/* roulang page: index */
:root {
            --primary: #0ea5e9;
            --primary-hover: #0284c7;
            --secondary: #8b5cf6;
            --accent: #06b6d4;
            --bg-dark: #0f172a;
            --bg-card: #1e293b;
            --text-primary: #f1f5f9;
            --text-secondary: #94a3b8;
            --border-color: #334155;
            --radius: 12px;
            --shadow: 0 4px 6px -1px rgba(0,0,0,0.3), 0 2px 4px -2px rgba(0,0,0,0.2);
            --shadow-hover: 0 20px 25px -5px rgba(0,0,0,0.4), 0 8px 10px -6px rgba(0,0,0,0.3);
        }
        * { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            font-family: 'Inter', system-ui, -apple-system, sans-serif;
            background-color: #0f172a;
            color: var(--text-primary);
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
        }
        a { color: inherit; text-decoration: none; }
        img { max-width: 100%; height: auto; display: block; }
        button, input { font: inherit; }
        .container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
        /* Header & Navigation */
        .site-header {
            position: sticky;
            top: 0;
            z-index: 50;
            background-color: rgba(15,23,42,0.85);
            backdrop-filter: blur(16px);
            border-bottom: 1px solid var(--border-color);
        }
        .header-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 72px;
        }
        .logo {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--text-primary);
            letter-spacing: -0.5px;
        }
        .logo span { color: var(--primary); }
        .nav-tabs {
            display: flex;
            align-items: center;
            gap: 8px;
            background: var(--bg-card);
            border-radius: 40px;
            padding: 6px;
        }
        .nav-tabs a {
            padding: 8px 24px;
            border-radius: 40px;
            font-size: 0.95rem;
            font-weight: 500;
            color: var(--text-secondary);
            transition: all 0.2s;
            white-space: nowrap;
        }
        .nav-tabs a.active,
        .nav-tabs a:hover {
            background: var(--primary);
            color: #fff;
            box-shadow: 0 4px 12px rgba(14,165,233,0.35);
        }
        .header-cta {
            background: var(--primary);
            color: #fff;
            padding: 10px 24px;
            border-radius: 40px;
            font-weight: 600;
            font-size: 0.95rem;
            transition: all 0.2s;
        }
        .header-cta:hover {
            background: var(--primary-hover);
            box-shadow: 0 4px 16px rgba(14,165,233,0.45);
            transform: translateY(-1px);
        }
        .mobile-menu-btn { display: none; background: none; border: none; color: #fff; font-size: 1.5rem; cursor: pointer; }
        /* Hero */
        .hero {
            position: relative;
            padding: 120px 0 100px;
            background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
            overflow: hidden;
        }
        .hero-bg {
            position: absolute;
            inset: 0;
            background-image: url('/assets/images/backpic/back-1.png');
            background-size: cover;
            background-position: center;
            opacity: 0.25;
            mix-blend-mode: luminosity;
        }
        .hero-content {
            position: relative;
            z-index: 2;
            max-width: 720px;
            margin: 0 auto;
            text-align: center;
        }
        .hero h1 {
            font-size: 3.2rem;
            font-weight: 800;
            line-height: 1.2;
            margin-bottom: 24px;
            background: linear-gradient(135deg, #fff 0%, #a5f3fc 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .hero p {
            font-size: 1.2rem;
            color: var(--text-secondary);
            margin-bottom: 40px;
        }
        .hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
        .btn {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            padding: 14px 32px;
            border-radius: 40px;
            font-weight: 600;
            font-size: 1rem;
            transition: all 0.2s;
            cursor: pointer;
            border: none;
        }
        .btn-primary {
            background: var(--primary);
            color: #fff;
            box-shadow: 0 4px 14px rgba(14,165,233,0.4);
        }
        .btn-primary:hover { background: var(--primary-hover); transform: translateY(-2px); }
        .btn-outline {
            background: transparent;
            color: #fff;
            border: 1px solid rgba(255,255,255,0.2);
        }
        .btn-outline:hover { background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.4); }
        /* Sections */
        section { padding: 80px 0; }
        .section-header {
            text-align: center;
            margin-bottom: 56px;
        }
        .section-header h2 {
            font-size: 2.2rem;
            font-weight: 700;
            margin-bottom: 16px;
        }
        .section-header p { color: var(--text-secondary); font-size: 1.1rem; }
        /* Feature Cards */
        .features-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        .feature-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius);
            padding: 32px 28px;
            transition: all 0.3s;
            text-align: center;
        }
        .feature-card:hover {
            border-color: var(--primary);
            box-shadow: var(--shadow-hover);
            transform: translateY(-4px);
        }
        .feature-icon {
            width: 56px;
            height: 56px;
            background: rgba(14,165,233,0.15);
            border-radius: 16px;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 20px;
            font-size: 1.5rem;
            color: var(--primary);
        }
        .feature-card h3 { font-size: 1.3rem; margin-bottom: 8px; }
        .feature-card p { color: var(--text-secondary); font-size: 0.95rem; }
        /* Category Entry */
        .category-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 24px;
        }
        .category-card {
            position: relative;
            border-radius: var(--radius);
            overflow: hidden;
            height: 260px;
            background-size: cover;
            background-position: center;
            display: flex;
            align-items: flex-end;
            padding: 24px;
            text-decoration: none;
            color: #fff;
            transition: all 0.3s;
            border: 1px solid var(--border-color);
        }
        .category-card::before {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(transparent 50%, rgba(15,23,42,0.85));
            transition: opacity 0.3s;
        }
        .category-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-hover);
        }
        .category-card-content {
            position: relative;
            z-index: 2;
        }
        .category-card h3 { font-size: 1.6rem; margin-bottom: 4px; }
        .category-card p { font-size: 0.9rem; opacity: 0.8; }
        /* News Cards */
        .news-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        .news-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius);
            overflow: hidden;
            transition: all 0.3s;
        }
        .news-card:hover {
            box-shadow: var(--shadow-hover);
            transform: translateY(-4px);
        }
        .news-card img {
            width: 100%;
            height: 180px;
            object-fit: cover;
            border-bottom: 1px solid var(--border-color);
        }
        .news-card-body { padding: 20px; }
        .news-card-body h3 {
            font-size: 1.1rem;
            margin-bottom: 8px;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }
        .news-card-body p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            margin-bottom: 12px;
            display: -webkit-box;
            -webkit-line-clamp: 3;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }
        .news-meta {
            display: flex;
            justify-content: space-between;
            font-size: 0.8rem;
            color: var(--text-secondary);
        }
        /* Stats */
        .stats-section {
            background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
            border-top: 1px solid var(--border-color);
            border-bottom: 1px solid var(--border-color);
        }
        .stats-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 40px;
            text-align: center;
        }
        .stat-item .num {
            font-size: 2.8rem;
            font-weight: 800;
            color: var(--primary);
            margin-bottom: 8px;
        }
        .stat-item .label { color: var(--text-secondary); }
        /* FAQ */
        .faq-list {
            max-width: 800px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 16px;
        }
        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius);
            padding: 24px 28px;
            transition: all 0.2s;
        }
        .faq-item:hover { border-color: var(--primary); }
        .faq-item h3 { font-size: 1.1rem; margin-bottom: 8px; }
        .faq-item p { color: var(--text-secondary); font-size: 0.95rem; }
        /* CTA */
        .cta-section {
            text-align: center;
            background: linear-gradient(135deg, #0ea5e9, #8b5cf6);
            border-radius: 24px;
            padding: 64px 48px;
            margin: 0 24px;
        }
        .cta-section h2 { font-size: 2rem; font-weight: 700; color: #fff; margin-bottom: 16px; }
        .cta-section p { color: rgba(255,255,255,0.8); margin-bottom: 32px; font-size: 1.1rem; }
        .cta-section .btn { background: #fff; color: #0f172a; }
        .cta-section .btn:hover { background: #e2e8f0; }
        /* Footer */
        .site-footer {
            background: #0b1120;
            border-top: 1px solid var(--border-color);
            padding: 48px 0 32px;
        }
        .footer-inner {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 24px;
        }
        .footer-logo { font-size: 1.3rem; font-weight: 700; }
        .footer-links { display: flex; gap: 24px; }
        .footer-links a { color: var(--text-secondary); transition: color 0.2s; }
        .footer-links a:hover { color: var(--primary); }
        .footer-copy { color: var(--text-secondary); font-size: 0.9rem; }
        @media (max-width: 1024px) {
            .features-grid, .news-grid { grid-template-columns: repeat(2, 1fr); }
            .category-grid { grid-template-columns: 1fr 1fr; }
        }
        @media (max-width: 768px) {
            .hero h1 { font-size: 2.2rem; }
            .hero p { font-size: 1rem; }
            section { padding: 60px 0; }
            .features-grid, .news-grid, .stats-grid { grid-template-columns: 1fr; }
            .category-grid { grid-template-columns: 1fr; }
            .site-header .nav-tabs { display: none; }
            .mobile-menu-btn { display: block; }
            .nav-mobile {
                position: fixed;
                top: 72px;
                left: 0;
                right: 0;
                background: rgba(15,23,42,0.98);
                backdrop-filter: blur(20px);
                border-bottom: 1px solid var(--border-color);
                flex-direction: column;
                padding: 20px;
                gap: 12px;
                display: none;
            }
            .nav-mobile.open { display: flex; }
            .nav-mobile a {
                display: block;
                padding: 12px 20px;
                border-radius: 40px;
                background: var(--bg-card);
                text-align: center;
            }
            .footer-inner { flex-direction: column; text-align: center; }
            .cta-section { margin: 0; border-radius: 0; }
        }
        @media (max-width: 520px) {
            .hero { padding: 80px 0 60px; }
            .hero h1 { font-size: 1.8rem; }
            .btn { padding: 12px 24px; }
        }

/* roulang page: article */
:root {
            --primary: #0ea5e9;
            --primary-hover: #0284c7;
            --secondary: #6366f1;
            --surface-dark: #0f172a;
            --surface-elevated: #1e293b;
            --surface-card: #ffffff;
            --text-on-dark: #f1f5f9;
            --text-muted-dark: #94a3b8;
            --text-on-card: #1e293b;
            --text-secondary-card: #475569;
            --border-subtle: #e2e8f0;
            --border-dark: #334155;
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 20px;
            --shadow-glow: 0 0 20px rgba(14,165,233,0.25);
            --shadow-elevated: 0 20px 40px -12px rgba(0,0,0,0.35);
            --transition-base: 0.25s ease;
        }
        *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
            background: var(--surface-dark);
            color: var(--text-on-dark);
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
        }
        img { max-width: 100%; display: block; }
        a { text-decoration: none; color: inherit; }
        .container {
            width: 100%;
            max-width: 1200px;
            margin-left: auto;
            margin-right: auto;
            padding-left: 1.5rem;
            padding-right: 1.5rem;
        }
        /* 导航 */
        .site-header {
            background: rgba(15,23,42,0.85);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border-bottom: 1px solid var(--border-dark);
            position: sticky;
            top: 0;
            z-index: 50;
        }
        .header-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 64px;
            flex-wrap: wrap;
        }
        .logo {
            font-weight: 700;
            font-size: 1.35rem;
            background: linear-gradient(135deg, #0ea5e9 0%, #6366f1 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            letter-spacing: -0.5px;
        }
        .nav-tabs {
            display: flex;
            gap: 0.5rem;
            background: #1e293b;
            border-radius: 40px;
            padding: 0.25rem;
        }
        .nav-tabs a {
            padding: 0.5rem 1.25rem;
            border-radius: 40px;
            font-size: 0.9rem;
            font-weight: 500;
            color: var(--text-muted-dark);
            transition: all var(--transition-base);
        }
        .nav-tabs a:hover {
            color: var(--text-on-dark);
        }
        .nav-tabs a.active {
            background: var(--primary);
            color: #fff;
            font-weight: 600;
            box-shadow: 0 4px 12px rgba(14,165,233,0.4);
        }
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            color: var(--text-on-dark);
            font-size: 1.6rem;
            cursor: pointer;
        }
        /* 文章 banner */
        .article-banner {
            position: relative;
            background: url('/assets/images/backpic/back-2.png') center/cover no-repeat;
            min-height: 340px;
            display: flex;
            align-items: flex-end;
            padding: 3rem 0 2.5rem;
        }
        .article-banner::before {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(to top, rgba(15,23,42,0.85) 0%, rgba(15,23,42,0.3) 70%);
        }
        .banner-content {
            position: relative;
            z-index: 2;
            width: 100%;
        }
        .badge {
            display: inline-block;
            padding: 0.35rem 1rem;
            background: rgba(14,165,233,0.15);
            border: 1px solid rgba(14,165,233,0.4);
            color: #7dd3fc;
            border-radius: 30px;
            font-size: 0.8rem;
            font-weight: 500;
            margin-bottom: 0.75rem;
        }
        .article-banner h1 {
            font-size: 2.6rem;
            font-weight: 800;
            line-height: 1.2;
            max-width: 800px;
            color: #fff;
            margin-bottom: 1rem;
            letter-spacing: -0.5px;
        }
        .meta-stats {
            display: flex;
            flex-wrap: wrap;
            gap: 1.5rem;
            font-size: 0.9rem;
            color: #cbd5e1;
        }
        .meta-stats span {
            display: flex;
            align-items: center;
            gap: 0.4rem;
        }
        /* 文章内容区 */
        .article-main {
            margin-top: -2rem;
            position: relative;
            z-index: 5;
            padding-bottom: 4rem;
        }
        .article-card {
            background: var(--surface-card);
            border-radius: var(--radius-lg);
            padding: 2.5rem;
            box-shadow: var(--shadow-elevated);
            color: var(--text-on-card);
            line-height: 1.8;
            font-size: 1.05rem;
        }
        .article-card h2, .article-card h3 {
            color: #0f172a;
            margin: 2rem 0 0.8rem;
        }
        .article-card p {
            margin-bottom: 1.2rem;
        }
        .article-card a {
            color: var(--primary);
            text-decoration: underline;
        }
        .not-found {
            text-align: center;
            padding: 4rem 2rem;
            background: var(--surface-elevated);
            border-radius: var(--radius-lg);
            border: 1px solid var(--border-dark);
        }
        .not-found h2 {
            font-size: 2rem;
            color: var(--text-on-dark);
            margin-bottom: 1rem;
        }
        .btn-primary {
            display: inline-block;
            background: var(--primary);
            color: #fff;
            padding: 0.75rem 2rem;
            border-radius: 40px;
            font-weight: 600;
            transition: all var(--transition-base);
            box-shadow: 0 8px 20px -6px rgba(14,165,233,0.4);
        }
        .btn-primary:hover {
            background: var(--primary-hover);
            transform: translateY(-2px);
            box-shadow: 0 12px 24px -6px rgba(14,165,233,0.6);
        }
        /* CTA 条 */
        .cta-strip {
            background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
            border: 1px solid var(--border-dark);
            border-radius: var(--radius-lg);
            padding: 2.5rem 2rem;
            text-align: center;
            margin: 3rem 0 2rem;
        }
        .cta-strip h3 {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: 0.75rem;
        }
        .cta-strip p {
            color: var(--text-muted-dark);
            margin-bottom: 1.5rem;
        }
        /* 页脚 */
        .site-footer {
            background: #0b1120;
            border-top: 1px solid #1e293b;
            padding: 2.5rem 0;
            color: #94a3b8;
        }
        .footer-inner {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 1.2rem;
        }
        .footer-logo {
            font-weight: 700;
            font-size: 1.25rem;
            background: linear-gradient(135deg, #0ea5e9, #6366f1);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .footer-links {
            display: flex;
            gap: 2rem;
        }
        .footer-links a {
            color: #94a3b8;
            transition: color 0.2s;
        }
        .footer-links a:hover { color: #e2e8f0; }
        .footer-copy { font-size: 0.85rem; }
        /* 响应式 */
        @media (max-width: 1024px) {
            .article-banner h1 { font-size: 2rem; }
        }
        @media (max-width: 768px) {
            .header-inner { height: auto; padding: 1rem 0; }
            .nav-tabs { display: none; }
            .mobile-menu-btn { display: block; }
            .article-banner { min-height: 260px; padding-bottom: 2rem; }
            .article-banner h1 { font-size: 1.8rem; }
            .article-card { padding: 1.5rem; font-size: 1rem; }
        }
        @media (max-width: 520px) {
            .article-banner h1 { font-size: 1.5rem; }
            .meta-stats { flex-direction: column; gap: 0.4rem; }
        }
        /* 移动端导航菜单 */
        .mobile-nav {
            display: none;
            flex-direction: column;
            background: #1e293b;
            border-radius: 12px;
            margin-top: 0.75rem;
            padding: 0.75rem;
            gap: 0.5rem;
        }
        .mobile-nav a {
            padding: 0.6rem 1rem;
            border-radius: 40px;
            color: #cbd5e1;
        }
        .mobile-nav a.active {
            background: var(--primary);
            color: #fff;
            font-weight: 600;
        }
        .show-mobile-nav { display: flex; }

/* roulang page: category1 */
:root {
            --primary: #0284c7;
            --primary-light: #0ea5e9;
            --primary-dark: #0369a1;
            --accent: #6366f1;
            --accent-light: #818cf8;
            --bg-main: #f8fafc;
            --bg-white: #ffffff;
            --bg-dark: #0f172a;
            --bg-dark-card: #1e293b;
            --bg-dark-elevated: #273348;
            --text-primary: #1e293b;
            --text-secondary: #475569;
            --text-tertiary: #94a3b8;
            --text-light: #e2e8f0;
            --text-light-secondary: #94a3b8;
            --border-light: #e2e8f0;
            --border-medium: #cbd5e1;
            --border-dark: #334155;
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
            --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.04);
            --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.1), 0 4px 8px rgba(0, 0, 0, 0.06);
            --shadow-glow: 0 0 40px rgba(2, 132, 199, 0.15), 0 8px 24px rgba(0, 0, 0, 0.1);
            --radius-xs: 6px;
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
            --radius-xl: 20px;
            --radius-full: 9999px;
            --spacing-xs: 8px;
            --spacing-sm: 16px;
            --spacing-md: 24px;
            --spacing-lg: 40px;
            --spacing-xl: 56px;
            --spacing-2xl: 80px;
            --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', system-ui, -apple-system, sans-serif;
        }

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

        html {
            scroll-behavior: smooth;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        body {
            font-family: var(--font-sans);
            font-size: 16px;
            line-height: 1.7;
            color: var(--text-primary);
            background-color: var(--bg-main);
            min-height: 100vh;
        }

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

        a {
            text-decoration: none;
            color: inherit;
            transition: color var(--transition-fast);
        }

        button {
            cursor: pointer;
            font-family: inherit;
            border: none;
            outline: none;
        }

        input {
            font-family: inherit;
            outline: none;
        }

        .container {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 var(--spacing-md);
        }

        @media (max-width: 1024px) {
            .container {
                padding: 0 var(--spacing-sm);
            }
        }

        @media (max-width: 768px) {
            .container {
                padding: 0 var(--spacing-xs);
            }
        }

        /* ========== HEADER ========== */
        .site-header {
            background: var(--bg-white);
            border-bottom: 1px solid var(--border-light);
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: var(--shadow-sm);
            transition: box-shadow var(--transition-smooth);
        }

        .site-header.scrolled {
            box-shadow: var(--shadow-md);
        }

        .header-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 14px 0;
            gap: var(--spacing-md);
        }

        .header-logo {
            font-size: 1.35rem;
            font-weight: 700;
            color: var(--text-primary);
            letter-spacing: -0.02em;
            white-space: nowrap;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: color var(--transition-fast);
        }

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

        .header-logo .logo-icon {
            width: 34px;
            height: 34px;
            background: linear-gradient(135deg, var(--primary), var(--accent));
            border-radius: var(--radius-xs);
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-size: 0.85rem;
            font-weight: 700;
            flex-shrink: 0;
        }

        /* 分段标签导航 */
        .nav-tabs {
            display: flex;
            align-items: center;
            gap: 6px;
            background: var(--bg-main);
            border-radius: var(--radius-full);
            padding: 5px;
            border: 1px solid var(--border-light);
        }

        .nav-tabs a {
            display: inline-flex;
            align-items: center;
            padding: 10px 22px;
            font-size: 0.925rem;
            font-weight: 500;
            color: var(--text-secondary);
            border-radius: var(--radius-full);
            transition: all var(--transition-fast);
            white-space: nowrap;
            position: relative;
        }

        .nav-tabs a:hover {
            color: var(--text-primary);
            background: rgba(2, 132, 199, 0.06);
        }

        .nav-tabs a.active {
            background: var(--bg-white);
            color: var(--primary);
            font-weight: 600;
            box-shadow: var(--shadow-sm);
        }

        .header-actions {
            display: flex;
            align-items: center;
            gap: var(--spacing-xs);
            flex-shrink: 0;
        }

        .btn-outline-sm {
            padding: 9px 18px;
            font-size: 0.875rem;
            font-weight: 500;
            border-radius: var(--radius-full);
            border: 1.5px solid var(--border-medium);
            background: transparent;
            color: var(--text-primary);
            transition: all var(--transition-fast);
            white-space: nowrap;
        }

        .btn-outline-sm:hover {
            border-color: var(--primary);
            color: var(--primary);
            background: rgba(2, 132, 199, 0.04);
        }

        .btn-primary-sm {
            padding: 9px 18px;
            font-size: 0.875rem;
            font-weight: 600;
            border-radius: var(--radius-full);
            background: linear-gradient(135deg, var(--primary), var(--primary-light));
            color: #fff;
            transition: all var(--transition-fast);
            white-space: nowrap;
            box-shadow: 0 2px 8px rgba(2, 132, 199, 0.3);
        }

        .btn-primary-sm:hover {
            box-shadow: 0 4px 16px rgba(2, 132, 199, 0.45);
            transform: translateY(-1px);
        }

        /* 移动端汉堡菜单 */
        .mobile-menu-toggle {
            display: none;
            background: none;
            border: none;
            font-size: 1.4rem;
            color: var(--text-primary);
            padding: 8px;
            cursor: pointer;
            border-radius: var(--radius-xs);
            transition: background var(--transition-fast);
        }

        .mobile-menu-toggle:hover {
            background: var(--bg-main);
        }

        @media (max-width: 768px) {
            .header-inner {
                flex-wrap: wrap;
                padding: 10px 0;
                gap: 10px;
            }

            .header-logo {
                font-size: 1.15rem;
            }

            .header-logo .logo-icon {
                width: 28px;
                height: 28px;
                font-size: 0.7rem;
            }

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

            .nav-tabs {
                display: none;
                width: 100%;
                order: 3;
                flex-direction: row;
                overflow-x: auto;
                -webkit-overflow-scrolling: touch;
                gap: 4px;
                padding: 4px;
                border-radius: var(--radius-md);
                scrollbar-width: none;
            }

            .nav-tabs::-webkit-scrollbar {
                display: none;
            }

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

            .nav-tabs a {
                padding: 8px 16px;
                font-size: 0.85rem;
                flex-shrink: 0;
            }

            .header-actions {
                gap: 6px;
            }

            .btn-outline-sm,
            .btn-primary-sm {
                padding: 7px 14px;
                font-size: 0.8rem;
            }
        }

        @media (max-width: 520px) {
            .header-logo {
                font-size: 1rem;
            }

            .header-actions .btn-outline-sm {
                display: none;
            }

            .btn-primary-sm {
                padding: 7px 12px;
                font-size: 0.78rem;
            }
        }

        /* ========== PAGE BANNER ========== */
        .page-banner {
            position: relative;
            background: var(--bg-dark);
            background-image: url('/assets/images/backpic/back-1.png');
            background-size: cover;
            background-position: center;
            padding: var(--spacing-2xl) 0;
            overflow: hidden;
        }

        .page-banner::before {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(135deg, rgba(15, 23, 42, 0.88) 0%, rgba(15, 23, 42, 0.75) 40%, rgba(30, 41, 59, 0.7) 100%);
            z-index: 1;
        }

        .page-banner::after {
            content: '';
            position: absolute;
            top: -60%;
            right: -20%;
            width: 600px;
            height: 600px;
            border-radius: 50%;
            background: radial-gradient(circle, rgba(2, 132, 199, 0.18) 0%, transparent 70%);
            z-index: 1;
            pointer-events: none;
        }

        .banner-content {
            position: relative;
            z-index: 2;
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            gap: var(--spacing-sm);
        }

        .breadcrumb {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 0.875rem;
            color: var(--text-light-secondary);
            margin-bottom: 4px;
        }

        .breadcrumb a {
            color: var(--text-light-secondary);
            transition: color var(--transition-fast);
        }

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

        .breadcrumb .separator {
            color: rgba(148, 163, 184, 0.5);
            font-size: 0.7rem;
        }

        .breadcrumb .current {
            color: var(--text-light);
        }

        .page-banner .banner-icon {
            width: 64px;
            height: 64px;
            background: linear-gradient(135deg, rgba(2, 132, 199, 0.3), rgba(99, 102, 241, 0.3));
            border: 1.5px solid rgba(255, 255, 255, 0.15);
            border-radius: var(--radius-md);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.6rem;
            color: var(--primary-light);
            backdrop-filter: blur(8px);
            margin-bottom: 4px;
        }

        .page-banner h1 {
            font-size: 2.6rem;
            font-weight: 700;
            color: #ffffff;
            letter-spacing: -0.03em;
            line-height: 1.25;
        }

        .page-banner .banner-subtitle {
            font-size: 1.1rem;
            color: var(--text-light-secondary);
            max-width: 560px;
            line-height: 1.6;
        }

        .banner-stats-row {
            display: flex;
            gap: var(--spacing-lg);
            margin-top: var(--spacing-sm);
            flex-wrap: wrap;
            justify-content: center;
        }

        .banner-stat-item {
            display: flex;
            align-items: center;
            gap: 8px;
            color: var(--text-light-secondary);
            font-size: 0.9rem;
        }

        .banner-stat-item .stat-value {
            font-weight: 700;
            color: var(--primary-light);
            font-size: 1.15rem;
        }

        @media (max-width: 768px) {
            .page-banner {
                padding: var(--spacing-xl) 0;
            }

            .page-banner h1 {
                font-size: 1.8rem;
            }

            .page-banner .banner-subtitle {
                font-size: 0.95rem;
            }

            .page-banner .banner-icon {
                width: 48px;
                height: 48px;
                font-size: 1.2rem;
            }

            .banner-stats-row {
                gap: var(--spacing-sm);
            }
        }

        @media (max-width: 520px) {
            .page-banner h1 {
                font-size: 1.5rem;
            }

            .page-banner .banner-subtitle {
                font-size: 0.875rem;
            }
        }

        /* ========== MAIN CONTENT AREA ========== */
        .main-content {
            padding: var(--spacing-xl) 0 var(--spacing-2xl);
        }

        .content-layout {
            display: grid;
            grid-template-columns: 1fr 340px;
            gap: var(--spacing-lg);
            align-items: start;
        }

        @media (max-width: 1024px) {
            .content-layout {
                grid-template-columns: 1fr;
                gap: var(--spacing-md);
            }
        }

        /* ========== FILTER BAR ========== */
        .filter-bar {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: var(--spacing-sm);
            margin-bottom: var(--spacing-md);
            flex-wrap: wrap;
        }

        .filter-tags {
            display: flex;
            gap: 6px;
            flex-wrap: wrap;
        }

        .filter-tag {
            padding: 7px 16px;
            font-size: 0.85rem;
            font-weight: 500;
            border-radius: var(--radius-full);
            border: 1.5px solid var(--border-light);
            background: var(--bg-white);
            color: var(--text-secondary);
            cursor: pointer;
            transition: all var(--transition-fast);
            white-space: nowrap;
        }

        .filter-tag:hover {
            border-color: var(--primary-light);
            color: var(--primary);
        }

        .filter-tag.active {
            background: var(--primary);
            border-color: var(--primary);
            color: #fff;
            font-weight: 600;
        }

        .filter-search {
            position: relative;
            flex-shrink: 0;
        }

        .filter-search input {
            padding: 9px 16px 9px 38px;
            font-size: 0.875rem;
            border-radius: var(--radius-full);
            border: 1.5px solid var(--border-light);
            background: var(--bg-white);
            color: var(--text-primary);
            width: 240px;
            transition: all var(--transition-fast);
        }

        .filter-search input:focus {
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.08);
        }

        .filter-search i {
            position: absolute;
            left: 14px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-tertiary);
            font-size: 0.9rem;
            pointer-events: none;
        }

        @media (max-width: 768px) {
            .filter-bar {
                flex-direction: column;
                align-items: stretch;
            }

            .filter-search input {
                width: 100%;
            }

            .filter-tags {
                overflow-x: auto;
                flex-wrap: nowrap;
                -webkit-overflow-scrolling: touch;
                padding-bottom: 4px;
            }

            .filter-tag {
                flex-shrink: 0;
            }
        }

        /* ========== ARTICLE CARDS GRID ========== */
        .articles-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: var(--spacing-md);
        }

        @media (max-width: 768px) {
            .articles-grid {
                grid-template-columns: 1fr;
                gap: var(--spacing-sm);
            }
        }

        .article-card {
            background: var(--bg-white);
            border-radius: var(--radius-lg);
            overflow: hidden;
            border: 1px solid var(--border-light);
            transition: all var(--transition-smooth);
            display: flex;
            flex-direction: column;
            box-shadow: var(--shadow-sm);
        }

        .article-card:hover {
            box-shadow: var(--shadow-lg);
            transform: translateY(-3px);
            border-color: var(--border-medium);
        }

        .article-card-image {
            position: relative;
            aspect-ratio: 16 / 9;
            overflow: hidden;
        }

        .article-card-image img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: transform var(--transition-smooth);
        }

        .article-card:hover .article-card-image img {
            transform: scale(1.04);
        }

        .article-card-tag {
            position: absolute;
            top: 14px;
            left: 14px;
            padding: 5px 12px;
            font-size: 0.78rem;
            font-weight: 600;
            border-radius: var(--radius-full);
            background: rgba(15, 23, 42, 0.8);
            color: var(--primary-light);
            backdrop-filter: blur(6px);
            border: 1px solid rgba(255, 255, 255, 0.1);
            z-index: 1;
        }

        .article-card-body {
            padding: var(--spacing-sm) var(--spacing-md) var(--spacing-md);
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: 8px;
        }

        .article-card-body h3 {
            font-size: 1.1rem;
            font-weight: 600;
            color: var(--text-primary);
            line-height: 1.4;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }

        .article-card-body h3 a {
            color: inherit;
            transition: color var(--transition-fast);
        }

        .article-card-body h3 a:hover {
            color: var(--primary);
        }

        .article-card-excerpt {
            font-size: 0.9rem;
            color: var(--text-secondary);
            line-height: 1.6;
            display: -webkit-box;
            -webkit-line-clamp: 3;
            -webkit-box-orient: vertical;
            overflow: hidden;
            flex: 1;
        }

        .article-card-meta {
            display: flex;
            align-items: center;
            gap: var(--spacing-sm);
            font-size: 0.8rem;
            color: var(--text-tertiary);
            padding-top: 8px;
            border-top: 1px solid var(--border-light);
        }

        .article-card-meta span {
            display: flex;
            align-items: center;
            gap: 4px;
        }

        .article-card-meta i {
            font-size: 0.75rem;
        }

        /* ========== SIDEBAR ========== */
        .sidebar {
            display: flex;
            flex-direction: column;
            gap: var(--spacing-md);
            position: sticky;
            top: 90px;
        }

        @media (max-width: 1024px) {
            .sidebar {
                position: static;
                top: auto;
            }
        }

        .sidebar-card {
            background: var(--bg-white);
            border-radius: var(--radius-lg);
            border: 1px solid var(--border-light);
            padding: var(--spacing-md);
            box-shadow: var(--shadow-sm);
        }

        .sidebar-card h4 {
            font-size: 1rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: var(--spacing-sm);
            padding-bottom: var(--spacing-xs);
            border-bottom: 2px solid var(--primary-light);
            display: inline-block;
        }

        .hot-list {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 14px;
        }

        .hot-list-item {
            display: flex;
            gap: 12px;
            align-items: flex-start;
            padding-bottom: 14px;
            border-bottom: 1px solid var(--border-light);
            transition: all var(--transition-fast);
            cursor: pointer;
        }

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

        .hot-list-item:hover .hot-list-title {
            color: var(--primary);
        }

        .hot-list-thumb {
            width: 72px;
            height: 54px;
            border-radius: var(--radius-xs);
            overflow: hidden;
            flex-shrink: 0;
        }

        .hot-list-thumb img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }

        .hot-list-info {
            flex: 1;
            min-width: 0;
        }

        .hot-list-title {
            font-size: 0.88rem;
            font-weight: 500;
            color: var(--text-primary);
            line-height: 1.4;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
            transition: color var(--transition-fast);
        }

        .hot-list-date {
            font-size: 0.78rem;
            color: var(--text-tertiary);
            margin-top: 4px;
        }

        .tag-cloud {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
        }

        .tag-cloud-item {
            padding: 6px 14px;
            font-size: 0.82rem;
            font-weight: 500;
            border-radius: var(--radius-full);
            background: var(--bg-main);
            color: var(--text-secondary);
            border: 1px solid var(--border-light);
            transition: all var(--transition-fast);
            cursor: pointer;
        }

        .tag-cloud-item:hover {
            background: rgba(2, 132, 199, 0.08);
            border-color: var(--primary-light);
            color: var(--primary);
        }

        @media (max-width: 1024px) {
            .sidebar {
                display: grid;
                grid-template-columns: repeat(2, 1fr);
                gap: var(--spacing-sm);
            }
        }

        @media (max-width: 768px) {
            .sidebar {
                grid-template-columns: 1fr;
            }
        }

        /* ========== DARK STATS BAND ========== */
        .stats-band {
            background: var(--bg-dark);
            padding: var(--spacing-xl) 0;
            position: relative;
            overflow: hidden;
        }

        .stats-band::before {
            content: '';
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 500px;
            height: 2px;
            background: linear-gradient(90deg, transparent, rgba(2, 132, 199, 0.5), transparent);
        }

        .stats-band .section-label {
            text-align: center;
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--primary-light);
            text-transform: uppercase;
            letter-spacing: 0.08em;
            margin-bottom: var(--spacing-xs);
        }

        .stats-band h2 {
            text-align: center;
            font-size: 1.8rem;
            font-weight: 700;
            color: #ffffff;
            margin-bottom: var(--spacing-lg);
        }

        .stats-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: var(--spacing-md);
        }

        @media (max-width: 1024px) {
            .stats-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: var(--spacing-sm);
            }
        }

        @media (max-width: 520px) {
            .stats-grid {
                grid-template-columns: 1fr 1fr;
                gap: var(--spacing-xs);
            }

            .stats-band h2 {
                font-size: 1.4rem;
            }
        }

        .stat-card {
            background: var(--bg-dark-card);
            border: 1px solid var(--border-dark);
            border-radius: var(--radius-lg);
            padding: var(--spacing-md);
            text-align: center;
            transition: all var(--transition-smooth);
            position: relative;
            overflow: hidden;
        }

        .stat-card::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 20%;
            width: 60%;
            height: 2px;
            background: linear-gradient(90deg, transparent, rgba(2, 132, 199, 0.6), transparent);
            border-radius: 1px;
        }

        .stat-card:hover {
            border-color: rgba(2, 132, 199, 0.4);
            box-shadow: var(--shadow-glow);
            transform: translateY(-2px);
        }

        .stat-card .stat-number {
            font-size: 2.2rem;
            font-weight: 700;
            color: var(--primary-light);
            letter-spacing: -0.02em;
        }

        .stat-card .stat-label {
            font-size: 0.9rem;
            color: var(--text-light-secondary);
            margin-top: 6px;
        }

        /* ========== SUBSCRIBE CTA ========== */
        .cta-band {
            background: linear-gradient(135deg, #0369a1 0%, #0284c7 40%, #6366f1 100%);
            padding: var(--spacing-xl) 0;
            position: relative;
            overflow: hidden;
        }

        .cta-band::before {
            content: '';
            position: absolute;
            top: -40%;
            left: -20%;
            width: 500px;
            height: 500px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.04);
            pointer-events: none;
        }

        .cta-band-inner {
            position: relative;
            z-index: 1;
            text-align: center;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--spacing-sm);
        }

        .cta-band h2 {
            font-size: 1.8rem;
            font-weight: 700;
            color: #ffffff;
        }

        .cta-band p {
            color: rgba(255, 255, 255, 0.8);
            font-size: 1rem;
            max-width: 500px;
        }

        .cta-form {
            display: flex;
            gap: 10px;
            max-width: 440px;
            width: 100%;
        }

        .cta-form input {
            flex: 1;
            padding: 12px 18px;
            font-size: 0.95rem;
            border-radius: var(--radius-full);
            border: 1.5px solid rgba(255, 255, 255, 0.3);
            background: rgba(255, 255, 255, 0.15);
            color: #fff;
            backdrop-filter: blur(4px);
            transition: all var(--transition-fast);
        }

        .cta-form input::placeholder {
            color: rgba(255, 255, 255, 0.55);
        }

        .cta-form input:focus {
            border-color: #fff;
            background: rgba(255, 255, 255, 0.22);
            box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.1);
        }

        .btn-cta {
            padding: 12px 28px;
            font-size: 0.95rem;
            font-weight: 600;
            border-radius: var(--radius-full);
            background: #ffffff;
            color: var(--primary-dark);
            transition: all var(--transition-fast);
            white-space: nowrap;
            box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
        }

        .btn-cta:hover {
            background: #f1f5f9;
            box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
            transform: translateY(-2px);
        }

        @media (max-width: 520px) {
            .cta-form {
                flex-direction: column;
                gap: 8px;
            }

            .cta-band h2 {
                font-size: 1.4rem;
            }

            .btn-cta {
                width: 100%;
                text-align: center;
            }
        }

        /* ========== FAQ SECTION ========== */
        .faq-section {
            padding: var(--spacing-xl) 0;
            background: var(--bg-white);
        }

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

        .faq-section .section-label {
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--primary);
            text-transform: uppercase;
            letter-spacing: 0.08em;
            margin-bottom: 6px;
        }

        .faq-section h2 {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--text-primary);
        }

        .faq-list {
            max-width: 760px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: var(--spacing-xs);
        }

        .faq-item {
            background: var(--bg-main);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-md);
            overflow: hidden;
            transition: all var(--transition-fast);
        }

        .faq-item:hover {
            border-color: var(--border-medium);
            box-shadow: var(--shadow-sm);
        }

        .faq-question {
            padding: var(--spacing-sm) var(--spacing-md);
            font-weight: 600;
            font-size: 1rem;
            color: var(--text-primary);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: var(--spacing-sm);
            transition: color var(--transition-fast);
            background: none;
            width: 100%;
            text-align: left;
            border: none;
            font-family: inherit;
        }

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

        .faq-question i {
            font-size: 0.8rem;
            color: var(--text-tertiary);
            transition: transform var(--transition-fast);
            flex-shrink: 0;
        }

        .faq-answer {
            padding: 0 var(--spacing-md) var(--spacing-md);
            font-size: 0.925rem;
            color: var(--text-secondary);
            line-height: 1.7;
            display: none;
        }

        .faq-item.open .faq-answer {
            display: block;
        }

        .faq-item.open .faq-question i {
            transform: rotate(180deg);
            color: var(--primary);
        }

        .faq-item.open {
            border-color: var(--primary-light);
            box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.05);
        }

        @media (max-width: 768px) {
            .faq-section h2 {
                font-size: 1.4rem;
            }

            .faq-question {
                font-size: 0.925rem;
                padding: var(--spacing-sm);
            }

            .faq-answer {
                padding: 0 var(--spacing-sm) var(--spacing-sm);
            }
        }

        /* ========== PAGINATION ========== */
        .pagination {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
            margin-top: var(--spacing-lg);
            flex-wrap: wrap;
        }

        .pagination a,
        .pagination span {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            min-width: 40px;
            height: 40px;
            padding: 0 12px;
            font-size: 0.9rem;
            font-weight: 500;
            border-radius: var(--radius-sm);
            border: 1.5px solid var(--border-light);
            background: var(--bg-white);
            color: var(--text-secondary);
            transition: all var(--transition-fast);
        }

        .pagination a:hover {
            border-color: var(--primary-light);
            color: var(--primary);
            background: rgba(2, 132, 199, 0.04);
        }

        .pagination .current {
            background: var(--primary);
            border-color: var(--primary);
            color: #fff;
            font-weight: 600;
        }

        .pagination .disabled {
            opacity: 0.4;
            pointer-events: none;
        }

        /* ========== FOOTER ========== */
        .site-footer {
            background: var(--bg-dark);
            padding: var(--spacing-lg) 0;
            border-top: 1px solid var(--border-dark);
        }

        .footer-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: var(--spacing-sm);
        }

        .footer-logo {
            font-size: 1.1rem;
            font-weight: 700;
            color: #ffffff;
            letter-spacing: -0.02em;
        }

        .footer-links {
            display: flex;
            gap: var(--spacing-md);
            flex-wrap: wrap;
        }

        .footer-links a {
            font-size: 0.875rem;
            color: var(--text-light-secondary);
            transition: color var(--transition-fast);
        }

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

        .footer-copy {
            font-size: 0.82rem;
            color: var(--text-light-secondary);
            opacity: 0.7;
        }

        @media (max-width: 768px) {
            .footer-inner {
                flex-direction: column;
                text-align: center;
                gap: 12px;
            }

            .footer-links {
                justify-content: center;
                gap: var(--spacing-sm);
            }
        }

        /* ========== BACK TO TOP ========== */
        .back-to-top {
            position: fixed;
            bottom: 28px;
            right: 28px;
            width: 44px;
            height: 44px;
            border-radius: 50%;
            background: var(--primary);
            color: #fff;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1rem;
            box-shadow: var(--shadow-md);
            opacity: 0;
            visibility: hidden;
            transform: translateY(12px);
            transition: all var(--transition-smooth);
            z-index: 999;
            cursor: pointer;
            border: none;
        }

        .back-to-top.visible {
            opacity: 1;
            visibility: visible;
            transform: translateY(0);
        }

        .back-to-top:hover {
            background: var(--primary-dark);
            box-shadow: var(--shadow-lg);
            transform: translateY(-3px);
        }

        @media (max-width: 520px) {
            .back-to-top {
                bottom: 18px;
                right: 14px;
                width: 38px;
                height: 38px;
                font-size: 0.85rem;
            }
        }