/* ================= 基础设计变量 ================= */
        :root {
            --ink: #050810;
            --ink-2: #080D19;
            --panel: #0C1526;
            --line: rgba(148, 178, 220, .16);
            --line-soft: rgba(148, 178, 220, .09);
            --text: #EDF4FF;
            --muted: #9FB0C9;
            --muted-2: #7E90AA;
            --cyan: #22D3EE;
            --green: #4ADE80;
            --grad: linear-gradient(120deg, #22D3EE 0%, #4ADE80 100%);
            --light: #F3F7FD;
            --dark: #0B1424;
            --dark-muted: #54637B;
            --ease: cubic-bezier(.22, .61, .36, 1);
        }

        * { margin: 0; padding: 0; box-sizing: border-box; }
        html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", sans-serif;
            background: var(--ink);
            color: var(--text);
            line-height: 1.7;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
        }
        body.page-faq { background: var(--ink); color: var(--text); }
        img { max-width: 100%; display: block; }
        a { color: inherit; text-decoration: none; }
        ul, ol { list-style: none; }
        button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
        summary { cursor: pointer; }
        [hidden] { display: none !important; }
        :focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; border-radius: 6px; }
        section[id] { scroll-margin-top: 96px; }
        .container { width: 100%; max-width: 1220px; margin: 0 auto; padding: 0 28px; }
        .svg-sprite { position: absolute; width: 0; height: 0; overflow: hidden; }
        .icon {
            display: inline-block; flex: none; width: 1em; height: 1em;
            fill: none; stroke: currentColor; stroke-width: 1.8;
            stroke-linecap: round; stroke-linejoin: round;
        }
        .visually-hidden {
            position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
            overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap; border: 0;
        }
        .skip-link {
            position: fixed; left: 16px; top: -80px; z-index: 200;
            padding: 10px 18px; border-radius: 10px;
            background: var(--grad); color: #03242C; font-size: 14px; font-weight: 700;
            transition: top .2s var(--ease);
        }
        .skip-link:focus { top: 14px; }
        main:focus { outline: none; }

        /* ================= 顶部导航 ================= */
        .site-header { position: sticky; top: 0; z-index: 100; }
        .navbar { background: rgba(5, 8, 16, .78); border-bottom: 1px solid var(--line-soft); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); }
        .nav-inner { display: flex; align-items: center; height: 74px; gap: 20px; }
        .brand { display: flex; align-items: center; gap: 10px; flex: none; }
        .brand img { height: 30px; width: auto; }
        .brand-tag {
            font-size: 11px; font-weight: 700; letter-spacing: .1em; color: #A5F3FC;
            border: 1px solid rgba(34, 211, 238, .35); background: rgba(34, 211, 238, .08);
            padding: 3px 8px; border-radius: 999px;
        }
        .nav-links { display: flex; align-items: center; gap: 4px; margin-left: 28px; }
        .nav-links a {
            display: inline-flex; align-items: center; height: 40px; padding: 0 14px; border-radius: 9px;
            font-size: 14.5px; font-weight: 500; color: var(--muted);
            transition: color .2s var(--ease), background-color .2s var(--ease);
        }
        .nav-links a:hover { color: var(--text); background: rgba(255, 255, 255, .05); }
        .nav-links a.active { color: var(--text); position: relative; }
        .nav-links a.active::after {
            content: ""; position: absolute; left: 14px; right: 14px; bottom: 2px; height: 2px;
            border-radius: 2px; background: var(--grad);
        }
        .nav-right { margin-left: auto; display: flex; align-items: center; }
        .btn-nav {
            display: inline-flex; align-items: center; gap: 7px; height: 42px; padding: 0 18px;
            border-radius: 10px; background: var(--grad); color: #03242C;
            font-size: 14px; font-weight: 700;
            transition: transform .2s var(--ease), box-shadow .25s var(--ease);
        }
        .btn-nav .icon { width: 16px; height: 16px; }
        .btn-nav:hover { transform: translateY(-1px); box-shadow: 0 12px 26px -12px rgba(34, 211, 238, .8); }
        .menu-toggle {
            display: none; align-items: center; justify-content: center; flex-direction: column; gap: 5px;
            width: 44px; height: 44px; margin-left: auto;
            border: 1px solid var(--line); border-radius: 10px; background: rgba(255, 255, 255, .03);
        }
        .menu-toggle span { display: block; width: 18px; height: 2px; border-radius: 2px; background: var(--text); transition: transform .25s var(--ease), opacity .2s; }
        .menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
        .menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
        .menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
        .nav-mobile-cta { display: none; }

        /* ================= 帮助中心首屏 ================= */
        .help-hero {
            position: relative; overflow: hidden; padding: 64px 0 54px;
            background:
                radial-gradient(900px 500px at 82% -8%, rgba(34, 211, 238, .15), transparent 62%),
                radial-gradient(760px 460px at 4% 6%, rgba(74, 222, 128, .1), transparent 60%),
                var(--ink);
            border-bottom: 1px solid var(--line-soft);
        }
        .help-hero::before {
            content: ""; position: absolute; inset: 0; pointer-events: none;
            background-image:
                linear-gradient(to right, rgba(148, 178, 220, .055) 1px, transparent 1px),
                linear-gradient(to bottom, rgba(148, 178, 220, .055) 1px, transparent 1px);
            background-size: 72px 72px;
            -webkit-mask-image: radial-gradient(ellipse 72% 64% at 64% 24%, #000 18%, transparent 74%);
            mask-image: radial-gradient(ellipse 72% 64% at 64% 24%, #000 18%, transparent 74%);
        }
        .help-hero .container { position: relative; }
        .help-hero .breadcrumb { display: flex; align-items: center; gap: 8px; margin-bottom: 24px; font-size: 12.5px; color: var(--muted-2); }
        .help-hero .breadcrumb a { color: var(--muted); }
        .help-hero .breadcrumb a:hover { color: var(--text); }
        .help-hero .breadcrumb [aria-current="page"] { color: var(--text); }
        .help-hero h1 { margin: 16px 0 14px; font-size: clamp(32px, 4.4vw, 46px); line-height: 1.18; letter-spacing: -.02em; font-weight: 800; color: var(--text); }
        .help-hero .eyebrow {
            display: inline-flex; align-items: center; gap: 8px;
            padding: 6px 14px; border-radius: 999px;
            font-size: 12.5px; font-weight: 600; letter-spacing: .04em;
            color: #A5F3FC; background: rgba(34, 211, 238, .07); border: 1px solid rgba(34, 211, 238, .28);
        }
        .help-lead { max-width: 650px; font-size: 16px; color: var(--muted); line-height: 1.85; }

        .help-search { position: relative; max-width: 620px; margin: 28px 0 22px; }
        .help-search .icon {
            position: absolute; left: 18px; top: 50%; transform: translateY(-50%);
            width: 18px; height: 18px; color: var(--muted-2); pointer-events: none;
        }
        .help-search input {
            width: 100%; min-height: 54px; padding: 0 18px 0 48px;
            border: 1px solid var(--line); border-radius: 14px;
            background: #0C1526; color: var(--text); font: inherit; font-size: 15px;
            box-shadow: 0 20px 40px -30px rgba(0, 0, 0, .8);
            transition: border-color .2s var(--ease), box-shadow .2s var(--ease);
        }
        .help-search input::placeholder { color: var(--muted-2); }
        .help-search input:focus { border-color: var(--cyan); box-shadow: 0 0 0 4px rgba(34, 211, 238, .12); outline: none; }

        .help-cats { display: flex; flex-wrap: wrap; gap: 8px; }
        .help-cats a {
            display: inline-flex; align-items: center; gap: 7px;
            padding: 7px 12px; border-radius: 999px;
            border: 1px solid var(--line); background: rgba(255, 255, 255, .03);
            font-size: 12.5px; font-weight: 600; color: #B9C8DC;
            transition: border-color .2s, color .2s, transform .2s;
        }
        .help-cats a:hover { border-color: rgba(34, 211, 238, .5); color: #A5F3FC; transform: translateY(-1px); }
        .help-cats em { font-style: normal; font-size: 11px; color: var(--muted-2); }

        /* ================= 帮助中心主体 ================= */
        .help-body { padding: 56px 0 96px; background: var(--ink); }
        .help-layout { display: grid; grid-template-columns: 250px minmax(0, 1fr); gap: 48px; align-items: start; }
        .help-side { position: sticky; top: 100px; }
        .help-side h2 { font-size: 13px; letter-spacing: .08em; color: var(--muted-2); margin-bottom: 14px; font-weight: 700; }
        .help-nav { display: flex; flex-direction: column; gap: 3px; }
        .help-nav a {
            display: flex; align-items: center; justify-content: space-between; gap: 10px;
            padding: 10px 12px; border-radius: 10px;
            font-size: 14px; color: #B9C8DC;
            transition: background-color .2s, color .2s;
        }
        .help-nav a:hover { background: rgba(255, 255, 255, .05); color: var(--text); }
        .help-nav em { font-style: normal; font-size: 11px; color: var(--muted-2); background: rgba(255, 255, 255, .06); padding: 1px 7px; border-radius: 999px; }
        .help-side-card {
            margin-top: 22px; padding: 20px; border-radius: 14px;
            background: linear-gradient(170deg, #0E1A2C, #080E1A); border: 1px solid var(--line-soft);
            box-shadow: 0 16px 34px -32px rgba(0, 0, 0, .6);
        }
        .help-side-card h3 { font-size: 14.5px; color: var(--text); margin-bottom: 7px; }
        .help-side-card p { font-size: 12.5px; color: var(--muted-2); line-height: 1.75; }
        .help-side-link { display: inline-flex; align-items: center; gap: 6px; margin-top: 10px; font-size: 13px; font-weight: 700; color: #67E8F9; }
        .help-side-link:hover { color: #A5F3FC; }
        .help-side-link .icon { width: 15px; height: 15px; }

        .faq-group { margin-bottom: 46px; }
        .faq-group:last-child { margin-bottom: 0; }
        .faq-group > h2 { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; font-size: 23px; color: var(--text); letter-spacing: -.01em; }
        .faq-group > h2 em { font-style: normal; font-size: 11px; font-weight: 600; color: #67E8F9; background: rgba(34, 211, 238, .1); padding: 2px 8px; border-radius: 999px; }
        .qa-list { display: flex; flex-direction: column; gap: 10px; }
        .qa { background: rgba(255, 255, 255, .03); border: 1px solid var(--line-soft); border-radius: 12px; transition: border-color .2s, box-shadow .2s; }
        .qa[open] { border-color: rgba(34, 211, 238, .35); box-shadow: 0 16px 30px -30px rgba(0, 0, 0, .7); }
        .qa summary { display: flex; align-items: center; gap: 12px; padding: 16px 18px; list-style: none; font-size: 15.5px; font-weight: 600; color: var(--text); line-height: 1.6; }
        .qa summary::-webkit-details-marker { display: none; }
        .qa summary::marker { content: ""; }
        .qa summary::after {
            content: ""; flex: none; width: 10px; height: 10px; margin-left: auto;
            border-right: 2px solid var(--muted-2); border-bottom: 2px solid var(--muted-2);
            transform: rotate(45deg) translateY(-2px); transition: transform .25s var(--ease);
        }
        .qa[open] summary::after { transform: rotate(-135deg) translateY(-2px); }
        .qa p { padding: 0 18px 18px; font-size: 14.5px; color: var(--muted); line-height: 1.85; }
        .qa p strong { color: var(--text); }

        .search-empty {
            padding: 28px; border-radius: 14px; background: rgba(255, 255, 255, .03); border: 1px solid var(--line-soft);
            color: var(--muted); font-size: 14px; line-height: 1.8;
        }
        .search-empty strong { display: block; margin-bottom: 4px; color: var(--text); }
        .search-empty a { color: #67E8F9; font-weight: 700; text-decoration: underline; text-underline-offset: 4px; }
        .search-empty a:hover { color: #A5F3FC; }
        .search-empty button { margin-top: 10px; font-size: 13px; font-weight: 700; color: #67E8F9; text-decoration: underline; text-underline-offset: 4px; }

        /* ================= 页脚 ================= */
        .site-footer { padding: 56px 0 30px; background: #04070E; border-top: 1px solid var(--line-soft); color: var(--text); }
        .footer-top { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 40px; }
        .footer-brand img { height: 28px; width: auto; margin-bottom: 14px; }
        .footer-brand p { max-width: 300px; font-size: 13px; color: var(--muted-2); line-height: 1.8; }
        .footer-col h3 { margin-bottom: 14px; font-size: 12.5px; font-weight: 700; letter-spacing: .06em; color: #C9D7E8; }
        .footer-col ul { display: flex; flex-direction: column; gap: 9px; }
        .footer-col a { font-size: 13px; color: var(--muted-2); transition: color .2s; }
        .footer-col a:hover { color: #67E8F9; }
        .footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px 24px; margin-top: 40px; padding-top: 22px; border-top: 1px solid var(--line-soft); font-size: 12px; color: #6B7C95; }

        /* ================= 响应式 ================= */
        @media (max-width: 1100px) {
            .footer-top { grid-template-columns: 1.2fr 1fr 1fr; }
        }
        @media (max-width: 992px) {
            .menu-toggle { display: flex; }
            .nav-right { display: none; }
            .brand-tag { display: none; }
            .nav-links {
                position: absolute; top: 100%; left: 0; right: 0; z-index: 99;
                display: flex; flex-direction: column; align-items: stretch; gap: 2px;
                margin: 0; padding: 12px 20px 18px;
                background: #080D19; border-bottom: 1px solid var(--line);
                box-shadow: 0 30px 50px -30px rgba(0, 0, 0, .9);
                transform: translateY(-8px); opacity: 0; visibility: hidden; pointer-events: none;
                transition: transform .25s var(--ease), opacity .2s, visibility .25s;
                max-height: calc(100dvh - 74px); overflow-y: auto;
            }
            .nav-links.is-open { transform: none; opacity: 1; visibility: visible; pointer-events: auto; }
            .nav-links a { height: auto; padding: 12px 14px; border-radius: 10px; font-size: 15px; color: var(--text); }
            .nav-links a.active { background: rgba(255, 255, 255, .05); }
            .nav-links a.active::after { display: none; }
            .nav-mobile-cta { display: block; margin-top: 10px; }
            .nav-links .nav-mobile-cta a {
                width: 100%; padding: 0 26px; min-height: 50px; font-size: 15px; font-weight: 700;
                color: #03242C; background: var(--grad); justify-content: center;
            }
            .help-layout { grid-template-columns: 1fr; gap: 30px; }
            .help-side { position: static; }
            .help-nav { flex-direction: row; flex-wrap: wrap; gap: 8px; }
            .help-nav a { border: 1px solid var(--line); background: rgba(255, 255, 255, .03); padding: 8px 12px; font-size: 13px; }
            .help-nav em { background: rgba(255, 255, 255, .06); }
            .footer-top { grid-template-columns: 1fr 1fr; }
        }
        @media (max-width: 700px) {
            .container { padding: 0 20px; }
            .help-hero { padding: 40px 0 36px; }
            .help-hero h1 { font-size: 32px; }
            .help-search input { min-height: 50px; font-size: 14px; padding-left: 44px; }
            .help-cats a { font-size: 12px; }
            .help-body { padding: 40px 0 72px; }
            .faq-group > h2 { font-size: 21px; }
            .qa summary { font-size: 15px; padding: 14px 16px; }
            .qa p { padding: 0 16px 16px; font-size: 14px; }
            .footer-top { grid-template-columns: 1fr; gap: 28px; }
            .footer-bottom { flex-direction: column; }
        }
        @media (prefers-reduced-motion: reduce) {
            html { scroll-behavior: auto; }
            *, *::before, *::after {
                animation-duration: .001ms !important;
                animation-iteration-count: 1 !important;
                transition-duration: .001ms !important;
            }
        }
    

            .help-search { display: none; }
            @media (max-width: 992px) {
                .menu-toggle { display: none; }
                .site-header { position: static; }
                .nav-inner { flex-wrap: wrap; height: auto; padding-block: 12px; }
                .nav-links {
                    position: static; display: flex; flex-direction: column; width: 100%;
                    margin: 6px 0 0; padding: 0; border: 0; box-shadow: none; background: transparent;
                    opacity: 1; visibility: visible; transform: none; pointer-events: auto;
                    max-height: none; overflow: visible;
                }
                .nav-links a { height: auto; padding: 10px 14px; }
                .nav-mobile-cta { display: block; margin: 6px 0 0; }
                .nav-right { display: none; }
            }