:root{--bg:#fff;--text:#191919;--muted:#707070;--faint:#f7f7f7;--border:#e8e8e8;--accent:#151515;--header:#fffffff0;--selected:#f0f0f0;--font:Arial,"PingFang SC","Microsoft YaHei",sans-serif;color-scheme:light}
:root[data-theme=dark]{--bg:#111;--text:#ededed;--muted:#a1a1a1;--faint:#191919;--border:#2d2d2d;--accent:#f0f0f0;--header:#111111f2;--selected:#252525;color-scheme:dark}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font);-webkit-font-smoothing:antialiased;font-size:14px}a{color:inherit;text-decoration:none}button,input,select{font:inherit;color:inherit}button{cursor:pointer}a,button,input,summary,select{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible,select:focus-visible{outline:2px solid var(--text);outline-offset:4px}::selection{background:#c9c9c9;color:#111}.skip-link{position:fixed;top:8px;left:8px;z-index:100;background:var(--text);color:var(--bg);padding:12px;transform:translateY(-150%)}.skip-link:focus{transform:none}
.docs-header{height:67px;position:sticky;top:0;z-index:30;display:flex;align-items:center;padding:0 34px;gap:35px;background:var(--header);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}.brand{display:inline-flex;align-items:center;gap:8px;flex-shrink:0}.brand-mark{width:23px;height:23px}.brand>span{font-size:26px;font-weight:800;letter-spacing:-1.5px}.brand i{width:1px;height:18px;background:var(--border);margin:0 10px}.brand b{font-weight:500;font-size:15px;letter-spacing:-.3px}.search-open{display:flex;justify-content:space-between;align-items:center;gap:50px;font-size:12px;color:var(--muted);padding:9px 12px;border:1px solid var(--border);border-radius:6px;background:var(--faint);margin-left:34px;width:255px}.search-open:hover{border-color:var(--muted)}kbd{font:10px var(--font);border:1px solid var(--border);padding:2px 4px;border-radius:3px;white-space:nowrap}.header-nav{display:flex;align-items:center;gap:25px;font-size:12px;margin-left:auto}.header-nav>a:first-child{color:var(--muted)}.trade-button{background:var(--text);color:var(--bg);padding:9px 13px;border-radius:5px;white-space:nowrap}#theme-toggle{border:0;background:none;font-size:23px;padding:2px 0;width:27px;line-height:1}#menu-toggle{display:none;border:0;background:none;padding:6px}#menu-toggle span{height:1px;width:20px;background:var(--text);display:block;margin:5px 0}
.doc-layout{width:min(1480px,100%);margin:auto;display:grid;grid-template-columns:218px minmax(0,740px) 175px;gap:60px;padding:0 34px}.sidebar{position:sticky;top:90px;align-self:start;height:calc(100dvh - 110px);overflow:auto;padding-top:13px;padding-bottom:25px;scrollbar-width:thin}.sidebar-head{display:none}.sidebar-home{display:block;padding:10px 11px;font-size:13px;color:var(--muted);border-radius:5px;margin-bottom:25px}.nav-group{margin:0 0 29px}.nav-group h2{font-size:12px;font-weight:600;margin:0 0 10px;padding:0 11px;color:var(--text)}.nav-group>a{display:block;padding:9px 11px;color:var(--muted);font-size:12px;line-height:1.45;border-radius:5px;margin:2px 0}.nav-group>a:hover,.sidebar-home:hover{background:var(--faint);color:var(--text)}.sidebar .current{background:var(--selected);color:var(--text);font-weight:500}.sidebar-bottom{border-top:1px solid var(--border);padding:18px 11px 0;display:flex;flex-direction:column;gap:14px;font-size:11px;color:var(--muted)}
.main-content{min-width:0;padding-top:47px}.breadcrumb{display:flex;align-items:center;gap:10px;font-size:11px;color:var(--muted);margin-bottom:27px}.breadcrumb a:hover{text-decoration:underline}.article-heading h1{font-size:36px;font-weight:650;letter-spacing:-1.1px;line-height:1.4;margin:0 0 18px}.article-heading>p{font-size:15px;color:var(--muted);line-height:1.9;margin:0}.article-meta{display:flex;justify-content:space-between;gap:20px;font-size:10px;color:var(--muted);align-items:center;margin:25px 0 33px;padding-bottom:25px;border-bottom:1px solid var(--border)}.copy-page{background:none;border:0;font-size:10px;color:var(--muted);padding:5px 0}.copy-page:hover{color:var(--text)}.prose{font-size:14px;line-height:1.95}.prose>section{margin-bottom:38px}.prose h2{font-size:22px;letter-spacing:-.5px;font-weight:600;line-height:1.5;margin:0 0 16px;display:flex;gap:12px;align-items:center}.heading-anchor{font-size:16px;color:var(--muted);opacity:0}.prose h2:hover .heading-anchor,.heading-anchor:focus{opacity:1}.prose p{margin:12px 0;color:var(--muted)}.prose strong,.prose b{color:var(--text)}.prose a:not(.heading-anchor){text-decoration:underline;text-underline-offset:4px;color:var(--text)}.prose ul,.prose ol{padding-left:22px;margin:14px 0}.prose li{padding-left:3px;margin:9px 0;color:var(--muted)}.note{background:var(--faint);border:1px solid var(--border);border-left:3px solid var(--text);border-radius:5px;padding:18px 21px;margin:22px 0}.note b{font-size:12px}.note p{font-size:12px;line-height:1.9;margin:9px 0 0}.note.warning{border-left-color:#8c795d}.formula{font-size:13px;line-height:1.8;background:var(--faint);padding:18px 21px;border:1px solid var(--border);border-radius:5px;margin:21px 0;overflow-wrap:anywhere}.caption{font-size:11px!important;color:var(--muted);line-height:1.8}.table-wrap{width:100%;overflow:auto;border:1px solid var(--border);border-radius:5px;margin:23px 0}.table-wrap table{border-collapse:collapse;min-width:470px;width:100%;font-size:12px;line-height:1.8}.table-wrap th{background:var(--faint);text-align:left;font-weight:500;color:var(--text)}.table-wrap th,.table-wrap td{padding:12px 15px;border-bottom:1px solid var(--border);vertical-align:top}.table-wrap td{color:var(--muted)}.table-wrap tr:last-child td{border:0}.table-wrap th:first-child,.table-wrap td:first-child{min-width:120px}.glossary{margin:18px 0}.glossary>div{margin-bottom:21px}.glossary dt{font-size:13px;font-weight:600;color:var(--text);margin-bottom:6px}.glossary dd{margin:0;color:var(--muted);font-size:13px;line-height:1.85}.references{padding-top:26px;border-top:1px solid var(--border)}.references h2{font-size:17px}.references ul{list-style:none;padding:0;margin:0}.references li{font-size:12px;padding:0}.article-pagination{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:38px}.article-pagination a{border:1px solid var(--border);border-radius:6px;padding:17px 19px;display:flex;flex-direction:column;gap:9px;min-width:0}.article-pagination a:last-child{text-align:right}.article-pagination a:hover{border-color:var(--muted)}.article-pagination span{font-size:10px;color:var(--muted)}.article-pagination b{font-size:12px;font-weight:500;line-height:1.6}
.page-toc{position:sticky;top:108px;align-self:start;font-size:11px;padding-top:9px;max-height:calc(100dvh - 140px);overflow:auto}.page-toc>span{display:block;margin-bottom:18px;font-weight:500}.page-toc>a{display:block;color:var(--muted);padding:7px 0 7px 13px;border-left:1px solid var(--border);font-size:10px;line-height:1.7}.page-toc>a:hover,.page-toc>a.active{color:var(--text);border-left-color:var(--text)}.toc-end{margin-top:30px;padding-top:20px;border-top:1px solid var(--border);display:flex;flex-direction:column;gap:12px;font-size:10px;color:var(--muted)}.toc-end a{color:var(--text)}.mobile-toc{display:none}.document-footer{margin:45px 0 25px;padding-top:22px;border-top:1px solid var(--border);color:var(--muted)}.document-footer p{font-size:10px;line-height:1.8;margin:0 0 16px}.document-footer>div{display:flex;justify-content:space-between;gap:15px;font-size:9px;line-height:1.8}.document-footer a:hover{text-decoration:underline}
.home-intro h1{font-size:43px;letter-spacing:-1.5px;line-height:1.35;margin:0 0 24px;font-weight:650}.home-intro p{font-size:15px;color:var(--muted);line-height:1.85;margin:0 0 27px}.primary-link{display:inline-flex;align-items:center;gap:35px;background:var(--text);color:var(--bg);font-size:12px;padding:13px 17px;border-radius:5px}.primary-link:hover{opacity:.8}.home-note{background:var(--faint);padding:19px 22px;border-radius:6px;margin:35px 0 42px;border:1px solid var(--border)}.home-note b{font-size:12px;font-weight:500}.home-note p{font-size:12px;color:var(--muted);line-height:1.85;margin:10px 0 0}.guide-group{margin:0 0 42px}.guide-heading{margin-bottom:20px}.guide-heading h2{font-size:23px;letter-spacing:-.6px;margin:0 0 9px;font-weight:600}.guide-heading>p{color:var(--muted);font-size:12px;margin:0}.guide-links{display:grid;grid-template-columns:1fr 1fr;gap:12px}.guide-links>a{padding:19px 20px;border:1px solid var(--border);border-radius:6px;display:block}.guide-links>a:hover{background:var(--faint);border-color:var(--muted)}.guide-links h3{font-size:13px;font-weight:500;margin:0 0 10px;display:flex;align-items:center;justify-content:space-between;gap:12px;line-height:1.55}.guide-links h3 span{font-size:11px;color:var(--muted)}.guide-links p{font-size:11px;line-height:1.8;color:var(--muted);margin:0}.home-end{margin-top:20px;border-top:1px solid var(--border);padding-top:28px}.home-end h2{font-size:20px;letter-spacing:-.5px;margin:0 0 12px;font-weight:500}.home-end p{font-size:12px;color:var(--muted);line-height:1.8}.plain-link{display:inline-block;font-size:12px;text-decoration:underline;text-underline-offset:4px;margin-top:8px}
.calculator{background:var(--faint);border:1px solid var(--border);border-radius:7px;padding:22px;margin-top:22px}.calculator-top{display:flex;justify-content:space-between;gap:25px;align-items:flex-end}.calculator-top label{display:flex;flex-direction:column;gap:11px;font-size:11px;color:var(--muted)}.calculator-top select{background:var(--bg);border:1px solid var(--border);font-size:12px;padding:8px 11px;border-radius:4px}.calculator-top strong{font-size:22px;font-weight:500;color:var(--text);text-align:right}#expiry-price{width:100%;accent-color:var(--text);margin:23px 0 0;cursor:pointer}.calc-range{display:flex;justify-content:space-between;font-size:10px;color:var(--muted)}.calc-result{border-top:1px solid var(--border);margin-top:20px;padding-top:17px;display:flex;align-items:center;justify-content:space-between;gap:20px}.calc-result span{font-size:12px}.calc-result strong{font-size:25px;font-weight:500;font-variant-numeric:tabular-nums}.calculator .caption{margin-bottom:0}
.search-dialog{width:min(650px,calc(100% - 32px));max-height:78dvh;padding:0;border:1px solid var(--border);border-radius:12px;background:var(--bg);color:var(--text);box-shadow:0 24px 90px #0003;overflow:hidden}.search-dialog::backdrop{background:#0007;backdrop-filter:blur(3px)}.search-top{display:flex;align-items:center;gap:15px;padding:19px 21px;border-bottom:1px solid var(--border)}#search-input{background:none;border:0;font-size:15px;width:100%;outline:none;min-width:0}#search-input:focus-visible{outline:none}#search-close{border:1px solid var(--border);background:var(--faint);color:var(--muted);font-size:10px;padding:5px 7px;border-radius:4px}.search-help{padding:11px 20px;font-size:9px;color:var(--muted);display:flex;justify-content:space-between;border-top:1px solid var(--border)}#search-results{padding:13px;max-height:56dvh;overflow:auto;min-height:95px}.search-result{display:block;padding:13px;border-radius:6px;margin-bottom:3px}.search-result:hover,.search-result.selected{background:var(--faint)}.search-result .result-group{display:block;font-size:9px;color:var(--muted);margin-bottom:5px}.search-result strong{display:block;font-size:13px;font-weight:500}.search-result p{font-size:11px;color:var(--muted);line-height:1.7;margin:7px 0 0}.search-message{padding:17px 12px;font-size:12px;color:var(--muted);line-height:1.8}.not-found{padding:55px 0 80px}.not-found>span{font-size:12px;color:var(--muted)}.not-found h1{font-size:33px;margin:22px 0;line-height:1.4}.not-found p{font-size:14px;color:var(--muted);margin-bottom:30px}
@media(min-width:1500px){.doc-layout{gap:80px;grid-template-columns:225px minmax(0,790px) 185px;padding:0 45px}}
@media(max-width:1200px){.doc-layout{grid-template-columns:200px minmax(0,1fr);gap:45px;padding:0 28px;max-width:1120px}.page-toc{display:none}.main-content{max-width:760px}.mobile-toc{display:block;border:1px solid var(--border);padding:12px 16px;border-radius:5px;margin-bottom:31px;font-size:11px;background:var(--faint)}.mobile-toc summary{cursor:pointer}.mobile-toc a{display:block;padding:8px 0;color:var(--muted)}.mobile-toc a:first-of-type{margin-top:9px}.docs-header{padding:0 28px;gap:20px}.search-open{margin-left:20px;width:230px}.header-nav{gap:21px}}
@media(max-width:900px){.doc-layout{grid-template-columns:185px minmax(0,1fr);gap:30px;padding:0 22px}.docs-header{padding:0 22px}.search-open{width:200px;gap:20px;margin-left:0}.header-nav{gap:17px}.guide-links{grid-template-columns:1fr}.article-heading h1{font-size:32px}.home-intro h1{font-size:38px}.sidebar .nav-group>a{font-size:11px}.sidebar .nav-group h2{font-size:11px}}
@media(max-width:760px){html{scroll-padding-top:85px}.docs-header{height:61px;padding:0 18px;gap:18px}.brand>span{font-size:24px}.brand-mark{width:21px;height:21px}.brand b{font-size:13px}.brand i{margin:0 5px;height:16px}.search-open{width:auto;border:0;padding:7px;margin-left:auto;background:none;font-size:11px}.search-open kbd{display:none}.search-open span{font-size:11px}.header-nav{margin-left:0;gap:13px}.header-nav>a:first-child{display:none}.trade-button{font-size:10px;padding:8px 10px}#theme-toggle{font-size:21px;width:21px}#menu-toggle{display:block}.doc-layout{display:block;padding:0 23px;max-width:760px}.sidebar{position:fixed;top:0;left:0;bottom:0;width:280px;max-width:85vw;background:var(--bg);z-index:50;height:100dvh;padding:22px 18px 28px;transform:translateX(-100%);transition:transform .2s ease;overflow:auto;border-right:1px solid var(--border)}.sidebar.open{transform:none}.sidebar-head{display:flex;align-items:center;justify-content:space-between;font-size:12px;margin:0 10px 25px}.sidebar-head button{font-size:24px;border:0;background:none;color:var(--muted);padding:0 5px}.sidebar .nav-group>a{font-size:12px;padding:10px 11px}.sidebar .nav-group h2{font-size:12px}.sidebar .nav-group{margin-bottom:26px}#sidebar-backdrop{position:fixed;inset:0;background:#0006;z-index:40}.main-content{padding-top:31px}.breadcrumb{margin-bottom:22px;font-size:10px}.article-heading h1{font-size:30px;line-height:1.4;letter-spacing:-.8px}.article-heading>p{font-size:13px}.article-meta{font-size:9px;margin-top:21px;padding-bottom:20px;margin-bottom:24px}.copy-page{font-size:9px}.prose{font-size:13px;line-height:1.95}.prose h2{font-size:20px}.prose>section{margin-bottom:32px}.prose p{margin:12px 0}.note{padding:16px 18px}.note p{font-size:11px}.formula{font-size:12px;padding:15px 17px}.mobile-toc{margin-bottom:27px}.heading-anchor{opacity:.45}.article-pagination{gap:11px}.article-pagination a{padding:14px}.article-pagination b{font-size:11px}.document-footer>div{flex-direction:column;gap:10px;font-size:9px}.document-footer p{font-size:9px}.home-intro h1{font-size:35px;letter-spacing:-1px}.home-intro p{font-size:13px;line-height:1.9}.home-intro p br{display:none}.home-note{margin:28px 0 33px;padding:17px 19px}.home-note p{font-size:11px}.guide-heading h2{font-size:22px}.guide-heading p{font-size:11px}.guide-links{grid-template-columns:1fr;gap:11px}.guide-links>a{padding:17px 19px}.guide-group{margin-bottom:33px}.home-end h2{font-size:20px}.calculator{padding:18px}.calculator-top{gap:18px}.calculator-top select{font-size:11px;max-width:180px;padding:8px}.calculator-top strong{font-size:21px}.calc-result span{font-size:11px}.caption{font-size:10px!important}.search-top{padding:17px}#search-input{font-size:13px}.not-found h1{font-size:27px}}
@media(max-width:400px){.brand i,.brand b{display:none}.header-nav{gap:9px}.docs-header{gap:12px;padding:0 16px}.doc-layout{padding:0 19px}.article-heading h1{font-size:27px}.home-intro h1{font-size:32px}.calculator-top{align-items:start}.calculator-top select{max-width:160px}.article-pagination{grid-template-columns:1fr}.article-pagination a:last-child{text-align:left}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}