:root{--ink:#17223b;--muted:#566580;--blue:#2454ce;--line:#e1e7f1;--paper:#fafbff}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:100px}body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button,input{font:inherit}button,summary{cursor:pointer}button{color:inherit}h1,h2,p,figure{margin:0}[hidden]{display:none!important}.wrap{width:calc(100% - 96px);max-width:1168px;margin-inline:auto}a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible{outline:3px solid #9bb4ff;outline-offset:4px;border-radius:5px}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}.skip-link{position:fixed;top:12px;left:12px;transform:translateY(-150%);z-index:20;background:#fff;padding:12px}.skip-link:focus{transform:none}.site-header{position:sticky;top:0;z-index:10;background:#fafbfff5;border-bottom:1px solid var(--line);backdrop-filter:blur(16px)}.header-inner{height:78px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:inline-flex}.brand img{display:block;width:154px;height:auto}.header-inner nav{display:flex;align-items:center;gap:30px;font-size:13px}.header-inner nav a:hover{color:var(--blue)}.back-home{padding:10px 17px;border:1px solid #d4dff5;border-radius:8px;background:#fff}.back-home span{margin-left:9px}.hero{text-align:center;padding:76px 0 52px}.eyebrow{font-size:10px;font-weight:600;letter-spacing:2.1px;color:var(--blue);line-height:1.7}.hero h1{margin:18px 0 20px;font-size:42px;line-height:1.4;font-weight:600;letter-spacing:-1.4px}.hero h1 span{color:var(--blue)}.hero-description{font-size:15px;line-height:1.95;color:var(--muted)}.search-box{display:flex;align-items:center;gap:14px;max-width:620px;margin:30px auto 18px;padding:0 19px;border:1px solid #d8e1f3;border-radius:12px;background:#fff;box-shadow:0 6px 24px #28477807}.search-box:focus-within{border-color:#91abed;box-shadow:0 0 0 3px #315bd90b}.search-box svg{width:20px;height:20px;color:#7b8baa;flex:none}.search-box input{height:56px;width:100%;min-width:0;border:0;background:none;color:var(--ink);font-size:14px;outline:none}.search-box input::-webkit-search-cancel-button{display:none}.search-box input::placeholder{color:#8792a8}.search-box button{border:0;background:#f1f4fa;width:28px;height:28px;flex:none;border-radius:50%;font-size:20px;color:var(--muted)}.document-meta{margin-top:20px;color:#8390a6;font-size:11px}.document-meta span{margin:0 12px}.document-layout{display:grid;grid-template-columns:208px minmax(0,1fr);gap:56px;align-items:start;padding-bottom:64px}.sidebar{position:sticky;top:110px;max-height:calc(100vh - 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@media(min-width:1600px){.wrap{max-width:1240px}.document-layout{gap:72px}}
@media(max-width:1000px){.wrap{width:calc(100% - 56px)}.document-layout{grid-template-columns:175px minmax(0,1fr);gap:28px}.category-nav a{font-size:12px;padding-inline:10px}.hero h1{font-size:37px}.answer{padding-right:25px}.contact-section{padding:34px}}
@media(max-width:700px){html{scroll-padding-top:88px}.wrap{width:calc(100% - 40px)}.header-inner{height:68px;gap:16px}.brand img{width:116px}.header-inner nav{gap:14px;font-size:11px}.back-home{padding:8px 10px}.back-home span{display:none}.hero{padding:44px 0 30px}.hero h1{font-size:30px;letter-spacing:-.8px;margin-top:14px}.hero h1 span{display:block}.hero-description{font-size:13px}.search-box{padding-inline:13px;gap:9px;margin-top:24px}.search-box input{height:52px;font-size:12px}.document-meta{font-size:10px}.document-meta span{margin:0 7px}.document-layout{grid-template-columns:1fr;gap:28px;padding-bottom:34px}.sidebar{position:static;max-height:none;overflow:visible}.nav-label{margin:0 0 12px}.category-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:6px}.category-nav a{padding:10px 12px;background:#f1f4fa;font-size:12px}.sidebar-help{display:none}.document-toolbar{margin-bottom:20px}.category-heading{gap:12px;margin-bottom:16px}.category-heading h2{font-size:22px}.category-intro{font-size:11px}.category-number{width:32px;height:32px;font-size:11px}.faq-category{margin-bottom:34px}.question summary{padding:19px 17px;font-size:13px;gap:17px}.answer{font-size:12px;padding:0 17px 22px}.contact-section{padding:29px 24px;gap:24px;flex-direction:column;align-items:flex-start;margin-bottom:35px}.contact-section h2{font-size:23px}.contact-section figure{align-self:center}.contact-section p:not(.eyebrow){font-size:12px}.footer{font-size:10px;padding-bottom:22px}.document-note{font-size:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
/* Two-level contents keep topics compact and questions directly reachable. */
.document-layout{grid-template-columns:270px minmax(0,1fr);gap:40px}.sidebar{scrollbar-width:thin;scrollbar-color:#d7e0f0 transparent;padding-right:5px}.category-nav{display:block}.toc-group{margin-bottom:4px}.toc-group>summary{display:flex;align-items:center;justify-content:space-between;gap:12px;list-style:none;padding:11px 12px;border-radius:8px;font-size:13px;line-height:1.7;color:#586780;font-weight:500}.toc-group>summary::-webkit-details-marker{display:none}.toc-group>summary::after{content:'';width:6px;height:6px;border-right:1.5px solid currentColor;border-bottom:1.5px solid currentColor;transform:rotate(-45deg);flex:none;margin-right:4px;transition:transform .18s}.toc-group[open]>summary::after{transform:rotate(45deg)}.toc-group>summary:hover{background:#f0f3fb;color:var(--blue)}.toc-group[data-current]>summary,.toc-group[open]>summary{background:#dce7ff;color:#204dbf}.toc-group>ul{list-style:none;margin:7px 0 12px 12px;padding:0 0 0 10px;border-left:1px solid #dce5f5}.category-nav .toc-group a{display:block;padding:8px 10px;font-size:11px;font-weight:400;line-height:1.8;overflow-wrap:anywhere}.category-nav .toc-group a[aria-current="location"]{color:#204dbf;background:#e4edff;font-weight:500}.answer .answer-lead{color:#43526c}.answer h3{font-size:13px;font-weight:600;color:#263b61;line-height:1.8;margin:21px 0 10px}.answer ul{margin:0 0 20px;padding-left:19px}.answer li{padding-left:3px;margin:8px 0}.answer li::marker{color:#8198ca}.answer{padding-right:30px}
@media(max-width:1000px){.document-layout{grid-template-columns:235px minmax(0,1fr);gap:24px}.answer{padding-right:24px}.toc-group>summary{font-size:12px}}
@media(max-width:700px){.document-layout{grid-template-columns:1fr;gap:24px}.sidebar{padding-right:0}.category-nav{max-height:380px;overflow-y:auto;overscroll-behavior:contain;padding:5px;border:1px solid var(--line);border-radius:12px;background:#fff}.category-nav .toc-group a{background:none;font-size:12px}.toc-group>summary{font-size:13px}.answer{padding-right:17px}.answer h3{font-size:12px}.answer ul{padding-left:17px}}