:root {
            --bg-color: #ffffff;
            --text-main: #1a1a2e;
            --text-muted: #4a5568;
            --brand-color: #1a73e8;
            --brand-hover: #1557b0;
            --brand-light: #e8f0fe;
            --surface-light: #f7f8fa;
            --border-color: #e2e8f0;
            --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
            --card-shadow-hover: 0 10px 25px rgba(26, 115, 232, 0.08), 0 4px 10px rgba(0, 0, 0, 0.04);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
            color: var(--text-main);
            background-color: var(--bg-color);
            line-height: 1.7;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        header {
            border-bottom: 1px solid var(--border-color);
            position: sticky;
            top: 0;
            background: rgba(255, 255, 255, 0.92);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            z-index: 100;
            box-shadow: 0 1px 0 rgba(0, 0, 0, 0.02);
        }

        .nav-container {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 14px 24px;
        }

        .logo-box {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            transition: opacity 0.2s;
        }
        .logo-box:hover {
            opacity: 0.85;
        }
        .logo-box svg {
            width: 30px;
            height: 30px;
            fill: var(--brand-color);
        }
        .logo-text {
            font-size: 20px;
            font-weight: 700;
            color: var(--brand-color);
            letter-spacing: -0.3px;
        }

        nav {
            display: flex;
            gap: 28px;
        }
        nav a {
            text-decoration: none;
            color: var(--text-muted);
            font-weight: 500;
            transition: color 0.2s;
            font-size: 14.5px;
            position: relative;
        }
        nav a:hover,
        nav a.active {
            color: var(--brand-color);
        }
        nav a.active::after {
            content: '';
            position: absolute;
            bottom: -6px;
            left: 0;
            right: 0;
            height: 2px;
            background: var(--brand-color);
            border-radius: 1px;
        }

        .faq-hero {
            max-width: 860px;
            margin: 0 auto;
            text-align: center;
            padding: 60px 24px 32px 24px;
        }
        .faq-hero h1 {
            font-size: 42px;
            font-weight: 800;
            letter-spacing: -1.2px;
            margin-bottom: 16px;
            color: #0f172a;
            line-height: 1.25;
        }
        .faq-hero p {
            font-size: 17px;
            color: var(--text-muted);
            max-width: 680px;
            margin: 0 auto;
            line-height: 1.75;
        }

        /* 搜索与分类筛选栏 */
        .faq-toolbar {
            max-width: 800px;
            margin: 0 auto 40px auto;
            padding: 0 24px;
            display: flex;
            flex-direction: column;
            gap: 20px;
        }

        .search-box {
            position: relative;
            width: 100%;
        }
        .search-box input {
            width: 100%;
            padding: 14px 48px 14px 20px;
            border: 1px solid var(--border-color);
            border-radius: 50px;
            font-size: 15px;
            background: #fff;
            transition: border-color 0.2s, box-shadow 0.2s;
            outline: none;
        }
        .search-box input:focus {
            border-color: var(--brand-color);
            box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.15);
        }
        .search-icon {
            position: absolute;
            right: 16px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-muted);
            pointer-events: none;
        }

        .filter-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            justify-content: center;
        }
        .filter-tag {
            padding: 8px 20px;
            border-radius: 20px;
            background: var(--surface-light);
            border: 1px solid var(--border-color);
            font-size: 13.5px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s;
            color: var(--text-muted);
            user-select: none;
        }
        .filter-tag.active,
        .filter-tag:hover {
            background: var(--brand-light);
            border-color: var(--brand-color);
            color: var(--brand-color);
            font-weight: 600;
        }

        /* 主内容区 */
        .layout-container {
            max-width: 860px;
            margin: 0 auto;
            padding: 0 24px 72px 24px;
        }

        .faq-section {
            margin-bottom: 48px;
        }
        .faq-section h2 {
            font-size: 22px;
            font-weight: 700;
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--brand-light);
            color: #0f172a;
            letter-spacing: -0.3px;
        }

        .faq-item {
            background: #ffffff;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            margin-bottom: 16px;
            box-shadow: var(--card-shadow);
            transition: all 0.25s;
            overflow: hidden;
        }
        .faq-item:hover {
            border-color: #cbd5e1;
            box-shadow: var(--card-shadow-hover);
        }

        .faq-question {
            padding: 20px 24px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: #0f172a;
            transition: color 0.2s;
            user-select: none;
        }
        .faq-question:hover {
            color: var(--brand-color);
        }
        .faq-question::after {
            content: '+';
            font-size: 20px;
            font-weight: 400;
            color: var(--brand-color);
            transition: transform 0.3s;
        }
        .faq-item.open .faq-question::after {
            transform: rotate(45deg);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.4s ease, padding 0.3s;
            font-size: 15px;
            color: var(--text-muted);
            line-height: 1.75;
            padding: 0 24px;
        }
        .faq-item.open .faq-answer {
            max-height: 400px; /* 足够容纳答案 */
            padding: 0 24px 20px 24px;
        }

        .faq-answer a {
            color: var(--brand-color);
            text-decoration: underline;
        }

        .no-results {
            text-align: center;
            padding: 40px;
            color: var(--text-muted);
            font-size: 15px;
            display: none;
        }

        /* 提示卡片 */
        .tip-banner {
            background: #fef9e7;
            border: 1px solid #fde68a;
            border-radius: var(--radius-md);
            padding: 20px 24px;
            margin: 32px 0;
            display: flex;
            align-items: flex-start;
            gap: 14px;
        }
        .tip-banner::before {
            content: '💡';
            font-size: 20px;
            flex-shrink: 0;
        }
        .tip-banner p {
            margin: 0;
            font-size: 14.5px;
            color: #92400e;
        }

        footer {
            border-top: 1px solid var(--border-color);
            padding: 64px 24px 36px 24px;
            background-color: #111827;
            color: #9ca3af;
        }
        .footer-grid {
            max-width: 1200px;
            margin: 0 auto 52px auto;
            display: grid;
            grid-template-columns: 2fr repeat(4, 1fr);
            gap: 36px;
        }
        @media (max-width: 900px) {
            .footer-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        @media (max-width: 480px) {
            .footer-grid {
                grid-template-columns: 1fr;
            }
            nav {
                display: none;
            }
            .faq-hero h1 {
                font-size: 32px;
            }
        }
        .footer-brand h4 {
            color: #fff;
            font-size: 17px;
            margin-bottom: 14px;
            display: flex;
            align-items: center;
            gap: 8px;
            font-weight: 700;
        }
        .footer-brand h4 svg {
            width: 22px;
            height: 22px;
            fill: var(--brand-color);
        }
        .footer-brand p {
            font-size: 13.5px;
            line-height: 1.7;
            color: #9ca3af;
        }
        .footer-col h5 {
            color: #fff;
            font-size: 14px;
            margin-bottom: 18px;
            font-weight: 600;
            letter-spacing: 0.2px;
        }
        .footer-col ul {
            list-style: none;
        }
        .footer-col ul li {
            margin-bottom: 10px;
        }
        .footer-col ul li a {
            color: #9ca3af;
            text-decoration: none;
            font-size: 13.5px;
            transition: color 0.2s;
        }
        .footer-col ul li a:hover {
            color: #fff;
        }
        .footer-bottom {
            max-width: 1200px;
            margin: 0 auto;
            padding-top: 26px;
            border-top: 1px solid #1f2937;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 13px;
        }
        @media (max-width: 640px) {
            .footer-bottom {
                flex-direction: column;
                gap: 14px;
                text-align: center;
            }
        }
        .footer-bottom-links {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }
        .footer-bottom-links a {
            color: #9ca3af;
            text-decoration: none;
            font-size: 13px;
            transition: color 0.2s;
        }
        .footer-bottom-links a:hover {
            color: #fff;
        }