:root {
            --bg-primary: #080c1a;
            --bg-secondary: #0d1330;
            --bg-card: rgba(255, 255, 255, 0.04);
            --bg-card-hover: rgba(255, 255, 255, 0.07);
            --border-glass: rgba(255, 255, 255, 0.08);
            --border-active: rgba(124, 58, 237, 0.25);
            --text-primary: #ffffff;
            --text-secondary: rgba(255, 255, 255, 0.75);
            --text-muted: rgba(255, 255, 255, 0.45);
            --accent-purple: #7c3aed;
            --accent-blue: #3b82f6;
            --accent-cyan: #06b6d4;
            --accent-pink: #ec4899;
            --accent-green: #10b981;
            --accent-amber: #f59e0b;
            --gradient-main: linear-gradient(135deg, #7c3aed, #3b82f6);
            --gradient-glow: linear-gradient(135deg, rgba(124, 58, 237, 0.3), rgba(59, 130, 246, 0.3));
            --shadow-glow: 0 0 60px rgba(124, 58, 237, 0.15), 0 0 120px rgba(59, 130, 246, 0.08);
            --shadow-card: 0 0 40px rgba(124, 58, 237, 0.08);
            --radius-sm: 10px;
            --radius-md: 16px;
            --radius-lg: 24px;
            --radius-xl: 32px;
            --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            --transition-fast: 0.2s ease;
            --transition-smooth: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
            scroll-padding-top: 100px;
        }
        body {
            font-family: var(--font-family);
            background: var(--bg-primary);
            color: var(--text-primary);
            line-height: 1.6;
            overflow-x: hidden;
            min-height: 100vh;
            -webkit-font-smoothing: antialiased;
        }
        ::-webkit-scrollbar {
            width: 5px;
        }
        ::-webkit-scrollbar-track {
            background: var(--bg-primary);
        }
        ::-webkit-scrollbar-thumb {
            background: var(--accent-purple);
            border-radius: 10px;
        }
        ::-webkit-scrollbar-thumb:hover {
            background: #9b6dff;
        }

        canvas#particles {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 0;
            pointer-events: none;
        }
        .app {
            position: relative;
            z-index: 1;
        }
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ===== HEADER (与首页保持一致) ===== */
        header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 100;
            padding: 14px 0;
            background: rgba(8, 12, 26, 0.72);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-bottom: 1px solid var(--border-glass);
            transition: all var(--transition-smooth);
        }
        header.scrolled {
            background: rgba(8, 12, 26, 0.94);
            box-shadow: 0 4px 40px rgba(0, 0, 0, 0.5);
            padding: 10px 0;
        }
        .header-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 12px;
        }
        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            font-weight: 800;
            font-size: 21px;
            color: var(--text-primary);
            letter-spacing: -0.5px;
            flex-shrink: 0;
        }
        .logo:hover {
            opacity: 0.85;
        }
        .logo-icon {
            width: 34px;
            height: 34px;
            border-radius: 10px;
            background: var(--gradient-main);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 16px;
            font-weight: 900;
            color: #fff;
            box-shadow: 0 0 24px rgba(124, 58, 237, 0.35);
            transition: transform var(--transition-smooth);
            flex-shrink: 0;
        }
        .logo:hover .logo-icon {
            transform: rotate(-6deg) scale(1.06);
        }
        .logo span {
            background: var(--gradient-main);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        nav {
            display: flex;
            align-items: center;
            gap: 4px;
            flex-wrap: wrap;
        }
        nav a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 14px;
            font-weight: 500;
            padding: 8px 16px;
            border-radius: 8px;
            transition: all var(--transition-fast);
            letter-spacing: 0.2px;
            white-space: nowrap;
        }
        nav a:hover {
            color: var(--text-primary);
            background: rgba(255, 255, 255, 0.06);
        }
        nav a.active {
            color: #fff;
            background: rgba(124, 58, 237, 0.2);
            box-shadow: 0 0 20px rgba(124, 58, 237, 0.08);
            position: relative;
        }
        nav a.active::after {
            content: '';
            position: absolute;
            bottom: 4px;
            left: 50%;
            transform: translateX(-50%);
            width: 18px;
            height: 2px;
            border-radius: 2px;
            background: var(--gradient-main);
        }
        .header-actions {
            display: flex;
            align-items: center;
            gap: 10px;
            flex-shrink: 0;
        }
        .btn-download-small {
            padding: 8px 18px;
            border-radius: 8px;
            background: var(--gradient-main);
            color: #fff;
            font-size: 13px;
            font-weight: 600;
            border: none;
            cursor: pointer;
            text-decoration: none;
            transition: all var(--transition-smooth);
            box-shadow: 0 0 28px rgba(124, 58, 237, 0.22);
            display: inline-flex;
            align-items: center;
            gap: 6px;
            white-space: nowrap;
        }
        .btn-download-small:hover {
            transform: translateY(-2px);
            box-shadow: 0 0 44px rgba(124, 58, 237, 0.4);
        }
        .mobile-toggle {
            display: none;
            flex-direction: column;
            gap: 4px;
            background: none;
            border: none;
            cursor: pointer;
            padding: 4px;
            z-index: 101;
        }
        .mobile-toggle span {
            display: block;
            width: 24px;
            height: 2px;
            background: var(--text-primary);
            border-radius: 2px;
            transition: all var(--transition-smooth);
        }
        .mobile-toggle.active span:nth-child(1) {
            transform: rotate(45deg) translate(4px, 4px);
        }
        .mobile-toggle.active span:nth-child(2) {
            opacity: 0;
            transform: scaleX(0);
        }
        .mobile-toggle.active span:nth-child(3) {
            transform: rotate(-45deg) translate(4px, -4px);
        }

        @media (max-width: 820px) {
            .mobile-toggle {
                display: flex;
            }
            nav {
                display: none;
                width: 100%;
                flex-direction: column;
                align-items: stretch;
                padding: 14px 0 6px;
                gap: 2px;
            }
            nav.open {
                display: flex;
            }
            nav a {
                padding: 12px 16px;
                font-size: 15px;
                text-align: center;
            }
            nav a.active::after {
                display: none;
            }
            .header-actions .btn-download-small {
                display: none;
            }
            .header-actions .btn-download-small.mobile-show {
                display: inline-flex;
            }
        }
        @media (min-width: 821px) {
            .header-actions .btn-download-small.mobile-show {
                display: none;
            }
        }

        /* ===== PAGE HERO ===== */
        .page-hero {
            padding: 140px 0 30px;
            position: relative;
            text-align: center;
        }
        .page-hero::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 55%;
            height: 1px;
            background: linear-gradient(90deg, transparent, rgba(124, 58, 237, 0.25), transparent);
            opacity: 0.6;
        }
        .section-label {
            display: inline-block;
            font-size: 11px;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 2.5px;
            color: var(--accent-cyan);
            background: rgba(6, 182, 212, 0.07);
            padding: 4px 14px;
            border-radius: 50px;
            border: 1px solid rgba(6, 182, 212, 0.08);
            margin-bottom: 14px;
        }
        .page-hero h1 {
            font-size: clamp(34px, 5vw, 52px);
            font-weight: 800;
            letter-spacing: -1.2px;
            margin-bottom: 10px;
            line-height: 1.1;
        }
        .page-hero h1 .highlight {
            background: var(--gradient-main);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .page-hero .hero-subtitle {
            font-size: clamp(15px, 1.1vw, 17px);
            color: var(--text-secondary);
            max-width: 640px;
            margin: 0 auto 12px;
            line-height: 1.7;
        }

        /* 搜索框 */
        .faq-search {
            padding: 20px 0 30px;
            text-align: center;
        }
        .faq-search input {
            max-width: 500px;
            width: 100%;
            padding: 14px 24px;
            border-radius: 50px;
            border: 1px solid var(--border-glass);
            background: rgba(255, 255, 255, 0.04);
            color: var(--text-primary);
            font-size: 15px;
            outline: none;
            transition: all var(--transition-smooth);
            backdrop-filter: blur(8px);
            font-family: inherit;
        }
        .faq-search input::placeholder {
            color: var(--text-muted);
        }
        .faq-search input:focus {
            border-color: var(--accent-purple);
            box-shadow: 0 0 30px rgba(124, 58, 237, 0.1);
            background: rgba(255, 255, 255, 0.06);
        }

        /* 通用区块标题 */
        .section-heading {
            text-align: center;
            margin-bottom: 32px;
        }
        .section-heading .section-label {
            margin-bottom: 12px;
        }
        .section-heading h2 {
            font-size: clamp(24px, 3vw, 36px);
            font-weight: 700;
            letter-spacing: -0.8px;
            margin-bottom: 8px;
        }
        .section-heading h2 .highlight {
            background: var(--gradient-main);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .section-heading p {
            color: var(--text-secondary);
            font-size: 14px;
            max-width: 560px;
            margin: 0 auto;
            line-height: 1.7;
        }

        /* ===== 常见错误代码卡片 (创意板块) ===== */
        .error-codes-section {
            padding: 30px 0 60px;
            position: relative;
        }
        .error-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 20px;
            margin-top: 12px;
        }
        @media (max-width: 820px) {
            .error-grid {
                grid-template-columns: 1fr;
                max-width: 400px;
                margin-left: auto;
                margin-right: auto;
            }
        }
        .error-card {
            padding: 24px 20px;
            border-radius: var(--radius-md);
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            text-align: center;
            transition: all var(--transition-smooth);
            cursor: default;
            position: relative;
            overflow: hidden;
        }
        .error-card:hover {
            border-color: rgba(124, 58, 237, 0.2);
            background: var(--bg-card-hover);
            transform: translateY(-4px);
            box-shadow: var(--shadow-card);
        }
        .error-code {
            font-size: 28px;
            font-weight: 800;
            background: var(--gradient-main);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            display: inline-block;
            margin-bottom: 8px;
        }
        .error-card h4 {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 6px;
        }
        .error-card p {
            font-size: 12px;
            color: var(--text-muted);
            line-height: 1.5;
            margin-bottom: 12px;
        }
        .error-card .btn-tip {
            font-size: 12px;
            font-weight: 500;
            color: var(--accent-cyan);
            text-decoration: none;
            transition: color var(--transition-fast);
        }
        .error-card .btn-tip:hover {
            color: #67e8f9;
        }

        /* ===== 自助排查步骤 ===== */
        .troubleshoot-steps {
            padding: 30px 0 60px;
            position: relative;
        }
        .troubleshoot-steps::before {
            content: '';
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 50%;
            height: 1px;
            background: linear-gradient(90deg, transparent, rgba(124, 58, 237, 0.18), transparent);
            pointer-events: none;
        }
        .steps-list {
            max-width: 700px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 16px;
        }
        .step-item {
            display: flex;
            align-items: flex-start;
            gap: 16px;
            padding: 16px 20px;
            border-radius: var(--radius-md);
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            transition: all var(--transition-smooth);
            position: relative;
        }
        .step-item:hover {
            border-color: rgba(124, 58, 237, 0.2);
            background: var(--bg-card-hover);
            transform: translateX(4px);
            box-shadow: var(--shadow-card);
        }
        .step-num {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background: var(--gradient-main);
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 800;
            font-size: 15px;
            color: #fff;
            flex-shrink: 0;
            box-shadow: 0 0 18px rgba(124, 58, 237, 0.25);
        }
        .step-content h5 {
            font-size: 15px;
            font-weight: 600;
            margin-bottom: 2px;
        }
        .step-content p {
            font-size: 12px;
            color: var(--text-muted);
            line-height: 1.6;
        }

        /* ===== 使用建议板块 ===== */
        .tips-section {
            padding: 30px 0 60px;
            position: relative;
        }
        .tips-section::before {
            content: '';
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 50%;
            height: 1px;
            background: linear-gradient(90deg, transparent, rgba(124, 58, 237, 0.18), transparent);
            pointer-events: none;
        }
        .tips-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 20px;
            margin-top: 12px;
        }
        @media (max-width: 640px) {
            .tips-grid {
                grid-template-columns: 1fr;
                max-width: 400px;
                margin-left: auto;
                margin-right: auto;
            }
        }
        .tip-card {
            padding: 22px 20px;
            border-radius: var(--radius-md);
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            display: flex;
            gap: 16px;
            align-items: flex-start;
            transition: all var(--transition-smooth);
            cursor: default;
        }
        .tip-card:hover {
            border-color: rgba(124, 58, 237, 0.18);
            background: var(--bg-card-hover);
            transform: translateY(-3px);
            box-shadow: var(--shadow-card);
        }
        .tip-icon {
            font-size: 28px;
            flex-shrink: 0;
            width: 40px;
            text-align: center;
        }
        .tip-card h4 {
            font-size: 15px;
            font-weight: 600;
            margin-bottom: 4px;
        }
        .tip-card p {
            font-size: 12px;
            color: var(--text-muted);
            line-height: 1.5;
        }

        /* ===== FAQ折叠列表 ===== */
        .faq-section {
            padding: 30px 0 60px;
            position: relative;
        }
        .faq-section::before {
            content: '';
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 50%;
            height: 1px;
            background: linear-gradient(90deg, transparent, rgba(124, 58, 237, 0.18), transparent);
            pointer-events: none;
        }
        .faq-items {
            max-width: 800px;
            margin: 0 auto;
        }
        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            border-radius: 16px;
            margin-bottom: 14px;
            transition: all var(--transition-smooth);
            overflow: hidden;
        }
        .faq-item:hover {
            border-color: rgba(124, 58, 237, 0.2);
            background: var(--bg-card-hover);
        }
        .faq-item summary {
            padding: 18px 24px;
            cursor: pointer;
            font-weight: 600;
            font-size: 15px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            list-style: none;
            transition: background var(--transition-fast);
            user-select: none;
        }
        .faq-item summary::-webkit-details-marker {
            display: none;
        }
        .faq-item summary::after {
            content: '+';
            font-size: 22px;
            font-weight: 300;
            color: var(--text-muted);
            transition: transform var(--transition-fast);
            flex-shrink: 0;
            margin-left: 16px;
        }
        .faq-item[open] summary::after {
            content: '−';
        }
        .faq-item .answer {
            padding: 8px 24px 20px 24px;
            color: var(--text-secondary);
            font-size: 14px;
            line-height: 1.6;
            border-top: 1px solid var(--border-glass);
        }
        .no-result {
            text-align: center;
            padding: 40px 0;
            color: var(--text-muted);
            font-size: 15px;
            display: none;
        }
        .no-result.visible {
            display: block;
        }

        /* ===== 联系客服板块 ===== */
        .contact-section {
            padding: 20px 0 70px;
            text-align: center;
        }
        .contact-wrap {
            display: inline-flex;
            flex-direction: column;
            align-items: center;
            gap: 16px;
            padding: 32px 40px;
            border-radius: var(--radius-lg);
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            backdrop-filter: blur(8px);
            transition: all var(--transition-smooth);
        }
        .contact-wrap:hover {
            border-color: rgba(124, 58, 237, 0.2);
            box-shadow: var(--shadow-glow);
        }
        .contact-wrap p {
            font-size: 14px;
            color: var(--text-secondary);
            max-width: 400px;
        }
        .btn-contact {
            padding: 10px 28px;
            border-radius: 10px;
            background: var(--gradient-main);
            color: #fff;
            font-weight: 600;
            text-decoration: none;
            transition: all var(--transition-smooth);
            box-shadow: 0 0 24px rgba(124, 58, 237, 0.2);
        }
        .btn-contact:hover {
            transform: translateY(-2px);
            box-shadow: 0 0 40px rgba(124, 58, 237, 0.35);
        }

        /* ===== FOOTER ===== */
        footer {
            padding: 36px 0 28px;
            border-top: 1px solid var(--border-glass);
        }
        .footer-inner {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 18px;
        }
        .footer-inner .copy {
            font-size: 12px;
            color: var(--text-muted);
        }
        .footer-inner .footer-links {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }
        .footer-inner .footer-links a {
            color: var(--text-muted);
            text-decoration: none;
            font-size: 12px;
            transition: color var(--transition-fast);
        }
        .footer-inner .footer-links a:hover {
            color: var(--text-primary);
        }
        @media (max-width: 640px) {
            .footer-inner {
                flex-direction: column;
                text-align: center;
            }
            .footer-inner .footer-links {
                justify-content: center;
            }
        }

        /* ===== SCROLL TOP ===== */
        .scroll-top {
            position: fixed;
            bottom: 28px;
            right: 28px;
            width: 42px;
            height: 42px;
            border-radius: 50%;
            background: var(--bg-card);
            border: 1px solid var(--border-glass);
            color: var(--text-secondary);
            font-size: 16px;
            cursor: pointer;
            backdrop-filter: blur(12px);
            transition: all var(--transition-smooth);
            opacity: 0;
            transform: translateY(16px);
            pointer-events: none;
            z-index: 50;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .scroll-top.visible {
            opacity: 1;
            transform: translateY(0);
            pointer-events: auto;
        }
        .scroll-top:hover {
            background: rgba(124, 58, 237, 0.14);
            border-color: rgba(124, 58, 237, 0.28);
            color: #fff;
            transform: translateY(-3px);
            box-shadow: 0 0 28px rgba(124, 58, 237, 0.14);
        }