/* roulang page: index */
/* ===== Design Variables ===== */
    :root {
        --primary: #E8502A;
        --primary-dark: #D0441F;
        --primary-light: #F8A07C;
        --primary-gradient: linear-gradient(135deg, #E8502A 0%, #FF6B35 100%);
        --secondary: #1E2A4A;
        --secondary-light: #2C3E6B;
        --bg: #F7F8FC;
        --bg-alt: #FFFFFF;
        --bg-dark: #1E2A4A;
        --text: #1E1E2E;
        --text-light: #6B7280;
        --text-white: #FFFFFF;
        --border: #E5E7EB;
        --radius: 12px;
        --radius-sm: 8px;
        --radius-lg: 20px;
        --shadow: 0 4px 20px rgba(0,0,0,0.08);
        --shadow-lg: 0 8px 40px rgba(0,0,0,0.12);
        --shadow-hover: 0 12px 48px rgba(0,0,0,0.15);
        --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
        --nav-width: 240px;
        --nav-collapsed: 0px;
        --header-height: 0px;
    }

    /* ===== Reset & Base ===== */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
    body {
        font-family: var(--font);
        background: var(--bg);
        color: var(--text);
        line-height: 1.6;
        font-size: 16px;
        display: flex;
        min-height: 100vh;
    }
    a { color: inherit; text-decoration: none; transition: var(--transition); }
    a:hover { color: var(--primary); }
    img { max-width: 100%; height: auto; display: block; }
    button, input, textarea { font-family: inherit; font-size: inherit; border: none; outline: none; }
    button { cursor: pointer; background: none; }
    ul, ol { list-style: none; }
    h1, h2, h3, h4, h5, h6 { line-height: 1.25; font-weight: 700; color: var(--text); }
    h1 { font-size: 2.75rem; }
    h2 { font-size: 2.125rem; margin-bottom: 1rem; }
    h3 { font-size: 1.5rem; }
    h4 { font-size: 1.25rem; }
    p { margin-bottom: 1rem; color: var(--text-light); }
    .container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 24px; }

    /* ===== Layout: App Shell ===== */
    .app-shell { display: flex; width: 100%; min-height: 100vh; }

    /* ===== Left Navigation ===== */
    .app-nav {
        position: fixed; top: 0; left: 0; width: var(--nav-width); height: 100vh;
        background: var(--secondary); color: var(--text-white);
        display: flex; flex-direction: column; z-index: 1000;
        transition: transform 0.3s ease, box-shadow 0.3s ease;
        box-shadow: 2px 0 20px rgba(0,0,0,0.1);
    }
    .app-nav .nav-brand {
        padding: 28px 20px 20px; border-bottom: 1px solid rgba(255,255,255,0.08);
        display: flex; align-items: center; gap: 12px;
    }
    .app-nav .nav-brand .brand-icon {
        width: 40px; height: 40px; background: var(--primary-gradient);
        border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center;
        font-size: 20px; color: #fff; flex-shrink: 0;
    }
    .app-nav .nav-brand .brand-text {
        font-size: 1.05rem; font-weight: 700; line-height: 1.3;
        color: var(--text-white); letter-spacing: 0.5px;
    }
    .app-nav .nav-menu { flex: 1; padding: 16px 12px; overflow-y: auto; }
    .app-nav .nav-menu .nav-item {
        display: flex; align-items: center; gap: 12px;
        padding: 12px 16px; border-radius: var(--radius-sm);
        color: rgba(255,255,255,0.7); font-size: 0.95rem; font-weight: 500;
        transition: var(--transition); margin-bottom: 4px; cursor: pointer;
    }
    .app-nav .nav-menu .nav-item i { width: 20px; text-align: center; font-size: 1.05rem; }
    .app-nav .nav-menu .nav-item:hover { background: rgba(255,255,255,0.08); color: #fff; }
    .app-nav .nav-menu .nav-item.active {
        background: var(--primary-gradient); color: #fff; box-shadow: 0 4px 16px rgba(232,80,42,0.35);
    }
    .app-nav .nav-footer {
        padding: 16px 20px; border-top: 1px solid rgba(255,255,255,0.08);
        font-size: 0.75rem; color: rgba(255,255,255,0.4); text-align: center;
    }

    /* ===== Main Content ===== */
    .app-main {
        margin-left: var(--nav-width); flex: 1; min-height: 100vh;
        display: flex; flex-direction: column;
        transition: margin-left 0.3s ease;
    }

    /* ===== Mobile Header ===== */
    .mobile-header {
        display: none; position: sticky; top: 0; z-index: 999;
        background: var(--secondary); padding: 12px 20px;
        align-items: center; justify-content: space-between;
        box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    }
    .mobile-header .m-brand { color: #fff; font-weight: 700; font-size: 1rem; display: flex; align-items: center; gap: 10px; }
    .mobile-header .m-brand i { color: var(--primary); font-size: 1.2rem; }
    .mobile-header .menu-toggle {
        color: #fff; font-size: 1.4rem; padding: 4px 8px; border-radius: 6px;
        background: rgba(255,255,255,0.1); transition: var(--transition);
    }
    .mobile-header .menu-toggle:hover { background: rgba(255,255,255,0.2); }

    /* ===== Mobile Nav Overlay ===== */
    .nav-overlay {
        display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%;
        background: rgba(0,0,0,0.5); z-index: 999; opacity: 0; transition: opacity 0.3s ease;
    }
    .nav-overlay.open { opacity: 1; }

    /* ===== Hero ===== */
    .hero {
        position: relative; padding: 100px 0 80px; overflow: hidden;
        background: var(--bg-dark);
        background-image: url('/assets/images/backpic/back-1.png');
        background-size: cover; background-position: center; background-blend-mode: overlay;
    }
    .hero::before {
        content: ''; position: absolute; inset: 0;
        background: linear-gradient(135deg, rgba(30,42,74,0.88) 0%, rgba(30,42,74,0.6) 100%);
        z-index: 1;
    }
    .hero .container { position: relative; z-index: 2; text-align: center; }
    .hero h1 {
        font-size: 3.25rem; font-weight: 800; color: var(--text-white);
        margin-bottom: 1rem; letter-spacing: -0.5px;
    }
    .hero h1 span { background: var(--primary-gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
    .hero p {
        font-size: 1.2rem; color: rgba(255,255,255,0.75);
        max-width: 640px; margin: 0 auto 2rem;
    }
    .hero .hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
    .hero .hero-actions .btn { padding: 14px 36px; font-size: 1.05rem; border-radius: 50px; font-weight: 600; }
    .hero .hero-actions .btn-primary {
        background: var(--primary-gradient); color: #fff; box-shadow: 0 8px 32px rgba(232,80,42,0.4);
    }
    .hero .hero-actions .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 40px rgba(232,80,42,0.5); }
    .hero .hero-actions .btn-outline {
        background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.3);
    }
    .hero .hero-actions .btn-outline:hover { border-color: var(--primary); background: rgba(232,80,42,0.15); }
    .hero .hero-stats {
        display: flex; justify-content: center; gap: 48px; margin-top: 48px;
        flex-wrap: wrap;
    }
    .hero .hero-stats .stat-item { text-align: center; }
    .hero .hero-stats .stat-num {
        font-size: 2.25rem; font-weight: 800; color: #fff;
        background: var(--primary-gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
    }
    .hero .hero-stats .stat-label { font-size: 0.9rem; color: rgba(255,255,255,0.6); margin-top: 4px; }

    /* ===== Section Spacing ===== */
    .section { padding: 80px 0; }
    .section-alt { background: var(--bg-alt); }
    .section-dark { background: var(--bg-dark); color: var(--text-white); }
    .section-title { text-align: center; margin-bottom: 48px; }
    .section-title h2 { font-size: 2.125rem; font-weight: 700; }
    .section-title p { max-width: 560px; margin: 0 auto; color: var(--text-light); font-size: 1.05rem; }
    .section-dark .section-title h2 { color: #fff; }
    .section-dark .section-title p { color: rgba(255,255,255,0.6); }

    /* ===== Cards ===== */
    .card {
        background: var(--bg-alt); border-radius: var(--radius);
        box-shadow: var(--shadow); overflow: hidden;
        transition: var(--transition);
        border: 1px solid var(--border);
    }
    .card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
    .card .card-img { width: 100%; height: 200px; object-fit: cover; }
    .card .card-body { padding: 24px; }
    .card .card-body h3 { font-size: 1.15rem; margin-bottom: 8px; }
    .card .card-body p { font-size: 0.9rem; color: var(--text-light); margin-bottom: 0; }
    .card .card-tag {
        display: inline-block; padding: 4px 12px; border-radius: 50px;
        font-size: 0.75rem; font-weight: 600; background: rgba(232,80,42,0.1); color: var(--primary);
        margin-bottom: 10px;
    }

    /* ===== Card Grid ===== */
    .card-grid { display: grid; gap: 28px; }
    .card-grid-3 { grid-template-columns: repeat(3, 1fr); }
    .card-grid-4 { grid-template-columns: repeat(4, 1fr); }
    .card-grid-2 { grid-template-columns: repeat(2, 1fr); }

    /* ===== Buttons ===== */
    .btn {
        display: inline-flex; align-items: center; gap: 8px;
        padding: 12px 28px; border-radius: 50px; font-weight: 600; font-size: 0.95rem;
        transition: var(--transition); cursor: pointer; border: none;
    }
    .btn-primary {
        background: var(--primary-gradient); color: #fff;
        box-shadow: 0 4px 16px rgba(232,80,42,0.3);
    }
    .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(232,80,42,0.4); color: #fff; }
    .btn-secondary {
        background: var(--secondary); color: #fff;
    }
    .btn-secondary:hover { background: var(--secondary-light); color: #fff; transform: translateY(-2px); }
    .btn-outline {
        background: transparent; color: var(--primary); border: 2px solid var(--primary);
    }
    .btn-outline:hover { background: var(--primary); color: #fff; }
    .btn-sm { padding: 8px 18px; font-size: 0.85rem; }
    .btn-lg { padding: 16px 40px; font-size: 1.1rem; }

    /* ===== Tags / Badges ===== */
    .tag {
        display: inline-block; padding: 4px 14px; border-radius: 50px;
        font-size: 0.8rem; font-weight: 600; background: rgba(232,80,42,0.1); color: var(--primary);
    }
    .tag-alt { background: rgba(30,42,74,0.08); color: var(--secondary); }
    .badge {
        display: inline-flex; align-items: center; gap: 4px;
        padding: 2px 12px; border-radius: 50px; font-size: 0.75rem; font-weight: 600;
    }
    .badge-primary { background: var(--primary); color: #fff; }
    .badge-secondary { background: var(--secondary); color: #fff; }

    /* ===== Feature Blocks ===== */
    .features-grid { display: grid; gap: 32px; grid-template-columns: repeat(3, 1fr); }
    .feature-card {
        text-align: center; padding: 36px 24px; border-radius: var(--radius);
        background: var(--bg-alt); border: 1px solid var(--border);
        transition: var(--transition);
    }
    .feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); border-color: var(--primary-light); }
    .feature-card .feat-icon {
        width: 64px; height: 64px; margin: 0 auto 20px;
        background: var(--primary-gradient); border-radius: 16px;
        display: flex; align-items: center; justify-content: center;
        font-size: 28px; color: #fff; box-shadow: 0 8px 24px rgba(232,80,42,0.25);
    }
    .feature-card h3 { font-size: 1.15rem; margin-bottom: 8px; }
    .feature-card p { font-size: 0.9rem; color: var(--text-light); margin-bottom: 0; }

    /* ===== Stats Block ===== */
    .stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
    .stat-card {
        text-align: center; padding: 36px 16px; border-radius: var(--radius);
        background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
        transition: var(--transition);
    }
    .stat-card:hover { background: rgba(255,255,255,0.1); transform: translateY(-4px); }
    .stat-card .stat-number {
        font-size: 2.5rem; font-weight: 800; color: #fff;
        background: var(--primary-gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
    }
    .stat-card .stat-label { font-size: 0.95rem; color: rgba(255,255,255,0.6); margin-top: 6px; }

    /* ===== Steps / Timeline ===== */
    .steps-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; position: relative; }
    .steps-grid::before {
        content: ''; position: absolute; top: 40px; left: 10%; right: 10%;
        height: 2px; background: linear-gradient(90deg, var(--primary), var(--primary-light), transparent);
        z-index: 0;
    }
    .step-card {
        text-align: center; position: relative; z-index: 1;
        padding: 24px 16px; background: var(--bg-alt); border-radius: var(--radius);
        border: 1px solid var(--border); transition: var(--transition);
    }
    .step-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
    .step-card .step-num {
        width: 48px; height: 48px; margin: 0 auto 16px;
        background: var(--primary-gradient); border-radius: 50%;
        display: flex; align-items: center; justify-content: center;
        font-size: 1.2rem; font-weight: 700; color: #fff;
        box-shadow: 0 4px 16px rgba(232,80,42,0.3);
    }
    .step-card h4 { font-size: 1rem; margin-bottom: 6px; }
    .step-card p { font-size: 0.85rem; color: var(--text-light); margin-bottom: 0; }

    /* ===== List / News ===== */
    .news-list { display: flex; flex-direction: column; gap: 16px; }
    .news-item {
        display: flex; align-items: center; gap: 16px;
        padding: 16px 20px; background: var(--bg-alt); border-radius: var(--radius-sm);
        border: 1px solid var(--border); transition: var(--transition);
    }
    .news-item:hover { transform: translateX(4px); box-shadow: var(--shadow); border-color: var(--primary-light); }
    .news-item .news-tag { flex-shrink: 0; }
    .news-item .news-title { flex: 1; font-weight: 500; font-size: 0.95rem; color: var(--text); }
    .news-item .news-title:hover { color: var(--primary); }
    .news-item .news-date { flex-shrink: 0; font-size: 0.8rem; color: var(--text-light); white-space: nowrap; }
    .news-empty {
        text-align: center; padding: 40px 20px; color: var(--text-light);
        background: var(--bg-alt); border-radius: var(--radius); border: 1px dashed var(--border);
    }

    /* ===== FAQ ===== */
    .faq-grid { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
    .faq-item {
        background: var(--bg-alt); border-radius: var(--radius-sm);
        border: 1px solid var(--border); overflow: hidden;
        transition: var(--transition);
    }
    .faq-item:hover { border-color: var(--primary-light); }
    .faq-item .faq-q {
        display: flex; justify-content: space-between; align-items: center;
        padding: 18px 24px; cursor: pointer; font-weight: 600; font-size: 1rem;
        transition: var(--transition); user-select: none;
    }
    .faq-item .faq-q i { color: var(--primary); transition: transform 0.3s ease; font-size: 0.9rem; }
    .faq-item .faq-q.open i { transform: rotate(180deg); }
    .faq-item .faq-a {
        padding: 0 24px 18px; font-size: 0.95rem; color: var(--text-light);
        display: none; line-height: 1.7;
    }
    .faq-item .faq-a.open { display: block; }

    /* ===== CTA ===== */
    .cta-block {
        text-align: center; padding: 64px 40px;
        background: var(--primary-gradient); border-radius: var(--radius-lg);
        position: relative; overflow: hidden;
    }
    .cta-block::before {
        content: ''; position: absolute; inset: 0;
        background: url('/assets/images/backpic/back-2.png') center/cover no-repeat;
        opacity: 0.1; mix-blend-mode: overlay;
    }
    .cta-block * { position: relative; z-index: 1; }
    .cta-block h2 { color: #fff; font-size: 2rem; margin-bottom: 12px; }
    .cta-block p { color: rgba(255,255,255,0.85); font-size: 1.05rem; max-width: 520px; margin: 0 auto 28px; }
    .cta-block .btn {
        background: #fff; color: var(--primary); font-weight: 700;
        box-shadow: 0 8px 32px rgba(0,0,0,0.15);
    }
    .cta-block .btn:hover { transform: translateY(-3px); box-shadow: 0 12px 40px rgba(0,0,0,0.2); color: var(--primary-dark); }

    /* ===== Footer ===== */
    .app-footer {
        background: var(--bg-dark); color: rgba(255,255,255,0.7); padding: 48px 0 32px;
        margin-top: auto;
    }
    .app-footer .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; }
    .app-footer .footer-brand .brand-text { font-size: 1.1rem; font-weight: 700; color: #fff; margin-bottom: 8px; }
    .app-footer .footer-brand p { font-size: 0.85rem; color: rgba(255,255,255,0.5); max-width: 300px; }
    .app-footer h4 { color: #fff; font-size: 0.95rem; margin-bottom: 16px; font-weight: 600; }
    .app-footer ul li { margin-bottom: 10px; }
    .app-footer ul li a { font-size: 0.85rem; color: rgba(255,255,255,0.6); transition: var(--transition); }
    .app-footer ul li a:hover { color: var(--primary); padding-left: 4px; }
    .app-footer .footer-bottom {
        border-top: 1px solid rgba(255,255,255,0.08);
        padding-top: 24px; margin-top: 40px;
        text-align: center; font-size: 0.8rem; color: rgba(255,255,255,0.4);
    }

    /* ===== Responsive ===== */
    @media (max-width: 1024px) {
        .card-grid-4 { grid-template-columns: repeat(2, 1fr); }
        .steps-grid { grid-template-columns: repeat(2, 1fr); }
        .steps-grid::before { display: none; }
        .app-footer .footer-grid { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
        :root { --nav-width: 0px; }
        .app-nav { transform: translateX(-100%); }
        .app-nav.open { transform: translateX(0); box-shadow: 4px 0 40px rgba(0,0,0,0.3); }
        .app-main { margin-left: 0; }
        .mobile-header { display: flex; }
        .nav-overlay.open { display: block; }
        .hero { padding: 60px 0 50px; }
        .hero h1 { font-size: 2.25rem; }
        .hero p { font-size: 1rem; }
        .hero .hero-stats { gap: 24px; }
        .hero .hero-stats .stat-num { font-size: 1.75rem; }
        .features-grid { grid-template-columns: 1fr; }
        .card-grid-3 { grid-template-columns: 1fr; }
        .card-grid-2 { grid-template-columns: 1fr; }
        .stats-grid { grid-template-columns: repeat(2, 1fr); }
        .steps-grid { grid-template-columns: 1fr; }
        .section { padding: 50px 0; }
        .section-title { margin-bottom: 32px; }
        h1 { font-size: 2rem; }
        h2 { font-size: 1.625rem; }
        .app-footer .footer-grid { grid-template-columns: 1fr; text-align: center; }
        .app-footer .footer-brand p { max-width: 100%; }
        .cta-block { padding: 40px 24px; }
        .cta-block h2 { font-size: 1.5rem; }
    }

    @media (max-width: 520px) {
        .container { padding: 0 16px; }
        .hero h1 { font-size: 1.75rem; }
        .hero .hero-actions .btn { padding: 12px 24px; font-size: 0.95rem; width: 100%; }
        .hero .hero-stats { flex-direction: column; gap: 16px; }
        .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
        .stat-card { padding: 24px 12px; }
        .stat-card .stat-number { font-size: 1.75rem; }
        .news-item { flex-wrap: wrap; gap: 8px; }
        .news-item .news-date { width: 100%; text-align: left; }
        .feature-card { padding: 24px 16px; }
        .app-nav { width: 280px; }
    }

    /* ===== Utilities ===== */
    .text-center { text-align: center; }
    .mt-1 { margin-top: 1rem; }
    .mt-2 { margin-top: 2rem; }
    .mb-1 { margin-bottom: 1rem; }
    .mb-2 { margin-bottom: 2rem; }
    .gap-1 { gap: 1rem; }
    .flex-center { display: flex; align-items: center; justify-content: center; }
    .d-none { display: none; }
    @media (max-width: 768px) {
        .d-mobile-none { display: none; }
    }

    /* ===== Category Intro ===== */
    .cat-intro {
        display: flex; align-items: center; gap: 32px;
        background: var(--bg-alt); border-radius: var(--radius);
        padding: 32px; border: 1px solid var(--border);
    }
    .cat-intro .cat-intro-img { width: 200px; height: 160px; border-radius: var(--radius-sm); object-fit: cover; flex-shrink: 0; }
    .cat-intro .cat-intro-text h3 { font-size: 1.25rem; margin-bottom: 8px; }
    .cat-intro .cat-intro-text p { font-size: 0.9rem; color: var(--text-light); margin-bottom: 0; }
    @media (max-width: 768px) {
        .cat-intro { flex-direction: column; padding: 20px; }
        .cat-intro .cat-intro-img { width: 100%; height: 180px; }
    }

    /* ===== Breadcrumb ===== */
    .breadcrumb {
        display: flex; align-items: center; gap: 8px; font-size: 0.85rem;
        color: var(--text-light); padding: 16px 0;
    }
    .breadcrumb a { color: var(--text-light); }
    .breadcrumb a:hover { color: var(--primary); }
    .breadcrumb .sep { color: var(--border); }

    /* ===== Article Detail ===== */
    .article-header { margin-bottom: 32px; }
    .article-header h1 { font-size: 2.25rem; font-weight: 800; line-height: 1.3; margin-bottom: 16px; }
    .article-header .article-meta {
        display: flex; align-items: center; gap: 20px; flex-wrap: wrap;
        font-size: 0.9rem; color: var(--text-light);
    }
    .article-header .article-meta i { margin-right: 4px; }
    .article-body { font-size: 1.05rem; line-height: 1.8; color: var(--text); }
    .article-body p { margin-bottom: 1.2rem; color: var(--text); }
    .article-body img { border-radius: var(--radius-sm); margin: 24px 0; }
    .article-not-found { text-align: center; padding: 80px 20px; }
    .article-not-found h2 { font-size: 2rem; margin-bottom: 16px; }
    .article-not-found p { color: var(--text-light); margin-bottom: 24px; }

    @media (max-width: 768px) {
        .article-header h1 { font-size: 1.625rem; }
        .article-body { font-size: 0.95rem; }
    }

    /* ===== Category Page Specific ===== */
    .category-hero {
        padding: 60px 0; background: var(--bg-dark);
        background-image: url('/assets/images/backpic/back-3.png');
        background-size: cover; background-position: center; background-blend-mode: overlay;
        position: relative;
    }
    .category-hero::before {
        content: ''; position: absolute; inset: 0;
        background: linear-gradient(135deg, rgba(30,42,74,0.9) 0%, rgba(30,42,74,0.6) 100%);
        z-index: 1;
    }
    .category-hero .container { position: relative; z-index: 2; text-align: center; }
    .category-hero h1 { color: #fff; font-size: 2.5rem; margin-bottom: 12px; }
    .category-hero p { color: rgba(255,255,255,0.7); font-size: 1.05rem; max-width: 560px; margin: 0 auto; }

    @media (max-width: 768px) {
        .category-hero h1 { font-size: 1.75rem; }
        .category-hero { padding: 40px 0; }
    }

/* roulang page: article */
/* ===== 设计变量 ===== */
        :root {
            --primary: #1a1a2e;
            --primary-light: #16213e;
            --primary-dark: #0f0f1a;
            --accent: #e94560;
            --accent-light: #ff6b81;
            --accent-dark: #c23152;
            --gold: #f5a623;
            --gold-light: #ffd700;
            --bg-body: #f8f9fc;
            --bg-card: #ffffff;
            --bg-dark: #1a1a2e;
            --bg-section: #f0f2f8;
            --text-primary: #1a1a2e;
            --text-secondary: #4a4a6a;
            --text-muted: #8888a0;
            --text-light: #ffffff;
            --border-color: #e8e8f0;
            --border-light: #f0f0f8;
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 20px;
            --radius-xl: 28px;
            --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
            --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
            --shadow-lg: 0 20px 60px rgba(0,0,0,0.12);
            --shadow-glow: 0 0 40px rgba(233,69,96,0.15);
            --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
            --sidebar-width: 240px;
            --sidebar-collapsed: 72px;
            --header-height: 0px;
            --max-width: 1280px;
        }

        /* ===== 基础重置 ===== */
        *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
        html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
        body {
            font-family: var(--font-sans);
            background: var(--bg-body);
            color: var(--text-primary);
            line-height: 1.7;
            font-size: 16px;
            min-height: 100vh;
            display: flex;
        }
        img { max-width: 100%; height: auto; display: block; border-radius: var(--radius-sm); }
        a { color: var(--accent); text-decoration: none; transition: var(--transition); }
        a:hover { color: var(--accent-light); }
        ul, ol { list-style: none; }
        button, input, textarea { font-family: inherit; font-size: inherit; outline: none; border: none; }
        button { cursor: pointer; background: none; }
        h1, h2, h3, h4, h5, h6 { line-height: 1.3; font-weight: 700; color: var(--text-primary); }

        /* ===== 左侧导航 (App Shell) ===== */
        .app-nav {
            position: fixed;
            top: 0;
            left: 0;
            width: var(--sidebar-width);
            height: 100vh;
            background: var(--primary);
            color: var(--text-light);
            display: flex;
            flex-direction: column;
            z-index: 1000;
            transition: var(--transition);
            box-shadow: 2px 0 30px rgba(0,0,0,0.2);
            overflow-y: auto;
            overflow-x: hidden;
        }
        .app-nav::-webkit-scrollbar { width: 4px; }
        .app-nav::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.15); border-radius: 4px; }
        .nav-brand {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 28px 20px 24px;
            border-bottom: 1px solid rgba(255,255,255,0.06);
            flex-shrink: 0;
        }
        .brand-icon {
            width: 42px;
            height: 42px;
            background: linear-gradient(135deg, var(--accent), var(--gold));
            border-radius: var(--radius-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 20px;
            color: #fff;
            flex-shrink: 0;
            box-shadow: 0 4px 15px rgba(233,69,96,0.3);
        }
        .brand-text {
            font-size: 18px;
            font-weight: 700;
            letter-spacing: 0.5px;
            background: linear-gradient(135deg, #fff, #e0e0f0);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            line-height: 1.3;
        }
        .nav-menu {
            flex: 1;
            padding: 16px 12px;
            display: flex;
            flex-direction: column;
            gap: 4px;
        }
        .nav-item {
            display: flex;
            align-items: center;
            gap: 14px;
            padding: 13px 16px;
            border-radius: var(--radius-sm);
            color: rgba(255,255,255,0.7);
            font-size: 15px;
            font-weight: 500;
            transition: var(--transition);
            position: relative;
        }
        .nav-item i { width: 20px; text-align: center; font-size: 16px; flex-shrink: 0; }
        .nav-item:hover {
            background: rgba(255,255,255,0.08);
            color: #fff;
            transform: translateX(4px);
        }
        .nav-item.active {
            background: linear-gradient(135deg, rgba(233,69,96,0.25), rgba(245,166,35,0.15));
            color: #fff;
            box-shadow: inset 0 0 0 1px rgba(233,69,96,0.2);
        }
        .nav-item.active::before {
            content: '';
            position: absolute;
            left: 0;
            top: 50%;
            transform: translateY(-50%);
            width: 3px;
            height: 24px;
            background: var(--accent);
            border-radius: 0 4px 4px 0;
        }
        .nav-footer {
            padding: 20px;
            border-top: 1px solid rgba(255,255,255,0.06);
            font-size: 12px;
            color: rgba(255,255,255,0.35);
            text-align: center;
            flex-shrink: 0;
            letter-spacing: 0.3px;
        }

        /* ===== 主内容区 ===== */
        .main-content {
            margin-left: var(--sidebar-width);
            flex: 1;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            transition: var(--transition);
        }

        /* ===== 移动端菜单按钮 ===== */
        .mobile-toggle {
            display: none;
            position: fixed;
            top: 16px;
            left: 16px;
            z-index: 1100;
            width: 44px;
            height: 44px;
            background: var(--primary);
            border-radius: var(--radius-sm);
            color: #fff;
            font-size: 20px;
            align-items: center;
            justify-content: center;
            box-shadow: var(--shadow-md);
            border: 1px solid rgba(255,255,255,0.1);
            cursor: pointer;
            transition: var(--transition);
        }
        .mobile-toggle:hover { background: var(--primary-light); transform: scale(1.05); }
        .mobile-overlay {
            display: none;
            position: fixed;
            top: 0; left: 0; right: 0; bottom: 0;
            background: rgba(0,0,0,0.5);
            z-index: 999;
            backdrop-filter: blur(4px);
            -webkit-backdrop-filter: blur(4px);
        }

        /* ===== Container ===== */
        .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 32px;
            width: 100%;
        }

        /* ===== 文章详情页 ===== */
        .article-page {
            flex: 1;
            padding: 40px 0 60px;
        }
        .article-header {
            margin-bottom: 40px;
        }
        .article-breadcrumb {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 14px;
            color: var(--text-muted);
            margin-bottom: 20px;
            flex-wrap: wrap;
        }
        .article-breadcrumb a { color: var(--text-muted); }
        .article-breadcrumb a:hover { color: var(--accent); }
        .article-breadcrumb .sep { color: var(--border-color); }
        .article-category {
            display: inline-block;
            padding: 4px 16px;
            background: linear-gradient(135deg, rgba(233,69,96,0.12), rgba(245,166,35,0.08));
            color: var(--accent);
            border-radius: 20px;
            font-size: 13px;
            font-weight: 600;
            margin-bottom: 16px;
            border: 1px solid rgba(233,69,96,0.15);
        }
        .article-title {
            font-size: 32px;
            font-weight: 800;
            line-height: 1.3;
            color: var(--text-primary);
            margin-bottom: 16px;
            letter-spacing: -0.3px;
        }
        .article-meta {
            display: flex;
            align-items: center;
            gap: 20px;
            flex-wrap: wrap;
            color: var(--text-muted);
            font-size: 14px;
            padding-bottom: 24px;
            border-bottom: 1px solid var(--border-color);
        }
        .article-meta i { margin-right: 6px; color: var(--accent); }
        .article-meta span { display: flex; align-items: center; }
        .article-featured-image {
            margin: 32px 0;
            border-radius: var(--radius-md);
            overflow: hidden;
            box-shadow: var(--shadow-md);
            max-height: 500px;
            object-fit: cover;
            width: 100%;
            background: var(--border-light);
        }
        .article-body {
            font-size: 16px;
            line-height: 1.9;
            color: var(--text-secondary);
        }
        .article-body p { margin-bottom: 1.2em; }
        .article-body h2 { font-size: 24px; margin: 36px 0 16px; color: var(--text-primary); }
        .article-body h3 { font-size: 20px; margin: 28px 0 12px; color: var(--text-primary); }
        .article-body ul, .article-body ol { margin: 16px 0; padding-left: 24px; }
        .article-body li { margin-bottom: 8px; list-style: disc; }
        .article-body ol li { list-style: decimal; }
        .article-body blockquote {
            border-left: 4px solid var(--accent);
            background: rgba(233,69,96,0.05);
            padding: 16px 24px;
            margin: 24px 0;
            border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
            color: var(--text-secondary);
            font-style: italic;
        }
        .article-body a { color: var(--accent); text-decoration: underline; }
        .article-body img { margin: 24px 0; border-radius: var(--radius-sm); box-shadow: var(--shadow-sm); }
        .article-body table { width: 100%; border-collapse: collapse; margin: 24px 0; }
        .article-body th, .article-body td { padding: 12px 16px; border: 1px solid var(--border-color); text-align: left; }
        .article-body th { background: var(--bg-section); font-weight: 600; }
        .article-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 40px;
            padding-top: 24px;
            border-top: 1px solid var(--border-color);
        }
        .article-tag {
            padding: 6px 16px;
            background: var(--bg-section);
            border-radius: 20px;
            font-size: 13px;
            color: var(--text-secondary);
            border: 1px solid var(--border-color);
            transition: var(--transition);
        }
        .article-tag:hover { background: var(--accent); color: #fff; border-color: var(--accent); }
        .article-nav {
            display: flex;
            justify-content: space-between;
            margin-top: 48px;
            padding-top: 24px;
            border-top: 1px solid var(--border-color);
            gap: 16px;
            flex-wrap: wrap;
        }
        .article-nav a {
            padding: 12px 24px;
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-sm);
            color: var(--text-primary);
            font-size: 14px;
            transition: var(--transition);
            display: flex;
            align-items: center;
            gap: 8px;
            box-shadow: var(--shadow-sm);
            flex: 1;
            max-width: 48%;
        }
        .article-nav a:hover {
            border-color: var(--accent);
            color: var(--accent);
            box-shadow: var(--shadow-md);
            transform: translateY(-2px);
        }
        .article-nav a:only-child { max-width: 100%; justify-content: center; }

        /* ===== 404 / 未找到 ===== */
        .not-found {
            text-align: center;
            padding: 80px 20px;
        }
        .not-found-icon {
            font-size: 64px;
            color: var(--accent);
            margin-bottom: 24px;
            opacity: 0.6;
        }
        .not-found h2 { font-size: 28px; margin-bottom: 12px; }
        .not-found p { color: var(--text-muted); margin-bottom: 24px; }
        .btn-back {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            padding: 12px 32px;
            background: var(--accent);
            color: #fff;
            border-radius: var(--radius-sm);
            font-weight: 600;
            transition: var(--transition);
        }
        .btn-back:hover { background: var(--accent-dark); color: #fff; transform: translateY(-2px); box-shadow: var(--shadow-md); }

        /* ===== Footer ===== */
        .app-footer {
            background: var(--primary);
            color: rgba(255,255,255,0.8);
            padding: 48px 0 32px;
            margin-top: auto;
        }
        .app-footer .container { padding: 0 32px; }
        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 40px;
            margin-bottom: 32px;
        }
        .footer-brand .brand-text {
            font-size: 20px;
            font-weight: 700;
            margin-bottom: 12px;
            display: block;
            -webkit-text-fill-color: #fff;
            background: none;
        }
        .footer-brand p { font-size: 14px; color: rgba(255,255,255,0.55); line-height: 1.7; max-width: 340px; }
        .app-footer h4 { color: #fff; font-size: 15px; font-weight: 600; margin-bottom: 16px; }
        .app-footer ul li { margin-bottom: 10px; }
        .app-footer ul li a { color: rgba(255,255,255,0.55); font-size: 14px; transition: var(--transition); }
        .app-footer ul li a:hover { color: var(--accent-light); padding-left: 4px; }
        .footer-bottom {
            border-top: 1px solid rgba(255,255,255,0.06);
            padding-top: 24px;
            text-align: center;
            font-size: 13px;
            color: rgba(255,255,255,0.35);
            letter-spacing: 0.3px;
        }

        /* ===== 响应式 ===== */
        @media (max-width: 1024px) {
            .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
            .footer-brand { grid-column: 1 / -1; }
        }
        @media (max-width: 768px) {
            :root { --sidebar-width: 0px; }
            .app-nav {
                transform: translateX(-100%);
                width: 260px;
                box-shadow: none;
            }
            .app-nav.open { transform: translateX(0); box-shadow: 4px 0 40px rgba(0,0,0,0.3); }
            .mobile-toggle { display: flex; }
            .mobile-overlay.open { display: block; }
            .main-content { margin-left: 0; padding-top: 72px; }
            .container { padding: 0 20px; }
            .article-title { font-size: 24px; }
            .article-meta { gap: 12px; font-size: 13px; }
            .article-body { font-size: 15px; }
            .article-nav a { max-width: 100%; flex: 1 1 100%; }
            .footer-grid { grid-template-columns: 1fr; gap: 24px; }
            .app-footer .container { padding: 0 20px; }
            .article-page { padding: 24px 0 40px; }
        }
        @media (max-width: 520px) {
            .container { padding: 0 16px; }
            .article-title { font-size: 20px; }
            .article-meta { flex-direction: column; gap: 6px; align-items: flex-start; }
            .article-body { font-size: 14px; }
            .article-body h2 { font-size: 20px; }
            .article-body h3 { font-size: 17px; }
            .article-nav { flex-direction: column; }
            .article-nav a { max-width: 100%; }
            .not-found { padding: 48px 16px; }
            .not-found-icon { font-size: 48px; }
        }

/* roulang page: category1 */
/* ===== DESIGN VARIABLES ===== */
        :root {
            --primary: #e63946;
            --primary-dark: #c1121f;
            --primary-light: #fae0e3;
            --secondary: #1d3557;
            --secondary-light: #2a4a7f;
            --accent: #f4a261;
            --background: #f8f9fa;
            --surface: #ffffff;
            --text: #1a1a2e;
            --text-weak: #6c757d;
            --text-inverse: #ffffff;
            --border: #e0e0e0;
            --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
            --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.10);
            --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.15);
            --radius-sm: 8px;
            --radius-md: 16px;
            --radius-lg: 24px;
            --radius-xl: 32px;
            --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
            --nav-width: 240px;
            --header-height: 0px;
            --spacing-section: 80px;
            --max-width: 1200px;
        }

        /* ===== RESET & BASE ===== */
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            border: 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);
            background: var(--background);
            display: flex;
            min-height: 100vh;
        }

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

        img {
            max-width: 100%;
            height: auto;
            display: block;
            border-radius: var(--radius-sm);
        }

        ul,
        ol {
            list-style: none;
            padding: 0;
        }

        button,
        input,
        textarea {
            font-family: inherit;
            font-size: 1rem;
            outline: none;
            transition: all var(--transition);
        }

        button {
            cursor: pointer;
            background: none;
            border: none;
        }

        /* ===== CONTAINER ===== */
        .container {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ===== APP SHELL NAV (LEFT) ===== */
        .app-nav {
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            width: var(--nav-width);
            background: var(--surface);
            border-right: 1px solid var(--border);
            display: flex;
            flex-direction: column;
            padding: 28px 0 20px;
            z-index: 1000;
            transition: transform var(--transition);
            overflow-y: auto;
        }

        .nav-brand {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 0 24px 24px;
            border-bottom: 1px solid var(--border);
            margin-bottom: 16px;
        }

        .brand-icon {
            width: 42px;
            height: 42px;
            background: var(--primary);
            color: #fff;
            border-radius: var(--radius-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
            flex-shrink: 0;
            box-shadow: 0 4px 12px rgba(230, 57, 70, 0.3);
        }

        .brand-text {
            font-weight: 700;
            font-size: 1.1rem;
            color: var(--text);
            letter-spacing: -0.01em;
            line-height: 1.3;
        }

        .nav-menu {
            display: flex;
            flex-direction: column;
            gap: 4px;
            padding: 0 12px;
            flex: 1;
        }

        .nav-item {
            display: flex;
            align-items: center;
            gap: 14px;
            padding: 12px 16px;
            border-radius: var(--radius-sm);
            font-weight: 500;
            font-size: 0.95rem;
            color: var(--text-weak);
            transition: all var(--transition);
            position: relative;
        }

        .nav-item i {
            width: 20px;
            text-align: center;
            font-size: 1.05rem;
            flex-shrink: 0;
        }

        .nav-item:hover {
            background: var(--primary-light);
            color: var(--primary);
        }

        .nav-item.active {
            background: var(--primary);
            color: #fff;
            box-shadow: 0 4px 16px rgba(230, 57, 70, 0.3);
        }

        .nav-item.active i {
            color: #fff;
        }

        .nav-footer {
            padding: 16px 24px 0;
            font-size: 0.8rem;
            color: var(--text-weak);
            border-top: 1px solid var(--border);
            margin-top: 12px;
            text-align: center;
        }

        /* ===== MAIN CONTENT AREA ===== */
        .main-content {
            margin-left: var(--nav-width);
            flex: 1;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* ===== HERO / BANNER ===== */
        .category-banner {
            position: relative;
            padding: 80px 0 72px;
            background: var(--secondary);
            background-image: url('/assets/images/backpic/back-2.png');
            background-size: cover;
            background-position: center;
            background-blend-mode: overlay;
            color: var(--text-inverse);
            overflow: hidden;
        }

        .category-banner::before {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(135deg, rgba(29, 53, 87, 0.88) 0%, rgba(230, 57, 70, 0.70) 100%);
            z-index: 1;
        }

        .category-banner .container {
            position: relative;
            z-index: 2;
            text-align: center;
        }

        .category-banner h1 {
            font-size: 2.8rem;
            font-weight: 800;
            letter-spacing: -0.02em;
            margin-bottom: 16px;
            line-height: 1.2;
        }

        .category-banner h1 i {
            margin-right: 12px;
            color: var(--accent);
        }

        .category-banner p {
            font-size: 1.15rem;
            max-width: 680px;
            margin: 0 auto;
            opacity: 0.92;
            line-height: 1.7;
        }

        .banner-meta {
            display: flex;
            justify-content: center;
            gap: 40px;
            margin-top: 28px;
            flex-wrap: wrap;
        }

        .banner-meta span {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 0.95rem;
            background: rgba(255, 255, 255, 0.15);
            backdrop-filter: blur(6px);
            padding: 8px 20px;
            border-radius: 40px;
        }

        .banner-meta i {
            color: var(--accent);
        }

        /* ===== SECTION COMMON ===== */
        .section {
            padding: var(--spacing-section) 0;
        }

        .section-alt {
            background: var(--surface);
        }

        .section-header {
            text-align: center;
            margin-bottom: 48px;
        }

        .section-header h2 {
            font-size: 2rem;
            font-weight: 700;
            color: var(--text);
            letter-spacing: -0.01em;
            margin-bottom: 12px;
        }

        .section-header h2 i {
            color: var(--primary);
            margin-right: 8px;
        }

        .section-header p {
            color: var(--text-weak);
            font-size: 1.05rem;
            max-width: 560px;
            margin: 0 auto;
        }

        .divider {
            width: 60px;
            height: 4px;
            background: var(--primary);
            border-radius: 4px;
            margin: 12px auto 0;
        }

        /* ===== DOWNLOAD STEPS ===== */
        .steps-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 30px;
        }

        .step-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 36px 28px 32px;
            text-align: center;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border);
            transition: all var(--transition);
            position: relative;
        }

        .step-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-md);
            border-color: var(--primary);
        }

        .step-number {
            width: 52px;
            height: 52px;
            background: var(--primary);
            color: #fff;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.4rem;
            font-weight: 700;
            margin: 0 auto 18px;
            box-shadow: 0 6px 20px rgba(230, 57, 70, 0.25);
        }

        .step-card h3 {
            font-size: 1.2rem;
            font-weight: 600;
            margin-bottom: 10px;
            color: var(--text);
        }

        .step-card p {
            color: var(--text-weak);
            font-size: 0.95rem;
            line-height: 1.6;
        }

        /* ===== PLATFORM CARDS ===== */
        .platform-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 30px;
        }

        .platform-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 36px 32px;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border);
            transition: all var(--transition);
            display: flex;
            align-items: flex-start;
            gap: 24px;
        }

        .platform-card:hover {
            box-shadow: var(--shadow-md);
            transform: translateY(-4px);
        }

        .platform-icon {
            width: 64px;
            height: 64px;
            border-radius: var(--radius-sm);
            background: var(--primary-light);
            color: var(--primary);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.8rem;
            flex-shrink: 0;
        }

        .platform-card.android .platform-icon {
            background: #e8f5e9;
            color: #2e7d32;
        }

        .platform-card.ios .platform-icon {
            background: #e3f2fd;
            color: #1565c0;
        }

        .platform-info {
            flex: 1;
        }

        .platform-info h3 {
            font-size: 1.3rem;
            font-weight: 600;
            margin-bottom: 8px;
        }

        .platform-info p {
            color: var(--text-weak);
            font-size: 0.95rem;
            margin-bottom: 16px;
            line-height: 1.6;
        }

        .platform-info ul {
            display: flex;
            flex-wrap: wrap;
            gap: 8px 20px;
            margin-bottom: 18px;
        }

        .platform-info ul li {
            font-size: 0.9rem;
            color: var(--text);
            display: flex;
            align-items: center;
            gap: 6px;
        }

        .platform-info ul li i {
            color: var(--primary);
            font-size: 0.8rem;
        }

        .btn-download {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 12px 32px;
            background: var(--primary);
            color: #fff;
            border-radius: 40px;
            font-weight: 600;
            font-size: 1rem;
            transition: all var(--transition);
            box-shadow: 0 4px 16px rgba(230, 57, 70, 0.25);
        }

        .btn-download:hover {
            background: var(--primary-dark);
            transform: translateY(-2px);
            box-shadow: 0 8px 28px rgba(230, 57, 70, 0.35);
            color: #fff;
        }

        .btn-download i {
            font-size: 1.1rem;
        }

        .btn-outline {
            background: transparent;
            color: var(--primary);
            border: 2px solid var(--primary);
            box-shadow: none;
        }

        .btn-outline:hover {
            background: var(--primary);
            color: #fff;
            border-color: var(--primary);
        }

        /* ===== VERSION INFO ===== */
        .version-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 40px 36px;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border);
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 24px;
        }

        .version-item {
            text-align: center;
            padding: 16px 12px;
            border-right: 1px solid var(--border);
        }

        .version-item:last-child {
            border-right: none;
        }

        .version-item .label {
            font-size: 0.85rem;
            color: var(--text-weak);
            text-transform: uppercase;
            letter-spacing: 0.04em;
            margin-bottom: 6px;
        }

        .version-item .value {
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--text);
        }

        .version-item .value i {
            color: var(--primary);
            margin-right: 6px;
        }

        /* ===== FAQ ===== */
        .faq-list {
            max-width: 780px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .faq-item {
            background: var(--surface);
            border-radius: var(--radius-sm);
            border: 1px solid var(--border);
            overflow: hidden;
            transition: all var(--transition);
        }

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

        .faq-question {
            padding: 20px 24px;
            font-weight: 600;
            font-size: 1.05rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            cursor: pointer;
            transition: background var(--transition);
            gap: 16px;
        }

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

        .faq-question i {
            color: var(--primary);
            transition: transform var(--transition);
            flex-shrink: 0;
        }

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

        .faq-answer {
            padding: 0 24px 20px;
            color: var(--text-weak);
            font-size: 0.95rem;
            line-height: 1.7;
            display: none;
        }

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

        /* ===== CTA ===== */
        .cta-section {
            background: var(--secondary);
            background-image: url('/assets/images/backpic/back-3.png');
            background-size: cover;
            background-position: center;
            background-blend-mode: overlay;
            color: var(--text-inverse);
            text-align: center;
            padding: 72px 0;
            position: relative;
        }

        .cta-section::before {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(135deg, rgba(230, 57, 70, 0.85) 0%, rgba(29, 53, 87, 0.88) 100%);
            z-index: 1;
        }

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

        .cta-section h2 {
            font-size: 2.2rem;
            font-weight: 700;
            margin-bottom: 16px;
        }

        .cta-section p {
            font-size: 1.1rem;
            opacity: 0.92;
            margin-bottom: 32px;
            max-width: 560px;
            margin-left: auto;
            margin-right: auto;
        }

        .cta-buttons {
            display: flex;
            justify-content: center;
            gap: 20px;
            flex-wrap: wrap;
        }

        .btn-cta {
            display: inline-flex;
            align-items: center;
            gap: 12px;
            padding: 16px 40px;
            border-radius: 40px;
            font-weight: 700;
            font-size: 1.1rem;
            transition: all var(--transition);
        }

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

        .btn-cta-primary:hover {
            background: var(--accent);
            color: #fff;
            transform: translateY(-3px);
            box-shadow: 0 12px 32px rgba(0, 0, 0, 0.2);
        }

        .btn-cta-secondary {
            background: transparent;
            color: #fff;
            border: 2px solid rgba(255, 255, 255, 0.5);
        }

        .btn-cta-secondary:hover {
            border-color: #fff;
            background: rgba(255, 255, 255, 0.1);
            transform: translateY(-3px);
        }

        /* ===== FOOTER ===== */
        .app-footer {
            background: var(--secondary);
            color: rgba(255, 255, 255, 0.85);
            padding: 56px 0 32px;
            margin-top: auto;
        }

        .app-footer .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 40px;
            margin-bottom: 36px;
        }

        .footer-brand .brand-text {
            font-size: 1.2rem;
            font-weight: 700;
            color: #fff;
            margin-bottom: 12px;
        }

        .footer-brand p {
            font-size: 0.92rem;
            line-height: 1.7;
            opacity: 0.8;
        }

        .app-footer h4 {
            color: #fff;
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 16px;
        }

        .app-footer ul li {
            margin-bottom: 10px;
        }

        .app-footer ul li a {
            color: rgba(255, 255, 255, 0.7);
            font-size: 0.92rem;
            transition: color var(--transition);
        }

        .app-footer ul li a:hover {
            color: var(--accent);
        }

        .footer-bottom {
            border-top: 1px solid rgba(255, 255, 255, 0.12);
            padding-top: 24px;
            text-align: center;
            font-size: 0.85rem;
            opacity: 0.7;
        }

        /* ===== MOBILE NAV TOGGLE ===== */
        .nav-toggle {
            display: none;
            position: fixed;
            top: 16px;
            left: 16px;
            z-index: 1100;
            width: 44px;
            height: 44px;
            background: var(--surface);
            border-radius: var(--radius-sm);
            box-shadow: var(--shadow-md);
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
            color: var(--text);
            border: none;
            cursor: pointer;
            transition: all var(--transition);
        }

        .nav-toggle:hover {
            background: var(--primary);
            color: #fff;
        }

        .overlay {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(0, 0, 0, 0.5);
            z-index: 999;
            opacity: 0;
            transition: opacity var(--transition);
        }

        .overlay.show {
            opacity: 1;
        }

        /* ===== RESPONSIVE ===== */
        @media (max-width: 1024px) {
            :root {
                --nav-width: 220px;
                --spacing-section: 60px;
            }

            .category-banner h1 {
                font-size: 2.2rem;
            }

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

            .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 32px;
            }
        }

        @media (max-width: 768px) {
            .nav-toggle {
                display: flex;
            }

            .app-nav {
                transform: translateX(-100%);
                width: 280px;
                box-shadow: var(--shadow-lg);
            }

            .app-nav.open {
                transform: translateX(0);
            }

            .overlay.show {
                display: block;
            }

            .main-content {
                margin-left: 0;
            }

            .category-banner {
                padding: 60px 0 48px;
            }

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

            .category-banner p {
                font-size: 1rem;
            }

            .banner-meta {
                gap: 16px;
            }

            .banner-meta span {
                font-size: 0.85rem;
                padding: 6px 16px;
            }

            :root {
                --spacing-section: 48px;
            }

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

            .steps-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }

            .platform-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }

            .platform-card {
                flex-direction: column;
                align-items: center;
                text-align: center;
                padding: 28px 20px;
            }

            .platform-info ul {
                justify-content: center;
            }

            .version-card {
                grid-template-columns: 1fr 1fr;
                gap: 16px;
                padding: 24px 16px;
            }

            .version-item {
                border-right: none;
                border-bottom: 1px solid var(--border);
                padding: 12px 0;
            }

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

            .footer-grid {
                grid-template-columns: 1fr;
                gap: 24px;
                text-align: center;
            }

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

            .cta-buttons {
                flex-direction: column;
                align-items: center;
            }

            .btn-cta {
                width: 100%;
                max-width: 320px;
                justify-content: center;
            }
        }

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

            .category-banner {
                padding: 48px 0 36px;
            }

            .section-header h2 {
                font-size: 1.4rem;
            }

            .step-card {
                padding: 24px 18px;
            }

            .platform-card {
                padding: 20px 16px;
            }

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

            .faq-question {
                padding: 16px 18px;
                font-size: 0.95rem;
            }

            .faq-answer {
                padding: 0 18px 16px;
            }

            .btn-download {
                padding: 10px 24px;
                font-size: 0.95rem;
            }
        }

        /* ===== SAFE AREA & SCROLLBAR ===== */
        .app-nav::-webkit-scrollbar {
            width: 4px;
        }

        .app-nav::-webkit-scrollbar-track {
            background: transparent;
        }

        .app-nav::-webkit-scrollbar-thumb {
            background: var(--border);
            border-radius: 10px;
        }

        /* ===== UTILITY ===== */
        .text-center {
            text-align: center;
        }

        .mt-16 {
            margin-top: 16px;
        }

        .mb-16 {
            margin-bottom: 16px;
        }

        .gap-8 {
            gap: 8px;
        }

        .flex-center {
            display: flex;
            align-items: center;
            justify-content: center;
        }

        /* ===== TAG / BADGE ===== */
        .badge {
            display: inline-block;
            padding: 4px 14px;
            border-radius: 40px;
            font-size: 0.8rem;
            font-weight: 600;
            background: var(--primary-light);
            color: var(--primary);
        }

        .badge-green {
            background: #e8f5e9;
            color: #2e7d32;
        }

        .badge-blue {
            background: #e3f2fd;
            color: #1565c0;
        }