:root{
  --bg:#F9F0DF;
  --bg-hero-top:#FCF6EA;
  --bg-hero-bottom:#F2E7D2;
  --panel:#FFFBF3;
  --panel-2:#F0E5CF;
  --border:#E2D4B8;
  --border-strong:#CDBC9B;
  --accent:#2F4FD9;
  --accent-2:#5A74F0;
  --accent-dark:#1F37A8;
  --text:#2A2016;
  --muted:#6E604E;
  --on-accent:#FFFFFF;
  --success:#2E8A4F;
  --warn:#C28414;
  --error:#C0392B;
  --accent-06:rgba(47,79,217,.06);
  --accent-12:rgba(47,79,217,.12);
  --accent-50:rgba(47,79,217,.5);
  --white-16:rgba(255,255,255,.16);
  --white-24:rgba(255,255,255,.24);
  --white-70:rgba(255,255,255,.7);
  --ink-06:rgba(42,32,22,.06);
  --ink-10:rgba(42,32,22,.1);
  --veil-color:rgba(42,32,22,.3);
  --flag-red:#C8312E;
  --flag-blue:#2B3F86;
  --flag-white:#FFFDF8;
  --flag-ring:rgba(42,32,22,.16);
  --clear:transparent;
  --mask-ink:#000000;
  --shadow-win:0 40px 80px -30px rgba(47,79,217,.20),0 14px 36px -18px rgba(47,79,217,.12);
  --shadow-card:0 18px 40px -20px rgba(47,79,217,.18),0 1px 2px rgba(42,32,22,.04);
  --shadow-float:0 30px 60px -22px rgba(47,79,217,.28),0 6px 16px -8px rgba(47,79,217,.12);
  --shadow-cta:0 12px 26px -12px rgba(47,79,217,.55),inset 0 1px 0 rgba(255,255,255,.18);
  --inset-sunk:inset 0 2px 6px rgba(42,32,22,.05),inset 0 0 0 1px rgba(226,212,184,.7);
  --radius-s:8px;
  --radius-m:10px;
  --radius-l:16px;
  --radius-xs:6px;
  --radius-focus:4px;
  --radius-pill:999px;
  --radius-circle:50%;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --size-body:16px;
  --size-small:14px;
  --size-h1:68px;
  --size-h2:38px;
  --size-h3:22px;
  --weight-normal:400;
  --weight-medium:500;
  --weight-semibold:600;
  --weight-bold:700;
  --weight-brand:800;
  --weight-display:900;
  --tracking-display:-.03em;
  --tracking-cjk:-.02em;
  --leading-body:1.6;
  --leading-heading:1.2;
  --gutter:40px;
  --header-height:76px;
  --anchor-offset:92px;
  --toc-offset:152px;
  --section-space:80px;
  --duration-fast:.16s;
  --duration-reveal:.35s;
  --mask-fade:linear-gradient(to bottom,var(--mask-ink) 70%,var(--clear) 100%);
  --grain:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .165 0 0 0 0 .125 0 0 0 0 .086 0 0 0 .9 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  --grain-opacity:.03;
}
*,*::before,*::after{box-sizing:border-box}
*{margin:0;padding:0}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-offset)}
body{font-family:var(--font-body);font-size:var(--size-body);font-weight:var(--weight-normal);color:var(--text);background:var(--bg);line-height:var(--leading-body);min-width:320px;-webkit-font-smoothing:antialiased}
body::after{content:"";position:fixed;inset:0;background-image:var(--grain);opacity:var(--grain-opacity);pointer-events:none;z-index:90}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
button:disabled{cursor:not-allowed}
img{display:block;max-width:100%;height:auto}
svg{display:block;flex-shrink:0}
ul{list-style:none}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:var(--weight-display);line-height:var(--leading-heading);overflow-wrap:break-word}
h1{font-size:clamp(52px,5vw,72px);letter-spacing:var(--tracking-display)}
h2{font-size:var(--size-h2);letter-spacing:var(--tracking-cjk)}
h3{font-size:var(--size-h3);letter-spacing:var(--tracking-cjk)}
p{overflow-wrap:break-word}
strong{font-weight:var(--weight-semibold)}
code{font-family:var(--font-mono);overflow-wrap:anywhere;font-size:.9em}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:24px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--radius-s)}
pre code{white-space:pre;overflow-wrap:normal}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--radius-focus)}
[hidden]{display:none!important}
.no-break{white-space:nowrap}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:16px;top:-60px;z-index:100;padding:8px 14px;background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-s);font-size:var(--size-small)}
.skip:focus{top:12px}
.wrap{width:100%;max-width:1320px;margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.section-head{max-width:760px;margin-bottom:40px}
.section-head p{margin-top:16px;color:var(--muted);font-size:18px}
.grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid-5{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:16px}
.grid-3>*,.grid-5>*,.wrap>*,main,article,section{min-width:0}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-m);box-shadow:var(--shadow-card);padding:28px}
.sunk{background:var(--panel-2);box-shadow:var(--inset-sunk)}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:12px 28px;font-size:16px;font-weight:var(--weight-semibold);letter-spacing:.01em;border-radius:var(--radius-s);transition:background-color var(--duration-fast) ease,color var(--duration-fast) ease;flex-shrink:0;white-space:nowrap;text-align:center}
.btn-main,.btn-primary{background:var(--accent);color:var(--on-accent);box-shadow:var(--shadow-cta)}
.btn-main:hover,.btn-primary:hover{background:var(--accent-dark)}
.btn-ghost,.btn-secondary{background:var(--panel);color:var(--text);border:1.5px solid var(--text)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--panel-2)}
.btn:active{box-shadow:var(--inset-sunk)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--panel-2);color:var(--muted);box-shadow:none;border:1px solid var(--border-strong);pointer-events:none}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:32px}
.topbar,#site-header{position:relative;z-index:50}
.topbar-in{display:flex;align-items:center;flex-wrap:nowrap;height:var(--header-height);gap:0}
.brand{display:inline-flex;align-items:center;gap:10px;flex-shrink:0}
.brand img{width:34px;height:34px}
.brand-word{font-family:var(--font-display);font-weight:var(--weight-brand);font-size:21px;letter-spacing:var(--tracking-cjk);color:var(--text)}
.brand-zh{font-size:16px;font-weight:var(--weight-medium);color:var(--muted)}
.nav{display:flex;align-items:center;flex:1;min-width:0;margin-left:52px}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px}
.nav-link,.nav-more-btn{position:relative;display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:40px;padding:8px 13px;font-size:15px;font-weight:var(--weight-medium);color:var(--text);border-radius:var(--radius-s);white-space:nowrap}
.nav-link:hover,.nav-more-btn:hover{background:var(--ink-06)}
.nav a[aria-current="page"]{font-weight:var(--weight-bold)}
.nav-link[aria-current="page"]::after{content:"";position:absolute;left:13px;right:13px;bottom:4px;height:2px;border-radius:var(--radius-focus);background:var(--text)}
.caret{font-size:11px;color:var(--muted)}
.nav-more{position:relative}
.nav-menu{position:absolute;top:calc(100% + 6px);left:0;min-width:200px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-m);box-shadow:var(--shadow-card);display:none;z-index:65}
.nav-more.is-open>.nav-menu,.nav-more:focus-within>.nav-menu,.nav-more:hover>.nav-menu{display:block}
.menu-group+.menu-group{margin-top:6px;padding-top:6px;border-top:1px solid var(--border)}
.menu-label{display:block;padding:4px 10px;font:var(--weight-medium) 11px/1.4 var(--font-mono);color:var(--muted);letter-spacing:.04em}
.menu-link{display:flex;align-items:center;min-height:40px;padding:8px 10px;font-size:14px;border-radius:var(--radius-xs)}
.menu-link:hover{background:var(--panel-2)}
.top-tools{margin-left:auto;display:flex;align-items:center;gap:10px;flex-shrink:0}
.lang-picker{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:40px;min-width:44px;width:auto;padding:8px 12px;font-size:14px;color:var(--muted);border-radius:var(--radius-s);white-space:nowrap}
.lang span{white-space:nowrap}
.lang:hover{background:var(--ink-06);color:var(--text)}
.lang-panel{display:none;position:absolute;right:0;top:calc(100% + 8px);z-index:70;min-width:180px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-m);box-shadow:var(--shadow-card)}
.lang-picker.is-open>.lang-panel{display:block}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--radius-xs)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--panel-2)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:8px 20px;font-size:15px;font-weight:var(--weight-semibold);color:var(--text);background:var(--panel);border:1.5px solid var(--text);border-radius:var(--radius-s);white-space:nowrap}
.login:hover{background:var(--text);color:var(--panel)}
.burger{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--radius-s)}
.burger svg{width:22px;height:22px}
.mobile-drawer{display:none;position:fixed;top:var(--header-height);right:0;left:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);padding:16px var(--gutter) 32px;z-index:49}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-bottom:1px solid var(--border);border-radius:var(--radius-xs)}
.mobile-drawer a[aria-current="page"],.mobile-drawer a:hover{background:var(--panel-2)}
.drawer-label{padding:24px 16px 8px;color:var(--muted);font-size:13px}
.nav-veil{display:none;position:fixed;inset:var(--header-height) 0 0;background:var(--veil-color);z-index:48}
html.nav-open{overflow:hidden}
.site-footer{border-top:1px solid var(--border);padding-top:64px;padding-bottom:24px;background:var(--panel-2)}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:48px}
.footer-brand p{margin-top:20px;max-width:360px;color:var(--muted);font-size:14px}
.footer-title{font-size:15px;font-weight:var(--weight-bold);margin-bottom:12px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 20px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;font-size:14px}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{text-decoration:underline;text-underline-offset:4px}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:40px;padding-top:24px;border-top:1px solid var(--border-strong)}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;margin-top:24px;color:var(--muted);font-size:13px}
.footer-legal{display:flex;flex-wrap:wrap;gap:8px 20px}
.reveal{transition:opacity var(--duration-reveal) ease,transform var(--duration-reveal) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:120px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}
.prose{max-width:820px}
.prose p,.prose ul,.prose ol,.prose pre,.prose blockquote{margin-block:20px}
.prose h2{margin-top:48px;margin-bottom:20px}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose li+li{margin-top:8px}
.prose a{text-decoration:underline;text-underline-offset:4px}
.prose section[id]{scroll-margin-top:var(--anchor-offset)}
body:has(.toc-tabs) section[id]{scroll-margin-top:var(--toc-offset)}
@media(min-width:1600px){.wrap{max-width:1320px}}
@media(max-width:1180px){.nav{margin-left:24px}.nav-link,.nav-more-btn{padding-inline:10px}}
@media(max-width:1000px){
  .nav{display:none}
  .burger{display:inline-flex}
  .top-tools{margin-left:auto}
  html.nav-open .mobile-drawer{display:block}
  html.nav-open .nav-veil{display:block}
  .footer-grid{grid-template-columns:1.2fr 1fr;gap:32px}
  .footer-brand{grid-column:1/-1}
  .grid-5{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media(min-width:1001px){html.nav-open{overflow:auto}}
@media(max-width:768px){
  :root{--gutter:20px;--section-space:56px}
  h1{font-size:clamp(28px,7vw,40px);letter-spacing:var(--tracking-cjk)}
  h2{font-size:30px}
  .grid-3{grid-template-columns:minmax(0,1fr)}
  .grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.float-card{transform:none}
  .top-tools{gap:6px;margin-left:auto}
  .top-tools .lang-picker{display:none}
  .brand-word{font-size:19px}
  .brand{gap:7px}
  .brand img{width:30px;height:30px}
  .login{padding-inline:14px;font-size:14px}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-brand{grid-column:auto}
  .panel,.card{padding:20px}
  .btn{padding-inline:22px}
  .cta-row .btn{flex:1 1 140px}
  .footer-bottom{align-items:flex-start;flex-direction:column}
  .section-head p{font-size:16px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  .btn,.nav-menu{transition:none}
}