;
            max-width: var(--container-width);
            overflow: hidden;
        }

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

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

        .hero h1 {
            font-size: 2.8em;
            margin-bottom: var(--spacing-sm);
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.3em;
            margin-bottom: var(--spacing-lg);
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .button-primary {
            display: inline-block;
            background-color: var(--button-primary-bg);
            color: var(--button-primary-text);
            padding: var(--spacing-sm) var(--spacing-lg);
            border-radius: var(--radius-md);
            font-weight: bold;
            transition: background-color 0.3s ease, transform 0.2s ease;
            box-shadow: var(--shadow-md);
        }

        .button-primary:hover {
            background-color: #388E3C;
            transform: translateY(-2px);
        }

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

        .section-title {
            text-align: center;
            font-size: 2em;
            margin-bottom: var(--spacing-lg);
            color: var(--primary-color);
        }

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

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

        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 24px rgba(0,0,0,0.15);
        }

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

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

        .card .card-title {
            font-size: 1.3em;
            margin-bottom: var(--spacing-sm);
            color: var(--text-color);
            font-weight: bold;
        }

        .card .card-description {
            font-size: 0.95em;
            color: var(--light-text-color);
            margin-bottom: var(--spacing-md);
            flex-grow: 1;
        }

        .card .card-meta {
            font-size: 0.85em;
            color: var(--light-text-color);
            margin-top: auto;
        }

        .faq-section {
            background-color: #fff;
            padding: var(--spacing-xl) 0;
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-md);
        }

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

        .faq-item:last-child {
            border-bottom: none;
            margin-bottom: 0;
            padding-bottom: 0;
        }

        .faq-question {
            font-size: 1.1em;
            font-weight: bold;
            cursor: pointer;
            position: relative;
            padding-left: var(--spacing-lg);
        }

        .faq-question::before {
            content: '+';
            position: absolute;
            left: 0;
            font-weight: bold;
            font-size: 1.2em;
            color: var(--primary-color);
            transition: transform 0.3s ease;
        }

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

        .faq-answer {
            font-size: 1em;
            color: var(--light-text-color);
            padding-left: var(--spacing-lg);
            margin-top: var(--spacing-sm);
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
        }

        .faq-item.open .faq-answer {
            max-height: 200px; /* Adjust as needed */
        }

        .cta-section {
            background-color: var(--primary-color);
            color: #fff;
            text-align: center;
            padding: var(--spacing-xl) var(--spacing-md);
            border-radius: var(--radius-lg);
            margin: var(--spacing-lg) auto;
            max-width: var(--container-width);
        }

        .cta-section h2 {
            font-size: 2em;
            margin-bottom: var(--spacing-md);
        }

        .cta-section p {
            font-size: 1.1em;
            margin-bottom: var(--spacing-lg);
        }

        .button-secondary {
            display: inline-block;
            background-color: var(--button-secondary-bg);
            color: var(--button-secondary-text);
            padding: var(--spacing-sm) var(--spacing-lg);
            border-radius: var(--radius-md);
            font-weight: bold;
            transition: background-color 0.3s ease, transform 0.2s ease;
            box-shadow: var(--shadow-md);
        }

        .button-secondary:hover {
            background-color: #e0a800;
            transform: translateY(-2px);
        }

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

        .footer-nav {
            margin-bottom: var(--spacing-md);
        }

        .footer-nav a {
            color: var(--footer-text-color);
            margin: 0 var(--spacing-sm);
            transition: color 0.3s ease;
        }

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

        .footer-copyright {
            font-size: 0.9em;
        }

        /* Responsive Styles */
        @media (max-width: 1024px) {
            .hero h1 {
                font-size: 2.4em;
            }
            .hero p {
                font-size: 1.2em;
            }
            .section-title {
                font-size: 1.8em;
            }
        }

        @media (max-width: 768px) {
            .main-nav ul {
                flex-direction: column;
                text-align: center;
                padding-top: var(--spacing-md);
            }
            .main-nav li {
                margin: var(--spacing-sm) 0;
            }
            .hero {
                min-height: 300px;
                padding: var(--spacing-lg) var(--spacing-md);
            }
            .hero h1 {
                font-size: 2em;
            }
            .hero p {
                font-size: 1.1em;
            }
            .card-grid {
                grid-template-columns: 1fr;
            }
            .cta-section h2, .cta-section p {
                font-size: 1.5em;
            }
        }

        @media (max-width: 576px) {
            .hero h1 {
                font-size: 1.8em;
            }
            .hero p {
                font-size: 1em;
            }
            .section-title {
                font-size: 1.6em;
            }
            .footer-nav a {
                display: block;
                margin: var(--spacing-xs) 0;
            }
        }

/* roulang page: category3 */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --accent-color: #ffc107;
            --background-color: #f8f9fa;
            --text-color: #343a40;
            --light-text-color: #6c757d;
            --border-color: #dee2e6;
            --card-background: #ffffff;
            --footer-background: #343a40;
            --footer-text-color: #ffffff;
            --header-background: #ffffff;
            --nav-hover-color: #e9ecef;
            --button-hover-bg: #0056b3;
            --button-hover-text: #ffffff;
            --container-max-width: 1200px;
            --spacing-xs: 0.5rem;
            --spacing-sm: 1rem;
            --spacing-md: 1.5rem;
            --spacing-lg: 2rem;
            --spacing-xl: 3rem;
            --border-radius-sm: 4px;
            --border-radius-md: 8px;
            --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --transition-ease: all 0.3s ease;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background-color: var(--background-color);
            scroll-behavior: smooth;
        }

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

        a:hover {
            color: var(--button-hover-bg);
            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-sm);
        }

        .btn {
            display: inline-block;
            padding: var(--spacing-sm) var(--spacing-md);
            border: none;
            border-radius: var(--border-radius-sm);
            cursor: pointer;
            transition: var(--transition-ease);
            text-align: center;
            font-weight: 500;
        }

        .btn-primary {
            background-color: var(--primary-color);
            color: #ffffff;
        }

        .btn-primary:hover {
            background-color: var(--button-hover-bg);
            color: var(--button-hover-text);
            text-decoration: none;
        }

        .btn-secondary {
            background-color: var(--secondary-color);
            color: #ffffff;
        }

        .btn-secondary:hover {
            background-color: #5a6268;
            color: var(--button-hover-text);
            text-decoration: none;
        }
        
        .section-title {
            text-align: center;
            font-size: 2rem;
            margin-bottom: var(--spacing-lg);
            color: var(--text-color);
            font-weight: 600;
        }

        /* Header & Navigation */
        .main-header {
            background-color: var(--header-background);
            padding: var(--spacing-sm) 0;
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        
        .main-nav {
            display: flex;
            justify-content: center;
            align-items: center;
        }
        
        .main-nav ul {
            list-style: none;
            display: flex;
            gap: var(--spacing-md);
        }
        
        .main-nav a {
            color: var(--text-color);
            font-weight: 500;
            padding: var(--spacing-sm) var(--spacing-md);
            border-radius: var(--border-radius-sm);
            transition: var(--transition-ease);
            font-size: 1.1rem;
            position: relative;
            overflow: hidden; /* For underline effect */
        }
        
        .main-nav a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 0;
            height: 2px;
            background-color: var(--primary-color);
            transition: width 0.3s ease-in-out;
        }
        
        .main-nav a:hover::after,
        .main-nav a.active::after {
            width: 80%;
        }
        
        .main-nav a:hover,
        .main-nav a.active {
            color: var(--primary-color);
            background-color: var(--nav-hover-color);
            text-decoration: none;
        }

        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--primary-color);
            margin-right: var(--spacing-lg);
            text-decoration: none;
        }
        
        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-3.webp');
            background-size: cover;
            background-position: center;
            color: #ffffff;
            text-align: center;
            padding: var(--spacing-xl) var(--spacing-sm);
            min-height: 60vh;
            display: flex;
            justify-content: center;
            align-items: 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);
        }
        
        .hero .container {
            position: relative;
            z-index: 1;
        }

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

        .hero p {
            font-size: 1.3rem;
            margin-bottom: var(--spacing-lg);
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
            color: rgba(255, 255, 255, 0.9);
        }

        .hero .btn-primary {
            font-size: 1.2rem;
            padding: var(--spacing-md) var(--spacing-xl);
        }

        /* Content Section */
        .content-section {
            padding: var(--spacing-xl) 0;
        }

        .content-section h2 {
            text-align: center;
            font-size: 2rem;
            margin-bottom: var(--spacing-lg);
            color: var(--text-color);
            font-weight: 600;
        }

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

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

        .content-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
        }

        .content-card img {
            width: 100%;
            height: 220px; /* Fixed height for consistent card look */
            object-fit: cover;
        }

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

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

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

        .content-card .btn {
            margin-top: auto; /* Pushes button to the bottom */
            align-self: flex-start;
        }

        /* Features Section */
        .features-section {
            padding: var(--spacing-xl) 0;
            background-color: #ffffff;
        }

        .features-section h2 {
             font-size: 2rem;
            margin-bottom: var(--spacing-lg);
            color: var(--text-color);
            font-weight: 600;
            text-align: center;
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: var(--spacing-lg);
        }
        
        @media (max-width: 992px) {
            .features-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        @media (max-width: 768px) {
            .features-grid {
                grid-template-columns: 1fr;
            }
        }

        .feature-item {
            text-align: center;
            padding: var(--spacing-md);
        }
        
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: var(--spacing-sm);
        }

        .feature-item h3 {
            font-size: 1.3rem;
            margin-bottom: var(--spacing-xs);
            color: var(--text-color);
            font-weight: 600;
        }

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

        /* FAQ Section */
        .faq-section {
            padding: var(--spacing-xl) 0;
            background-color: var(--background-color);
        }

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

        .faq-item {
            border-bottom: 1px solid var(--border-color);
        }
        .faq-item:last-child {
            border-bottom: none;
        }

        .faq-question {
            padding: var(--spacing-md);
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-weight: 500;
            background-color: #ffffff;
            transition: background-color 0.3s ease;
        }
        
        .faq-question:hover {
            background-color: var(--nav-hover-color);
        }
        
        .faq-question .icon {
            transition: transform 0.3s ease;
            font-size: 1.2rem;
            color: var(--primary-color);
        }

        .faq-answer {
            padding: 0 var(--spacing-md);
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-in-out, padding 0.3s ease-in-out;
            background-color: var(--card-background);
        }
        .faq-answer p {
            padding-top: var(--spacing-sm);
            padding-bottom: var(--spacing-md);
            font-size: 0.95rem;
            color: var(--light-text-color);
        }

        .faq-item.active .faq-question {
            background-color: var(--nav-hover-color);
            font-weight: bold;
        }
        .faq-item.active .faq-question .icon {
            transform: rotate(90deg);
        }

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


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

        .cta-section h2 {
            font-size: 2.5rem;
            margin-bottom: var(--spacing-md);
        }

        .cta-section p {
            font-size: 1.2rem;
            margin-bottom: var(--spacing-lg);
            opacity: 0.9;
        }

        .cta-section .btn-accent {
            background-color: var(--accent-color);
            color: var(--text-color);
            font-size: 1.2rem;
            padding: var(--spacing-md) var(--spacing-xl);
        }
        .cta-section .btn-accent:hover {
            background-color: #e0a800;
            color: var(--text-color);
        }

        /* Footer */
        .footer {
            background-color: var(--footer-background);
            color: var(--footer-text-color);
            padding: var(--spacing-lg) 0 var(--spacing-sm);
            text-align: center;
            font-size: 0.9rem;
        }

        .footer .container {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--spacing-sm);
        }

        .footer-nav a {
            color: var(--footer-text-color);
            margin: 0 var(--spacing-sm);
            transition: color 0.3s ease;
        }

        .footer-nav a:hover {
            color: var(--accent-color);
            text-decoration: underline;
        }
        
        .footer-copyright {
            opacity: 0.8;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .main-nav ul {
                flex-direction: column;
                align-items: center;
                padding-top: var(--spacing-sm);
            }
            .main-nav li {
                margin-bottom: var(--spacing-sm);
            }
            .main-nav a {
                padding: var(--spacing-sm);
            }
            
            .hero h1 {
                font-size: 2.5rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .content-grid {
                grid-template-columns: 1fr;
            }
            .features-grid {
                grid-template-columns: 1fr;
            }
            .cta-section h2 {
                font-size: 2rem;
            }
            .cta-section p {
                font-size: 1.1rem;
            }
        }
        
        @media (max-width: 520px) {
            .logo {
                font-size: 1.5rem;
                margin-right: 0;
            }
            .main-nav a {
                font-size: 1rem;
            }
            .hero h1 {
                font-size: 2rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.6rem;
            }
            .content-card-body {
                padding: var(--spacing-sm);
            }
            .content-card h3 {
                font-size: 1.2rem;
            }
            .footer-nav {
                display: flex;
                flex-direction: column;
                gap: var(--spacing-xs);
            }
            .footer-nav a {
                margin: 0;
            }
        }

/* roulang page: category4 */
:root {
        --primary-color: #007bff;
        --secondary-color: #6c757d;
        --accent-color: #ffc107;
        --background-color: #f8f9fa;
        --text-color: #343a40;
        --light-text-color: #6c757d;
        --border-color: #dee2e6;
        --card-background: #ffffff;
        --footer-background: #343a40;
        --footer-text-color: #ffffff;
        --hover-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
        --card-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
        --border-radius: 8px;
        --spacing-unit: 1rem;
        --container-max-width: 1200px;
    }

    body {
        margin: 0;
        font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        line-height: 1.6;
        color: var(--text-color);
        background-color: var(--background-color);
        scroll-behavior: smooth;
    }

    .container {
        width: 90%;
        max-width: var(--container-max-width);
        margin: 0 auto;
        padding: var(--spacing-unit) 0;
    }

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

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

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

    .btn {
        display: inline-block;
        padding: 0.75rem 1.5rem;
        background-color: var(--primary-color);
        color: #ffffff;
        border: none;
        border-radius: var(--border-radius);
        font-size: 1rem;
        cursor: pointer;
        transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
        text-align: center;
    }

    .btn:hover,
    .btn:focus {
        background-color: #0056b3;
        color: #ffffff;
        text-decoration: none;
        transform: translateY(-2px);
        box-shadow: var(--hover-shadow);
    }

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

    .btn-accent:hover,
    .btn-accent:focus {
        background-color: #e0a800;
        color: var(--text-color);
    }

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

    .section h2 {
        text-align: center;
        font-size: 2.5rem;
        margin-bottom: calc(var(--spacing-unit) * 2);
        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-3.webp');
        background-size: cover;
        background-position: center;
        color: #ffffff;
        text-align: center;
        padding: calc(var(--spacing-unit) * 6) 0;
        position: relative;
    }

    .hero::before {
        content: '';
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: linear-gradient(to bottom, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.3));
        z-index: 1;
    }

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

    .hero h1 {
        font-size: 3.5rem;
        margin-bottom: var(--spacing-unit);
        line-height: 1.2;
    }

    .hero p {
        font-size: 1.3rem;
        margin-bottom: calc(var(--spacing-unit) * 3);
        max-width: 800px;
        margin-left: auto;
        margin-right: auto;
    }

    .card-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
        gap: calc(var(--spacing-unit) * 2);
    }

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

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

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

    .card-content {
        padding: calc(var(--spacing-unit) * 1.5);
        flex-grow: 1;
        display: flex;
        flex-direction: column;
    }

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

    .card-content p {
        font-size: 1rem;
        margin-bottom: calc(var(--spacing-unit) * 1.5);
        flex-grow: 1;
    }

    .card-content .btn {
        margin-top: auto;
    }

    .faq-section {
        background-color: #ffffff;
        padding: calc(var(--spacing-unit) * 3) 0;
    }

    .faq-item {
        border-bottom: 1px solid var(--border-color);
        padding: var(--spacing-unit) 0;
    }

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

    .faq-question {
        font-size: 1.2rem;
        font-weight: bold;
        color: var(--primary-color);
        cursor: pointer;
        padding-right: 20px;
        position: relative;
    }

    .faq-question::after {
        content: '+';
        position: absolute;
        right: 0;
        font-size: 1.5rem;
        transition: transform 0.3s ease;
    }

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

    .faq-answer {
        font-size: 1rem;
        color: var(--light-text-color);
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease-out;
        padding-top: 0;
    }

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

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

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

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

    .cta-section .btn {
        background-color: var(--accent-color);
        color: var(--text-color);
        font-weight: bold;
        font-size: 1.1rem;
    }

    .cta-section .btn:hover,
    .cta-section .btn:focus {
        background-color: #e0a800;
    }

    .footer {
        background-color: var(--footer-background);
        color: var(--footer-text-color);
        padding: calc(var(--spacing-unit) * 3) 0;
        text-align: center;
    }

    .footer-nav {
        margin-bottom: var(--spacing-unit);
    }

    .footer-nav a {
        color: var(--footer-text-color);
        margin: 0 var(--spacing-unit);
        transition: color 0.3s ease;
    }

    .footer-nav a:hover,
    .footer-nav a:focus {
        color: var(--accent-color);
        text-decoration: underline;
    }

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

    /* Navigation Styles */
    .main-nav-container {
        background-color: var(--card-background);
        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    }

    .main-nav {
        padding: 0;
        display: flex;
        justify-content: center;
        align-items: center;
        height: 80px;
    }

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

    .main-nav li {
        margin: 0 var(--spacing-unit);
    }

    .main-nav a {
        font-size: 1.1rem;
        font-weight: 500;
        color: var(--text-color);
        padding: 0.5rem 1rem;
        transition: color 0.3s ease, background-color 0.3s ease, border-radius 0.3s ease;
        border-radius: var(--border-radius);
    }

    .main-nav a:hover,
    .main-nav a:focus {
        color: var(--primary-color);
        background-color: rgba(0, 123, 255, 0.1);
        text-decoration: none;
    }

    .main-nav a.active {
        color: var(--primary-color);
        font-weight: bold;
        background-color: rgba(0, 123, 255, 0.1);
    }

    .site-logo {
        font-size: 1.8rem;
        font-weight: bold;
        color: var(--primary-color);
        margin-right: calc(var(--spacing-unit) * 3);
    }

    /* Responsive Adjustments */
    @media (max-width: 1024px) {
        .main-nav ul {
            flex-direction: column;
            position: absolute;
            top: 80px;
            left: 0;
            width: 100%;
            background-color: var(--card-background);
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
            display: none; /* Hidden by default, controlled by JS */
            padding: var(--spacing-unit) 0;
        }

        .main-nav ul.show {
            display: flex;
        }

        .main-nav li {
            margin: var(--spacing-unit) 0;
            text-align: center;
        }

        .main-nav a {
            padding: 1rem;
            width: 100%;
        }

        .menu-toggle {
            display: block;
            font-size: 2rem;
            cursor: pointer;
            position: absolute;
            right: var(--spacing-unit);
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-color);
        }

        .main-nav-container {
            position: relative;
            padding-right: 50px; /* Space for toggle button */
        }
        
        .site-logo {
            margin-right: auto;
            margin-left: var(--spacing-unit);
        }

        .hero h1 {
            font-size: 2.8rem;
        }

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

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

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

        .cta-section h2 {
            font-size: 2.2rem;
        }
    }

    @media (max-width: 768px) {
        .hero {
            padding: calc(var(--spacing-unit) * 4) 0;
        }
        .hero h1 {
            font-size: 2.5rem;
        }
        .hero p {
            font-size: 1rem;
        }
        .section {
            padding: calc(var(--spacing-unit) * 2) 0;
        }
        .section h2 {
            font-size: 1.8rem;
            margin-bottom: var(--spacing-unit);
        }
        .cta-section {
            padding: calc(var(--spacing-unit) * 3) 0;
        }
        .cta-section h2 {
            font-size: 2rem;
        }
        .cta-section p {
            font-size: 1.1rem;
            margin-bottom: calc(var(--spacing-unit) * 2);
        }
    }