:root {
            --bg-color: #f7f9fc;
            --surface-color: #ffffff;
            --border-color: #e8ecf1;
            --border-hover: #cdd5df;
            --text-primary: #0b1a30;
            --text-secondary: #3d4f63;
            --text-muted: #5e6f82;
            --brand-primary: #1a5fdc;
            --brand-hover: #1349b0;
            --brand-light: #eef4ff;
            --brand-border: #c5d9fc;
            --brand-glow: rgba(26, 95, 220, 0.12);
            --accent-teal: #0d9488;
            --accent-amber: #d97706;
            --accent-rose: #e11d48;
            --accent-green: #16a34a;
            --gradient-hero: linear-gradient(135deg, #f0f5ff 0%, #f8fafd 40%, #eef6f9 100%);
            --gradient-card: linear-gradient(160deg, #ffffff 0%, #f9fbfd 100%);
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.03);
            --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.04), 0 2px 6px rgba(0, 0, 0, 0.02);
            --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.05), 0 4px 10px rgba(0, 0, 0, 0.03);
            --radius-sm: 8px;
            --radius-md: 14px;
            --radius-lg: 20px;
            --transition-fast: 0.18s ease;
            --transition-smooth: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
            background-color: var(--bg-color);
            color: var(--text-primary);
            line-height: 1.65;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            letter-spacing: -0.01em;
        }

        a {
            color: inherit;
            text-decoration: none;
        }

        .container {
            max-width: 1240px;
            margin: 0 auto;
            padding: 0 28px;
        }

        /* HEADER */
        header {
            background-color: rgba(255, 255, 255, 0.88);
            backdrop-filter: blur(14px);
            -webkit-backdrop-filter: blur(14px);
            border-bottom: 1px solid var(--border-color);
            position: sticky;
            top: 0;
            z-index: 100;
            transition: box-shadow var(--transition-smooth);
        }
        header.scrolled {
            box-shadow: var(--shadow-md);
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 74px;
            gap: 20px;
        }

        .brand-link {
            display: flex;
            align-items: center;
            gap: 11px;
            flex-shrink: 0;
            transition: opacity var(--transition-fast);
        }
        .brand-link:hover {
            opacity: 0.85;
        }

        .logo-svg {
            width: 38px;
            height: 38px;
            flex-shrink: 0;
            filter: drop-shadow(0 2px 4px rgba(26, 95, 220, 0.25));
            transition: transform var(--transition-smooth);
        }
        .brand-link:hover .logo-svg {
            transform: scale(1.06);
        }

        .brand-text {
            font-size: 19px;
            font-weight: 700;
            color: var(--text-primary);
            letter-spacing: -0.4px;
            display: flex;
            align-items: center;
            gap: 7px;
            white-space: nowrap;
        }
        .version-tag {
            background: var(--brand-light);
            color: var(--brand-primary);
            border: 1px solid var(--brand-border);
            font-size: 10px;
            font-weight: 700;
            padding: 3px 9px;
            border-radius: 14px;
            letter-spacing: 0.4px;
            animation: tagPulse 3s ease-in-out infinite;
        }
        @keyframes tagPulse {
            0%,
            100% {
                box-shadow: 0 0 0 0 var(--brand-glow);
            }
            50% {
                box-shadow: 0 0 0 6px transparent;
            }
        }

        .nav-menu {
            display: flex;
            list-style: none;
            gap: 8px;
            align-items: center;
        }
        .nav-menu li {
            position: relative;
        }
        .nav-menu a {
            font-size: 14.5px;
            font-weight: 500;
            color: var(--text-secondary);
            padding: 8px 16px;
            border-radius: 20px;
            transition: all var(--transition-fast);
            display: block;
            white-space: nowrap;
            letter-spacing: -0.2px;
        }
        .nav-menu a:hover {
            color: var(--brand-primary);
            background-color: var(--brand-light);
        }
        .nav-menu a.active {
            color: var(--brand-primary);
            background-color: var(--brand-light);
            font-weight: 600;
        }

        /* 护航中心 Hero */
        .faq-hero {
            padding: 48px 0 20px;
            text-align: center;
        }
        .faq-hero h1 {
            font-size: 38px;
            font-weight: 800;
            letter-spacing: -1.2px;
            color: var(--text-primary);
            margin-bottom: 10px;
        }
        .faq-hero .highlight {
            background: linear-gradient(135deg, var(--accent-teal) 0%, var(--brand-primary) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .faq-hero .subtitle {
            font-size: 15px;
            color: var(--text-secondary);
            max-width: 660px;
            margin: 0 auto 20px;
            line-height: 1.6;
        }
        .status-badge {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            background: #f0fdf4;
            border: 1px solid #bbf7d0;
            color: #166534;
            padding: 6px 16px;
            border-radius: 18px;
            font-size: 13px;
            font-weight: 500;
            margin-bottom: 18px;
        }
        .status-badge .dot {
            width: 9px;
            height: 9px;
            background: #22c55e;
            border-radius: 50%;
            animation: pulseDot 1.8s ease-in-out infinite;
        }
        @keyframes pulseDot {
            0%,
            100% {
                box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.45);
            }
            50% {
                box-shadow: 0 0 0 10px rgba(34, 197, 94, 0);
            }
        }

        /* 通用区块 */
        .section-block {
            background: var(--surface-color);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            padding: 38px 32px;
            margin-bottom: 38px;
            box-shadow: var(--shadow-sm);
        }
        .section-block h2 {
            font-size: 24px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 14px;
            letter-spacing: -0.4px;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .section-block h3 {
            font-size: 18px;
            font-weight: 600;
            color: var(--text-primary);
            margin: 18px 0 10px;
        }
        .section-block p {
            font-size: 14px;
            color: var(--text-secondary);
            line-height: 1.7;
            margin-bottom: 12px;
        }
        .grid-2col {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 20px;
            margin-top: 16px;
        }
        .grid-3col {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 20px;
            margin-top: 16px;
        }

        /* 安全仪表卡片 */
        .shield-card {
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 22px 18px;
            background: var(--gradient-card);
            text-align: center;
            transition: all var(--transition-smooth);
            position: relative;
        }
        .shield-card:hover {
            box-shadow: var(--shadow-md);
            border-color: var(--brand-border);
            transform: translateY(-3px);
        }
        .shield-icon {
            font-size: 32px;
            margin-bottom: 8px;
        }
        .shield-status {
            font-size: 14px;
            font-weight: 600;
            color: var(--accent-green);
        }
        .shield-card.warning .shield-status {
            color: var(--accent-amber);
        }
        .shield-card.danger .shield-status {
            color: var(--accent-rose);
        }

        /* 诊断步骤 */
        .diagnostic-steps {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
            margin-top: 18px;
        }
        .diag-step {
            flex: 1;
            min-width: 220px;
            background: #f9fbfd;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 20px 16px;
            text-align: center;
            transition: all var(--transition-smooth);
        }
        .diag-step:hover {
            border-color: var(--brand-border);
            box-shadow: var(--shadow-md);
        }
        .diag-number {
            width: 32px;
            height: 32px;
            background: var(--brand-primary);
            color: #fff;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 10px;
            font-weight: 700;
            font-size: 15px;
        }
        .diag-step h4 {
            font-size: 14px;
            font-weight: 600;
            margin-bottom: 4px;
        }
        .diag-step p {
            font-size: 12px;
            color: var(--text-secondary);
        }

        /* 实践卡片 */
        .practice-card {
            background: var(--surface-color);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 22px 18px;
            transition: all var(--transition-smooth);
            display: flex;
            gap: 14px;
            align-items: flex-start;
        }
        .practice-card:hover {
            box-shadow: var(--shadow-md);
            border-color: var(--brand-border);
        }
        .practice-icon {
            font-size: 26px;
            flex-shrink: 0;
        }
        .practice-text h4 {
            font-size: 15px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 4px;
        }
        .practice-text p {
            font-size: 12.5px;
            color: var(--text-secondary);
            line-height: 1.5;
        }

        /* FAQ 手风琴 */
        .faq-accordion {
            margin-top: 16px;
        }
        .faq-item {
            border: 1px solid var(--border-color);
            border-radius: var(--radius-sm);
            margin-bottom: 10px;
            background: var(--surface-color);
            transition: all var(--transition-fast);
        }
        .faq-question {
            padding: 15px 20px;
            font-weight: 600;
            font-size: 14px;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: var(--text-primary);
            user-select: none;
        }
        .faq-answer {
            padding: 0 20px 16px;
            font-size: 13px;
            color: var(--text-secondary);
            display: none;
            line-height: 1.6;
        }
        .faq-item.open .faq-answer {
            display: block;
        }
        .faq-item.open .faq-question {
            color: var(--brand-primary);
        }

        /* 联系支持 */
        .support-card {
            background: var(--brand-light);
            border: 1px solid var(--brand-border);
            border-radius: var(--radius-lg);
            padding: 32px 28px;
            text-align: center;
            margin: 0 0 38px;
        }
        .support-card h3 {
            font-size: 20px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 8px;
        }
        .support-card p {
            font-size: 13.5px;
            color: var(--text-secondary);
            margin-bottom: 16px;
        }
        .btn-support {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            background: var(--brand-primary);
            color: #fff;
            font-weight: 600;
            padding: 12px 26px;
            border-radius: 24px;
            border: none;
            cursor: pointer;
            font-size: 14px;
            transition: all var(--transition-smooth);
            box-shadow: 0 4px 14px rgba(26, 95, 220, 0.25);
            text-decoration: none;
        }
        .btn-support:hover {
            background: var(--brand-hover);
            box-shadow: 0 6px 20px rgba(26, 95, 220, 0.35);
            transform: translateY(-2px);
        }

        /* FOOTER */
        footer {
            background-color: var(--surface-color);
            border-top: 1px solid var(--border-color);
            padding: 56px 0 28px;
            font-size: 13.5px;
            color: var(--text-secondary);
        }
        .footer-content {
            display: grid;
            grid-template-columns: 2fr repeat(3, 1fr);
            gap: 36px;
            margin-bottom: 40px;
        }
        .footer-brand p {
            margin-top: 10px;
            font-size: 12.5px;
            color: var(--text-muted);
            line-height: 1.6;
        }
        .footer-col h5 {
            font-size: 13.5px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 14px;
        }
        .footer-col ul {
            list-style: none;
        }
        .footer-col li {
            margin-bottom: 9px;
        }
        .footer-col a {
            color: var(--text-secondary);
            transition: color var(--transition-fast);
            font-size: 13px;
        }
        .footer-col a:hover {
            color: var(--brand-primary);
        }
        .footer-bottom-bar {
            border-top: 1px solid var(--border-color);
            padding-top: 22px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 12.5px;
            color: var(--text-muted);
            flex-wrap: wrap;
            gap: 10px;
        }

        @media (max-width: 960px) {
            .grid-2col,
            .grid-3col {
                grid-template-columns: 1fr;
            }
            .diagnostic-steps {
                flex-direction: column;
            }
            .footer-content {
                grid-template-columns: 1fr 1fr;
                gap: 28px;
            }
            .faq-hero h1 {
                font-size: 28px;
            }
        }
        @media (max-width: 600px) {
            .footer-content {
                grid-template-columns: 1fr;
            }
            .section-block {
                padding: 24px 16px;
            }
        }