/* roulang page: index */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --background-color: #f8f9fa;
            --text-color: #333;
            --light-text-color: #666;
            --border-color: #dee2e6;
            --card-background: #fff;
            --button-hover-bg: #0056b3;
            --footer-background: #343a40;
            --footer-text-color: #f8f9fa;
            --font-family: 'Arial', sans-serif;
            --container-max-width: 1200px;
            --spacing-unit: 1rem;
            --borderRadius: 0.375rem;
            --shadow: 0 4px 12px rgba(0,0,0,0.08);
        }

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

        body {
            font-family: var(--font-family);
            color: var(--text-color);
            background-color: var(--background-color);
            line-height: 1.7;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

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

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

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

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

        button, input, select, textarea {
            font-family: inherit;
            font-size: inherit;
        }

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

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

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

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

        .nav-links li {
            margin-left: calc(var(--spacing-unit) * 1.5);
        }

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

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

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

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

        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            color: #fff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 6) calc(var(--spacing-unit) * 2);
            position: relative;
        }

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

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

        .hero h1 {
            font-size: 3rem;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: calc(var(--spacing-unit) * 3);
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        .cta-button {
            display: inline-block;
            background-color: var(--primary-color);
            color: #fff;
            padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2.5);
            font-size: 1.1rem;
            font-weight: bold;
            border-radius: var(--borderRadius);
            transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
            border: none;
            cursor: pointer;
        }

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

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

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

        .section-title::after {
            content: '';
            position: absolute;
            bottom: -15px;
            left: 50%;
            transform: translateX(-50%);
            width: 60px;
            height: 4px;
            background-color: var(--primary-color);
            border-radius: 2px;
        }

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

        .card {
            background-color: var(--card-background);
            border-radius: var(--borderRadius);
            box-shadow: var(--shadow);
            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: 0 16px 24px rgba(0,0,0,0.12);
        }

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

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

        .card-title {
            font-size: 1.4rem;
            margin-bottom: var(--spacing-unit);
            color: var(--text-color);
        }

        .card-text {
            color: var(--light-text-color);
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            flex-grow: 1;
        }

        .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;
        }

        .card-link {
            display: inline-block;
            margin-top: auto;
            color: var(--primary-color);
            font-weight: bold;
        }

        /* Features Section */
        .features-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: calc(var(--spacing-unit) * 3);
            text-align: center;
        }

        .feature-item {
            background-color: var(--card-background);
            padding: calc(var(--spacing-unit) * 2);
            border-radius: var(--borderRadius);
            box-shadow: var(--shadow);
        }

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

        .feature-title {
            font-size: 1.2rem;
            font-weight: bold;
            margin-bottom: calc(var(--spacing-unit) * 0.5);
        }

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

        /* FAQ Section */
        .faq-list {
            list-style: none;
            max-width: 800px;
            margin: 0 auto;
        }

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

        .faq-question {
            padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
            font-weight: bold;
            cursor: pointer;
            position: relative;
            background-color: var(--card-background);
            border: none;
            width: 100%;
            text-align: left;
            font-size: 1.1rem;
            color: var(--text-color);
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: calc(var(--spacing-unit) * 1.5);
            font-size: 1.2rem;
            transition: transform 0.2s ease-in-out;
        }

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

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-in-out;
            padding: 0 calc(var(--spacing-unit) * 1.5);
            color: var(--light-text-color);
        }

        .faq-item.open .faq-answer {
            max-height: 200px; /* Adjust as needed */
            padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
            padding-top: calc(var(--spacing-unit) * 0.5);
        }

        /* CTA Section */
        .cta-section {
            background-color: var(--primary-color);
            color: #fff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 5) calc(var(--spacing-unit) * 2);
        }

        .cta-section h2 {
            font-size: 2.2rem;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
        }

        .cta-section p {
            font-size: 1.1rem;
            margin-bottom: calc(var(--spacing-unit) * 3);
            max-width: 700px;
            margin-left: auto;
            margin-right: auto;
        }

        .cta-section .cta-button {
            background-color: #fff;
            color: var(--primary-color);
        }

        .cta-section .cta-button:hover {
            background-color: var(--border-color);
            color: var(--primary-color);
        }

        /* Footer */
        footer {
            background-color: var(--footer-background);
            color: var(--footer-text-color);
            padding: calc(var(--spacing-unit) * 4) 0;
            margin-top: auto; /* Push footer to bottom */
        }

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

        .footer-logo {
            font-size: 1.8rem;
            font-weight: bold;
            color: #fff;
            margin-bottom: var(--spacing-unit);
            display: block;
        }

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

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

        .footer-links a {
            color: var(--footer-text-color);
            font-weight: 500;
        }

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

        .copyright {
            font-size: 0.9rem;
            color: var(--footer-text-color);
            opacity: 0.7;
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .nav-links {
                display: none; /* Hide desktop nav on small screens */
            }

            .mobile-nav-toggle {
                display: block; /* Show mobile toggle */
            }

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

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

            .features-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 768px) {
            .container {
                width: 95%;
            }

            .hero {
                padding: calc(var(--spacing-unit) * 4) calc(var(--spacing-unit) * 1.5);
            }

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

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

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

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

            .cta-section {
                padding: calc(var(--spacing-unit) * 4) calc(var(--spacing-unit) * 1.5);
            }

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

            footer {
                padding: calc(var(--spacing-unit) * 3) 0;
            }
        }
        
        @media (max-width: 576px) {
            .logo {
                font-size: 1.5rem;
            }
            .mobile-nav-toggle {
                font-size: 1.5rem;
            }
            .hero h1 {
                font-size: 2rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .cta-button {
                padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 2);
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .footer-links {
                flex-direction: column;
            }
            .footer-links li {
                margin: calc(var(--spacing-unit) * 0.5) 0;
            }
        }

/* roulang page: article */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --light-color: #f8f9fa;
            --dark-color: #343a40;
            --text-color: #212529;
            --muted-text-color: #495057;
            --border-color: #dee2e6;
            --background-color: #ffffff;
            --card-background: #ffffff;
            --shadow-sm: 0 1px 3px rgba(0,0,0,.12), 0 1px 2px rgba(0,0,0,.24);
            --shadow-md: 0 4px 6px rgba(0,0,0,.1), 0 1px 3px rgba(0,0,0,.08);
            --border-radius-sm: 0.25rem;
            --border-radius-md: 0.375rem;
            --border-radius-lg: 0.5rem;
            --spacing-1: 0.25rem;
            --spacing-2: 0.5rem;
            --spacing-3: 1rem;
            --spacing-4: 1.5rem;
            --spacing-5: 2rem;
            --container-max-width: 1200px;
            --font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
        }

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

        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-3);
        }

        /* 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;
            border-bottom: 1px solid var(--border-color);
        }

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

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

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

        .nav-links li {
            margin-left: var(--spacing-4);
        }

        .nav-links a {
            color: var(--muted-text-color);
            font-weight: 500;
            padding: var(--spacing-1) var(--spacing-2);
            transition: color 0.3s ease, background-color 0.3s ease;
            border-radius: var(--border-radius-sm);
        }

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

        .nav-links a:not(.active):hover {
            color: var(--primary-color);
            background-color: var(--light-color);
            text-decoration: none;
        }

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

        /* Hero Section */
        .hero {
            background-color: var(--light-color);
            background-image: url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            color: white;
            text-align: center;
            padding: var(--spacing-5) 0;
            position: relative;
        }
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.5); /* Dark overlay */
            z-index: 1;
        }
        .hero .container {
            position: relative;
            z-index: 2;
        }

        .hero h1 {
            font-size: 2.8rem;
            margin-bottom: var(--spacing-3);
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: var(--spacing-4);
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

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

        .section-title {
            font-size: 2.2rem;
            text-align: center;
            margin-bottom: var(--spacing-4);
            color: var(--dark-color);
        }

        .article-title {
            font-size: 2.5rem;
            margin-bottom: var(--spacing-3);
            text-align: center;
            line-height: 1.2;
        }

        .article-meta {
            text-align: center;
            color: var(--muted-text-color);
            font-size: 0.95rem;
            margin-bottom: var(--spacing-4);
        }

        .article-meta span {
            margin: 0 var(--spacing-2);
        }

        .article-content {
            font-size: 1.1rem;
            color: var(--text-color);
            max-width: 800px;
            margin: 0 auto;
        }

        .article-content h2, .article-content h3 {
            margin-top: var(--spacing-4);
            margin-bottom: var(--spacing-3);
            line-height: 1.4;
        }

        .article-content p {
            margin-bottom: var(--spacing-3);
        }

        .article-content img {
            margin: var(--spacing-4) auto;
            border-radius: var(--border-radius-md);
            box-shadow: var(--shadow-md);
        }
        
        .no-content {
            text-align: center;
            padding: var(--spacing-5) 0;
        }
        .no-content h2 {
            font-size: 2rem;
            margin-bottom: var(--spacing-3);
            color: var(--secondary-color);
        }
        .no-content p {
            font-size: 1.1rem;
            margin-bottom: var(--spacing-4);
        }
        .btn-primary {
            display: inline-block;
            background-color: var(--primary-color);
            color: white;
            padding: var(--spacing-2) var(--spacing-4);
            border-radius: var(--border-radius-md);
            font-weight: bold;
            transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
            border: none;
            cursor: pointer;
            font-size: 1.1rem;
        }

        .btn-primary:hover {
            background-color: #0056b3;
            text-decoration: none;
            transform: translateY(-2px);
            box-shadow: 0 6px 12px rgba(0,0,0,.15);
        }
        
        .btn-primary:active {
            transform: translateY(0);
            box-shadow: inset 0 2px 4px rgba(0,0,0,.2);
        }

        /* FAQ Section */
        .faq-section {
            background-color: var(--light-color);
            padding: var(--spacing-5) 0;
        }

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

        .faq-question {
            font-size: 1.2rem;
            font-weight: bold;
            color: var(--dark-color);
            cursor: pointer;
            padding: var(--spacing-3);
            position: relative;
            transition: color 0.3s ease;
        }
        .faq-question:hover {
            color: var(--primary-color);
        }

        .faq-question::after {
            content: '+';
            position: absolute;
            right: var(--spacing-3);
            font-size: 1.4rem;
            color: var(--secondary-color);
            transition: transform 0.3s ease;
        }

        .faq-item.open .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-3);
            color: var(--muted-text-color);
            font-size: 1rem;
        }
        
        .faq-item.open .faq-answer {
            max-height: 200px; /* Adjust as needed */
            padding: var(--spacing-3);
        }

        /* Footer */
        footer {
            background-color: var(--dark-color);
            color: var(--light-color);
            padding: var(--spacing-4) 0;
            text-align: center;
        }

        .footer-logo {
            font-size: 1.75rem;
            font-weight: bold;
            color: white;
            text-decoration: none;
            margin-bottom: var(--spacing-3);
            display: inline-block;
        }
        .footer-logo:hover {
            color: var(--primary-color);
        }

        .footer-links {
            list-style: none;
            margin: 0 0 var(--spacing-3) 0;
            padding: 0;
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
        }

        .footer-links li {
            margin: 0 var(--spacing-3) var(--spacing-1) var(--spacing-3);
        }

        .footer-links a {
            color: var(--light-color);
            font-weight: 500;
            transition: color 0.3s ease;
        }

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

        .copyright {
            font-size: 0.9rem;
            color: var(--muted-text-color);
            margin: 0;
        }

        /* Responsive */
        @media (max-width: 768px) {
            .nav-links {
                display: none;
                flex-direction: column;
                position: absolute;
                top: 100%;
                left: 0;
                right: 0;
                background-color: var(--card-background);
                box-shadow: var(--shadow-md);
                padding: var(--spacing-3);
            }

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

            .nav-links li {
                margin: var(--spacing-2) 0;
                text-align: center;
            }

            .mobile-nav-toggle {
                display: block;
            }

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

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

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

            .article-title {
                font-size: 2rem;
            }
            
            .footer-links {
                flex-direction: column;
            }
            .footer-links li {
                margin: var(--spacing-1) 0;
            }
        }
        
        @media (max-width: 480px) {
            .hero h1 {
                font-size: 1.8rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .article-title {
                font-size: 1.8rem;
            }
        }

/* roulang page: category1 */
:root {
            --primary-color: #ff6b6b; /* 珊瑚红 */
            --secondary-color: #4ecdc4; /* 薄荷绿 */
            --background-color: #f8f9fa; /* 浅灰背景 */
            --text-color: #343a40; /* 深灰文字 */
            --subtle-text-color: #6c757d; /* 浅灰文字 */
            --border-color: #dee2e6; /* 浅灰边框 */
            --card-background: #ffffff; /* 白色卡片背景 */
            --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
            --card-radius: 8px;
            --container-max-width: 1200px;
            --spacing-small: 8px;
            --spacing-medium: 16px;
            --spacing-large: 24px;
            --spacing-xlarge: 32px;
            --font-family-base: 'Arial', sans-serif;
            --font-size-base: 16px;
            --line-height-base: 1.6;
            --transition-speed: 0.3s;
        }

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

        body {
            font-family: var(--font-family-base);
            font-size: var(--font-size-base);
            line-height: var(--line-height-base);
            color: var(--text-color);
            background-color: var(--background-color);
            scroll-behavior: smooth;
        }

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

        a:hover,
        a:focus {
            color: #e05a5a; /* 深化主色 */
            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-medium);
        }

        /* Header & Navigation */
        header {
            background-color: var(--card-background);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
            padding: var(--spacing-medium) 0;
            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);
            letter-spacing: 1px;
        }
        .logo:hover {
            text-decoration: none;
        }

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

        .nav-links li a {
            color: var(--text-color);
            font-weight: 500;
            padding: var(--spacing-small) var(--spacing-medium);
            border-radius: var(--card-radius);
            transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
            position: relative;
        }

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

        .mobile-nav-toggle {
            display: none;
            background: none;
            border: none;
            font-size: 2em;
            cursor: pointer;
            color: var(--text-color);
        }

        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            color: white;
            text-align: center;
            padding: var(--spacing-xlarge) 0;
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 50vh;
            position: relative;
        }

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

        .hero .hero-content {
            position: relative;
            z-index: 2;
            max-width: 800px;
            padding: var(--spacing-medium);
        }

        .hero h1 {
            font-size: 2.8em;
            margin-bottom: var(--spacing-medium);
            line-height: 1.3;
        }

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

        .cta-button {
            display: inline-block;
            background-color: var(--secondary-color);
            color: white;
            padding: var(--spacing-medium) var(--spacing-xlarge);
            border-radius: var(--card-radius);
            font-size: 1.1em;
            font-weight: bold;
            transition: background-color var(--transition-speed) ease, transform var(--transition-speed) ease;
        }

        .cta-button:hover,
        .cta-button:focus {
            background-color: #3abfa8; /* 深化辅色 */
            transform: translateY(-3px);
            text-decoration: none;
        }

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

        .section-title {
            text-align: center;
            font-size: 2em;
            margin-bottom: var(--spacing-large);
            font-weight: bold;
        }

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

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

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

        .content-card-image {
            position: relative;
            overflow: hidden;
        }

        .content-card-image img {
            width: 100%;
            aspect-ratio: 16/9;
            object-fit: cover;
        }

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

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

        .content-card-excerpt {
            color: var(--subtle-text-color);
            margin-bottom: var(--spacing-medium);
            flex-grow: 1;
        }

        .content-card-footer {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-top: auto;
        }

        .content-card-meta {
            font-size: 0.9em;
            color: var(--subtle-text-color);
        }

        .content-card-link {
            display: inline-block;
            color: var(--primary-color);
            font-weight: bold;
        }

        .content-card-link:hover {
            text-decoration: none;
        }

        /* FAQ Section */
        .faq-section {
            background-color: #e9ecef; /* 略深的背景 */
            padding: var(--spacing-xlarge) 0;
        }

        .faq-item {
            margin-bottom: var(--spacing-medium);
            background-color: var(--card-background);
            border-radius: var(--card-radius);
            box-shadow: var(--shadow);
        }

        .faq-question {
            background-color: var(--card-background);
            padding: var(--spacing-medium);
            cursor: pointer;
            font-weight: bold;
            position: relative;
            transition: background-color var(--transition-speed) ease;
        }

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

        .faq-item.open .faq-question {
            background-color: #f0f0f0;
        }

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

        .faq-answer {
            padding: var(--spacing-medium);
            background-color: var(--card-background);
            max-height: 0;
            overflow: hidden;
            transition: max-height var(--transition-speed) ease-out, padding var(--transition-speed) ease-out;
            border-top: 1px solid var(--border-color);
        }

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

        /* CTA Section */
        .cta-section {
            background-color: var(--primary-color);
            color: white;
            text-align: center;
            padding: var(--spacing-xlarge) 0;
        }

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

        .cta-section p {
            font-size: 1.1em;
            margin-bottom: var(--spacing-large);
            opacity: 0.9;
        }

        .cta-button.secondary {
            background-color: var(--card-background);
            color: var(--primary-color);
        }

        .cta-button.secondary:hover,
        .cta-button.secondary:focus {
            background-color: #e0e0e0;
        }

        /* Footer */
        footer {
            background-color: var(--text-color);
            color: white;
            padding: var(--spacing-xlarge) 0;
            font-size: 0.9em;
        }

        footer .container {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
        }

        .footer-logo {
            font-size: 1.8em;
            font-weight: bold;
            color: var(--primary-color);
            margin-bottom: var(--spacing-medium);
            letter-spacing: 1px;
        }
        .footer-logo:hover {
            text-decoration: none;
        }

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

        .footer-links li a {
            color: white;
            opacity: 0.8;
            transition: opacity var(--transition-speed) ease;
        }

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

        .copyright {
            opacity: 0.7;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .nav-links {
                display: none; /* Hidden by default on mobile */
                flex-direction: column;
                position: absolute;
                top: 100%;
                left: 0;
                right: 0;
                background-color: var(--card-background);
                padding: var(--spacing-medium);
                box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
            }

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

            .nav-links li {
                width: 100%;
                text-align: center;
            }

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

            .mobile-nav-toggle {
                display: block;
            }

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

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

            .section-title {
                font-size: 1.8em;
            }

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

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

        @media (max-width: 520px) {
            .logo, .footer-logo {
                font-size: 1.5em;
            }

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

/* roulang page: category2 */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --accent-color: #28a745;
            --background-color: #f8f9fa;
            --text-color: #343a40;
            --light-text-color: #6c757d;
            --border-color: #dee2e6;
            --card-background: #ffffff;
            --shadow-color: rgba(0, 0, 0, 0.1);
            --border-radius: 8px;
            --spacing-unit: 16px;
            --container-max-width: 1200px;
        }

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

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

        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);
        }

        /* Header & Navigation */
        header {
            background-color: var(--card-background);
            box-shadow: 0 2px 4px var(--shadow-color);
            padding: var(--spacing-unit) 0;
            position: sticky;
            top: 0;
            z-index: 1000;
        }

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

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

        .logo:hover {
            color: var(--primary-color);
        }

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

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

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

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

        .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 {
            width: 100%;
        }

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

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

        /* Hero Section */
        .hero {
            background-image: url('/assets/images/backpic/back-2.webp');
            background-size: cover;
            background-position: center;
            color: #ffffff;
            text-align: center;
            padding: calc(var(--spacing-unit) * 8) 0;
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 50vh;
        }

        .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: 3.5rem;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            line-height: 1.2;
        }

        .hero p {
            font-size: 1.3rem;
            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: #ffffff;
            padding: calc(var(--spacing-unit) * 1.5) calc(var(--spacing-unit) * 3);
            font-size: 1.2rem;
            font-weight: bold;
            border-radius: var(--border-radius);
            transition: background-color 0.3s ease, transform 0.3s ease;
            box-shadow: 0 4px 8px rgba(40, 167, 69, 0.3);
        }

        .cta-button:hover {
            background-color: #218838;
            transform: translateY(-2px);
            box-shadow: 0 6px 12px rgba(40, 167, 69, 0.4);
        }

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

        .section h2 {
            text-align: center;
            font-size: 2.8rem;
            margin-bottom: calc(var(--spacing-unit) * 4);
            font-weight: 700;
        }

        /* Content Grid */
        .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-background);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: 0 4px 12px var(--shadow-color);
            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 var(--shadow-color);
        }

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

        .content-card-body {
            padding: calc(var(--spacing-unit) * 2);
            flex-grow: 1; /* Allows content to fill available space */
            display: flex;
            flex-direction: column;
            justify-content: space-between; /* Pushes button to bottom */
        }

        .content-card h3 {
            font-size: 1.6rem;
            margin-bottom: var(--spacing-unit);
            color: var(--text-color);
        }

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

        .content-card .card-link {
            display: inline-block;
            margin-top: auto; /* Pushes button to bottom */
            font-weight: bold;
        }

        .content-card .card-link::after {
             content: ' →';
        }

        /* FAQ Section */
        .faq-section {
            background-color: var(--card-background);
            border-radius: var(--border-radius);
            padding: calc(var(--spacing-unit) * 3);
            box-shadow: 0 4px 12px var(--shadow-color);
        }

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

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

        .faq-question {
            font-size: 1.3rem;
            font-weight: 600;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: var(--text-color);
            padding: var(--spacing-unit) 0;
        }

        .faq-question::after {
            content: '+';
            font-size: 1.5rem;
            color: var(--primary-color);
            transition: transform 0.3s ease;
        }

        .faq-item.open .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: 0 var(--spacing-unit); /* Padding for answer text */
            box-sizing: border-box;
        }

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

        /* Footer */
        footer {
            background-color: var(--text-color);
            color: rgba(255, 255, 255, 0.7);
            padding: calc(var(--spacing-unit) * 4) 0;
            margin-top: calc(var(--spacing-unit) * 6);
            text-align: center;
        }

        .footer-logo {
            font-size: 2rem;
            font-weight: bold;
            color: #ffffff;
            margin-bottom: calc(var(--spacing-unit) * 2);
            display: block;
        }

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

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

        .footer-links a {
            color: rgba(255, 255, 255, 0.7);
            transition: color 0.3s ease;
        }

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

        .copyright {
            font-size: 0.9rem;
        }

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

            .mobile-nav-toggle {
                display: block; /* Show toggle button */
            }

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

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

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

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

        @media (max-width: 768px) {
            .hero {
                padding: calc(var(--spacing-unit) * 6) 0;
            }

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

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

            .footer-links {
                flex-direction: column;
                align-items: center;
            }

            .footer-links li {
                margin: calc(var(--spacing-unit) * 0.75) 0;
            }
        }

        @media (max-width: 576px) {
            .logo {
                font-size: 1.6rem;
            }

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

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

            .cta-button {
                font-size: 1rem;
                padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2.5);
            }

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

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

            .content-card h3 {
                font-size: 1.3rem;
            }

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

            .faq-answer {
                font-size: 0.9rem;
            }
        }

/* roulang page: category3 */
:root {
            --primary-color: #ff6b6b;
            --secondary-color: #4ecdc4;
            --accent-color: #f7fff7;
            --background-color: #f8f9fa;
            --text-color: #333;
            --weak-text-color: #777;
            --border-color: #e0e0e0;
            --card-background: #fff;
            --hover-shadow: 0 4px 15px rgba(0,0,0,0.1);
            --border-radius: 8px;
            --container-max-width: 1200px;
            --spacing-unit: 1rem;
        }

        body {
            font-family: 'Arial', sans-serif;
            margin: 0;
            padding: 0;
            background-color: var(--background-color);
            color: var(--text-color);
            line-height: 1.6;
            box-sizing: border-box;
        }

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

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

        header {
            background-color: var(--card-background);
            box-shadow: 0 2px 5px rgba(0,0,0,0.05);
            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: 1.8em;
            font-weight: bold;
            color: var(--primary-color);
            text-decoration: none;
            letter-spacing: -1px;
        }

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

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

        .nav-links a {
            text-decoration: none;
            color: var(--text-color);
            font-weight: 500;
            transition: color 0.3s ease;
            padding: 0.5rem 0;
            position: relative;
        }

        .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);
        }

        .mobile-nav-toggle {
            display: none;
            background: none;
            border: none;
            font-size: 1.8em;
            cursor: pointer;
        }

        .hero {
            background-image: url('/assets/images/backpic/back-3.webp');
            background-size: cover;
            background-position: center;
            color: var(--accent-color);
            text-align: center;
            padding: calc(var(--spacing-unit) * 6) 0;
            position: relative;
            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 .container {
            position: relative;
            z-index: 2;
        }

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

        .hero p {
            font-size: 1.3em;
            max-width: 800px;
            margin: 0 auto;
            color: var(--accent-color);
        }

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

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

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

        .card {
            background-color: var(--card-background);
            border-radius: var(--border-radius);
            box-shadow: 0 2px 10px rgba(0,0,0,0.08);
            overflow: hidden;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            display: flex;
            flex-direction: column;
        }

        .card:hover {
            transform: translateY(-10px);
            box-shadow: var(--hover-shadow);
        }

        .card img {
            width: 100%;
            height: 200px;
            object-fit: cover;
            display: block;
            border-top-left-radius: var(--border-radius);
            border-top-right-radius: var(--border-radius);
        }

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

        .card-title {
            font-size: 1.4em;
            margin-bottom: var(--spacing-unit) * 0.8;
            color: var(--primary-color);
            font-weight: bold;
        }

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

        .card-footer {
            margin-top: auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding-top: var(--spacing-unit);
            border-top: 1px solid var(--border-color);
        }

        .tag {
            background-color: var(--secondary-color);
            color: var(--accent-color);
            padding: 0.3rem 0.7rem;
            border-radius: 50px;
            font-size: 0.8em;
            font-weight: bold;
            display: inline-block;
        }

        .card-button {
            background-color: var(--primary-color);
            color: var(--accent-color);
            border: none;
            padding: 0.7rem 1.5rem;
            border-radius: var(--border-radius);
            font-weight: bold;
            text-decoration: none;
            transition: background-color 0.3s ease, transform 0.2s ease;
            cursor: pointer;
        }

        .card-button:hover {
            background-color: #e05c5c;
            transform: translateY(-2px);
        }

        .feature-section {
            background-color: var(--card-background);
            padding: calc(var(--spacing-unit) * 4) 0;
            text-align: center;
        }

        .feature-section .container {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: calc(var(--spacing-unit) * 3);
        }

        .feature-item {
            display: flex;
            flex-direction: column;
            align-items: center;
        }

        .feature-icon {
            font-size: 3em;
            color: var(--secondary-color);
            margin-bottom: var(--spacing-unit);
        }

        .feature-title {
            font-size: 1.3em;
            font-weight: bold;
            margin-bottom: var(--spacing-unit) * 0.5;
        }

        .feature-description {
            color: var(--weak-text-color);
        }

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

        .faq-item {
            margin-bottom: var(--spacing-unit) * 1.5;
            border-bottom: 1px solid var(--border-color);
            padding-bottom: var(--spacing-unit) * 1.5;
        }

        .faq-question {
            font-size: 1.2em;
            font-weight: bold;
            color: var(--primary-color);
            cursor: pointer;
            position: relative;
            padding-left: 25px;
        }

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

        .faq-question.active::before {
            transform: rotate(180deg);
        }

        .faq-answer {
            font-size: 1em;
            color: var(--weak-text-color);
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
            padding-left: 25px;
            margin-top: var(--spacing-unit);
        }

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

        .cta-section h2 {
            font-size: 2.8em;
            margin-bottom: var(--spacing-unit) * 1.5;
        }

        .cta-section p {
            font-size: 1.2em;
            max-width: 700px;
            margin: 0 auto var(--spacing-unit) * 2;
        }

        .cta-button {
            background-color: var(--card-background);
            color: var(--primary-color);
            border: none;
            padding: 1rem 2.5rem;
            border-radius: var(--border-radius);
            font-weight: bold;
            font-size: 1.1em;
            text-decoration: none;
            transition: background-color 0.3s ease, transform 0.2s ease;
            box-shadow: 0 4px 10px rgba(0,0,0,0.1);
        }

        .cta-button:hover {
            background-color: #e0e0e0;
            transform: translateY(-3px);
        }

        footer {
            background-color: #222;
            color: #ccc;
            padding: calc(var(--spacing-unit) * 3) 0;
            text-align: center;
        }

        .footer-logo {
            font-size: 1.8em;
            font-weight: bold;
            color: var(--accent-color);
            text-decoration: none;
            display: block;
            margin-bottom: var(--spacing-unit);
        }

        .footer-links {
            list-style: none;
            margin: 0;
            padding: 0;
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            margin-bottom: var(--spacing-unit) * 2;
        }

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

        .footer-links a {
            color: #ccc;
            text-decoration: none;
            transition: color 0.3s ease;
        }

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

        .copyright {
            font-size: 0.9em;
            color: #aaa;
            margin: 0;
        }

        @media (max-width: 768px) {
            .nav-links {
                display: none;
                flex-direction: column;
                position: absolute;
                top: 70px; /* Adjust based on header height */
                left: 0;
                width: 100%;
                background-color: var(--card-background);
                box-shadow: 0 2px 5px rgba(0,0,0,0.05);
                padding: var(--spacing-unit) 0;
            }
            .nav-links.active {
                display: flex;
            }
            .nav-links li {
                margin: var(--spacing-unit) 0;
                text-align: center;
            }
            .mobile-nav-toggle {
                display: block;
            }
            .hero h1 {
                font-size: 2.5em;
            }
            .hero p {
                font-size: 1.1em;
            }
            .section-title {
                font-size: 2em;
            }
            .cards-grid {
                grid-template-columns: 1fr;
            }
            .feature-section .container {
                grid-template-columns: 1fr;
            }
            .cta-section h2 {
                font-size: 2em;
            }
            .footer-links {
                flex-direction: column;
            }
            .footer-links li {
                margin: var(--spacing-unit) 0;
            }
        }

/* roulang page: category4 */
:root {
            --primary-color: #007bff;
            --secondary-color: #6c757d;
            --light-gray: #f8f9fa;
            --dark-gray: #343a40;
            --white: #ffffff;
            --black: #000000;
            --border-radius: 8px;
            --shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
            --container-max-width: 1200px;
            --nav-height: 70px;
            --footer-height: 80px;
            --spacing-unit: 1rem;
        }

        /* Basic Reset & Base Styles */
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            font-size: 16px;
            scroll-behavior: smooth;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: var(--dark-gray);
            background-color: var(--light-gray);
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }
        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;
        }
        button {
            cursor: pointer;
            border: none;
            background: none;
            font-family: inherit;
        }
        .container {
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 var(--spacing-unit);
            width: 100%;
        }

        /* Header & Navigation */
        header {
            background-color: var(--white);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            height: var(--nav-height);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        header .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 100%;
        }
        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--black);
            text-decoration: none;
            letter-spacing: -0.5px;
        }
        .logo:hover {
            color: var(--primary-color);
            text-decoration: none;
        }
        .nav-links {
            list-style: none;
            display: flex;
            gap: var(--spacing-unit) * 2;
        }
        .nav-links li a {
            font-size: 1.1rem;
            font-weight: 500;
            color: var(--dark-gray);
            padding: calc(var(--spacing-unit) / 2) var(--spacing-unit);
            border-radius: var(--border-radius);
            transition: background-color 0.3s ease, color 0.3s ease;
        }
        .nav-links li a.active,
        .nav-links li a:hover,
        .nav-links li a:focus {
            background-color: var(--primary-color);
            color: var(--white);
            text-decoration: none;
        }
        .mobile-nav-toggle {
            display: none;
            font-size: 2rem;
            color: var(--dark-gray);
        }

        /* Hero Section */
        .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: var(--white);
            text-align: center;
            padding: var(--spacing-unit) * 6 0;
            display: flex;
            flex-direction: column;
            justify-content: center;
            min-height: 60vh; /* Adjusted for better visual proportion */
            position: relative;
            overflow: hidden;
        }
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.5); /* Overlay for text readability */
            z-index: 1;
        }
        .hero .container {
            position: relative;
            z-index: 2;
        }
        .hero h1 {
            font-size: 3.5rem;
            margin-bottom: var(--spacing-unit);
            font-weight: 700;
            letter-spacing: -1px;
            line-height: 1.2;
        }
        .hero p {
            font-size: 1.5rem;
            margin-bottom: var(--spacing-unit) * 2;
            font-weight: 400;
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }
        .cta-button {
            display: inline-block;
            background-color: var(--primary-color);
            color: var(--white);
            font-size: 1.2rem;
            font-weight: 600;
            padding: var(--spacing-unit) * 1.2 var(--spacing-unit) * 2.5;
            border-radius: var(--border-radius);
            transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
            box-shadow: var(--shadow);
        }
        .cta-button:hover,
        .cta-button:focus {
            background-color: #0056b3;
            color: var(--white);
            text-decoration: none;
            transform: translateY(-2px);
            box-shadow: 0 6px 12px rgba(0,0,0,0.15);
        }

        /* Section Styling */
        .section {
            padding: var(--spacing-unit) * 5 0;
            text-align: center;
        }
        .section h2 {
            font-size: 2.5rem;
            margin-bottom: var(--spacing-unit) * 2;
            font-weight: 700;
            letter-spacing: -0.5px;
        }
        .section p {
            font-size: 1.1rem;
            color: var(--secondary-color);
            max-width: 800px;
            margin: 0 auto var(--spacing-unit) * 3 auto;
        }

        /* Feature Section */
        .features {
            background-color: var(--white);
        }
        .features .container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: var(--spacing-unit) * 3;
        }
        .feature-card {
            background-color: var(--white);
            padding: var(--spacing-unit) * 2;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            text-align: left;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            display: flex;
            flex-direction: column;
        }
        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 16px rgba(0,0,0,0.15);
        }
        .feature-card img {
            margin-bottom: var(--spacing-unit) * 1.5;
            border-radius: var(--border-radius);
            max-height: 200px; /* Fixed height for consistency */
            object-fit: cover;
        }
        .feature-card h3 {
            font-size: 1.5rem;
            margin-bottom: var(--spacing-unit);
            color: var(--dark-gray);
            font-weight: 600;
        }
        .feature-card p {
            font-size: 1rem;
            color: var(--secondary-color);
            flex-grow: 1; /* Allows content to push down footer */
            margin-bottom: var(--spacing-unit) * 2;
        }
        .feature-card .btn-learn-more {
            display: inline-block;
            margin-top: auto; /* Pushes button to the bottom */
            font-weight: 600;
            color: var(--primary-color);
            transition: color 0.3s ease;
        }
        .feature-card .btn-learn-more:hover {
            color: #0056b3;
            text-decoration: underline;
        }

        /* Testimonial Section */
        .testimonials {
            background-color: var(--dark-gray);
            color: var(--white);
        }
        .testimonials h2 {
            color: var(--white);
        }
        .testimonial-carousel {
            display: flex;
            overflow-x: auto; /* Simple horizontal scroll for demo */
            gap: var(--spacing-unit) * 3;
            padding-bottom: var(--spacing-unit) * 2;
            scrollbar-width: thin;
            scrollbar-color: var(--primary-color) var(--dark-gray);
        }
        .testimonial-card {
            background-color: rgba(255, 255, 255, 0.1);
            padding: var(--spacing-unit) * 2;
            border-radius: var(--border-radius);
            text-align: left;
            min-width: 350px; /* Minimum width for cards */
            flex-shrink: 0;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }
        .testimonial-card p {
            font-style: italic;
            color: rgba(255, 255, 255, 0.9);
            margin-bottom: var(--spacing-unit);
            font-size: 1.05rem;
        }
        .testimonial-card .author {
            font-weight: 600;
            color: var(--white);
            margin-top: var(--spacing-unit);
        }
        .testimonial-card .author span {
            font-weight: 400;
            color: rgba(255, 255, 255, 0.8);
            font-size: 0.9rem;
        }

        /* FAQ Section */
        .faq .container {
            text-align: left;
        }
        .faq-item {
            margin-bottom: var(--spacing-unit);
            border: 1px solid #e0e0e0;
            border-radius: var(--border-radius);
            background-color: var(--white);
            overflow: hidden;
            transition: box-shadow 0.3s ease;
        }
        .faq-item:hover {
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        .faq-question {
            background-color: var(--white);
            padding: var(--spacing-unit) * 1.5 var(--spacing-unit) * 2;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-weight: 600;
            font-size: 1.1rem;
            position: relative;
        }
        .faq-question::after {
            content: '+';
            font-size: 1.8rem;
            color: var(--primary-color);
            transition: transform 0.3s ease;
        }
        .faq-item.open .faq-question::after {
            transform: rotate(45deg);
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out, padding 0.3s ease-out;
            background-color: var(--light-gray);
            padding: 0 var(--spacing-unit) * 2;
            font-size: 1rem;
            color: var(--secondary-color);
        }
        .faq-item.open .faq-answer {
            max-height: 200px; /* Adjust as needed */
            padding: var(--spacing-unit) * 1.5 var(--spacing-unit) * 2;
        }

        /* CTA Section */
        .cta {
            background-color: var(--primary-color);
            color: var(--white);
            text-align: center;
            padding: var(--spacing-unit) * 5 0;
        }
        .cta h2 {
            font-size: 2.8rem;
            margin-bottom: var(--spacing-unit);
            color: var(--white);
        }
        .cta p {
            color: rgba(255, 255, 255, 0.9);
            font-size: 1.2rem;
            margin-bottom: var(--spacing-unit) * 3;
        }
        .cta .cta-button {
            background-color: var(--white);
            color: var(--primary-color);
        }
        .cta .cta-button:hover,
        .cta .cta-button:focus {
            background-color: #e9ecef;
            color: #003f7f;
        }

        /* Footer */
        footer {
            background-color: var(--dark-gray);
            color: rgba(255, 255, 255, 0.8);
            padding: var(--spacing-unit) * 4 0 var(--spacing-unit) * 2 0;
            margin-top: auto; /* Pushes footer to the bottom */
            font-size: 0.9rem;
        }
        footer .container {
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .footer-logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--white);
            margin-bottom: var(--spacing-unit) * 2;
            text-decoration: none;
        }
        .footer-logo:hover {
            color: var(--primary-color);
        }
        .footer-links {
            list-style: none;
            display: flex;
            gap: var(--spacing-unit) * 2;
            margin-bottom: var(--spacing-unit) * 2;
            flex-wrap: wrap;
            justify-content: center;
        }
        .footer-links li a {
            color: rgba(255, 255, 255, 0.8);
            transition: color 0.3s ease;
        }
        .footer-links li a:hover,
        .footer-links li a:focus {
            color: var(--white);
            text-decoration: underline;
        }
        .copyright {
            font-size: 0.85rem;
            color: rgba(255, 255, 255, 0.7);
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .nav-links {
                gap: var(--spacing-unit);
            }
            .nav-links li a {
                font-size: 1rem;
            }
            .hero h1 {
                font-size: 3rem;
            }
            .hero p {
                font-size: 1.3rem;
            }
        }
        @media (max-width: 768px) {
            .mobile-nav-toggle {
                display: block;
            }
            .nav-links {
                display: none; /* Hidden by default, toggled by JS */
                flex-direction: column;
                position: absolute;
                top: var(--nav-height);
                left: 0;
                width: 100%;
                background-color: var(--white);
                box-shadow: 0 4px 8px rgba(0,0,0,0.1);
                padding: var(--spacing-unit) 0;
            }
            .nav-links.active {
                display: flex;
            }
            .nav-links li {
                text-align: center;
                width: 100%;
                padding: var(--spacing-unit) 0;
            }
            .nav-links li a {
                display: block;
                width: 100%;
                padding: var(--spacing-unit);
            }
            .nav-links li a.active,
            .nav-links li a:hover,
            .nav-links li a:focus {
                background-color: var(--light-gray);
                color: var(--primary-color);
            }
            .hero h1 {
                font-size: 2.5rem;
            }
            .hero p {
                font-size: 1.1rem;
            }
            .section h2 {
                font-size: 2.2rem;
            }
            .feature-card {
                min-width: 250px; /* Adjust min-width for smaller screens */
            }
            .testimonial-card {
                min-width: 300px;
            }
            .footer-links {
                flex-direction: column;
                gap: var(--spacing-unit);
            }
        }
        @media (max-width: 520px) {
            .hero h1 {
                font-size: 2rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .cta-button {
                font-size: 1rem;
                padding: var(--spacing-unit) * 1 var(--spacing-unit) * 2;
            }
            .section h2 {
                font-size: 2rem;
            }
            .feature-card {
                padding: var(--spacing-unit);
            }
            .feature-card h3 {
                font-size: 1.3rem;
            }
            .testimonial-card {
                min-width: 90%; /* Cards take full width on very small screens */
                margin: 0 auto;
            }
            .testimonial-carousel {
                padding-left: var(--spacing-unit);
                padding-right: var(--spacing-unit);
            }
        }