:root{
  --bg:#FDFDFE;
  --bg-panel:#F3F5F9;
  --bg-panel-2:#E8ECF3;
  --panel-tint:#EAF0FB;
  --hero-top:#FFFFFF;
  --hero-bottom:#F1F4F9;
  --border:#DDE2EA;
  --accent:#1D4FF2;
  --accent-2:#4C7DFF;
  --accent-dark:#1238B8;
  --text:#0B0D12;
  --text-muted:#5A6170;
  --text-soft:#7A8191;
  --success:#138A4E;
  --warn:#B7791F;
  --error:#C9382D;
  --white:#FFFFFF;
  --white-a85:rgba(255,255,255,.85);
  --white-a72:rgba(255,255,255,.72);
  --white-a22:rgba(255,255,255,.22);
  --ink:#0F141F;
  --ink-2:#161C2A;
  --ink-line:rgba(255,255,255,.07);
  --ink-chip:rgba(255,255,255,.05);
  --ink-chip-2:rgba(255,255,255,.08);
  --ink-text:#E6EAF2;
  --ink-muted:#8A93A6;
  --ink-dot:#3A4355;
  --ink-shadow:rgba(15,20,31,.42);
  --accent-a06:rgba(29,79,242,.06);
  --accent-a10:rgba(29,79,242,.10);
  --accent-a18:rgba(29,79,242,.18);
  --accent-a38:rgba(29,79,242,.38);
  --accent-ink-glow:rgba(76,125,255,.14);
  --accent-ink-tint:rgba(76,125,255,.16);
  --accent-ink-text:#AFC3FF;
  --success-ink-tint:rgba(61,201,129,.14);
  --success-ink-on:rgba(61,201,129,.40);
  --success-ink-text:#86D9AE;
  --success-ink-dot:#4CC489;
  --grid-line:rgba(20,40,96,.04);
  --glow:rgba(29,79,242,.06);
  --hair:rgba(15,20,31,.04);
  --flag-red:#D8232F;
  --flag-white:#FFFFFF;
  --flag-navy:#24306E;
  --flag-navy-au:#0E2369;
  --flag-black:#16181D;
  --flag-gold:#F5C518;
  --flag-edge:rgba(11,13,18,.14);
  --veil:rgba(15,20,31,.42);
  --clear:transparent;
  --r-xs:4px;
  --r-sm:6px;
  --r-md:8px;
  --r-card:10px;
  --r-pill:999px;
  --r-round:50%;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --shell:1320px;
  --gutter:32px;
  --head-height:64px;
  --anchor-offset:88px;
  --toc-offset:88px;
  --chapter-offset:168px;
  --shadow-card:0 1px 2px var(--hair),0 20px 48px -6px var(--accent-a10),inset 0 0 0 1px var(--white-a85);
  --shadow-window:-14px 18px 36px -16px var(--ink-shadow),inset 0 0 0 1px var(--ink-line);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;font-family:var(--font-body);font-size:16px;line-height:1.6;color:var(--text);background-color:var(--bg);background-image:linear-gradient(var(--grid-line) 1px,var(--clear) 1px),linear-gradient(90deg,var(--grid-line) 1px,var(--clear) 1px);background-size:48px 48px;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img,svg{display:block;max-width:100%}
img{height:auto}
svg{flex-shrink:0}
button,a,summary{ -webkit-tap-highlight-color:var(--accent-a10)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
[hidden]{display:none!important}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);text-wrap:balance}
h1{font-size:clamp(52px,5vw,68px);font-weight:900;line-height:1.1;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:clamp(28px,3vw,40px);line-height:1.2;letter-spacing:-.02em;margin:0 0 24px}
h3{font-size:22px;line-height:1.35;margin:0 0 12px}
p{margin:0 0 20px}
ul,ol{padding-left:1.5em}
:where(main,article,section,div,li){min-width:0}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;border-radius:var(--r-md);background:var(--ink);color:var(--ink-text)}
pre code{overflow-wrap:normal;white-space:pre}
.no-break{white-space:nowrap}
.num{font-family:var(--font-mono);font-weight:500;letter-spacing:-.01em;font-variant-numeric:tabular-nums}
.shell,.wrap{width:100%;max-width:calc(var(--shell) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{max-width:880px;margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:80px;padding-bottom:80px}
.section-head{max-width:800px;margin-bottom:32px}
.section-head p,.muted{color:var(--text-muted)}
.text-link,.prose a{color:var(--accent);text-decoration:underline;text-underline-offset:4px}
.prose{overflow-wrap:anywhere}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.grid-three{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid-five{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:16px}
.panel,.card{padding:28px;background:var(--bg-panel);border-radius:var(--r-card);box-shadow:var(--shadow-card)}
.panel-inset{padding:20px;background:var(--bg-panel-2);border-radius:var(--r-md)}
.decor-zone{position:relative;overflow-x:clip;max-width:100%}
.decor-glow{position:absolute;inset:0 0 0 55%;background:radial-gradient(closest-side,var(--glow),var(--clear));pointer-events:none}
.svg-defs{position:absolute;width:0;height:0;overflow:hidden}
.skip{position:absolute;left:-10000px;top:8px;display:inline-flex;align-items:center;min-width:44px;min-height:44px;padding:8px 12px;white-space:nowrap;z-index:100;background:var(--white);color:var(--text);border-radius:var(--r-sm)}
.skip:focus{left:16px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 24px;border:1px solid var(--clear);border-radius:var(--r-md);font-size:16px;font-weight:600;font-family:var(--font-body);line-height:1.4;flex-shrink:0;white-space:nowrap;transition:transform .15s ease,box-shadow .15s ease}
.btn svg{width:16px;height:16px}
.btn-primary{color:var(--white);background:linear-gradient(135deg,var(--accent),var(--accent-2));box-shadow:0 12px 24px -10px var(--accent-a38),inset 0 1px 0 var(--white-a22)}
.btn-primary:hover{box-shadow:0 14px 28px -10px var(--accent-a38),inset 0 1px 0 var(--white-a22)}
.btn-primary:active{transform:translateY(1px)}
.btn-ghost,.btn-secondary{color:var(--text);background:var(--white);border-color:var(--border);box-shadow:0 1px 2px var(--hair)}
.btn-ghost:hover,.btn-secondary:hover{border-color:var(--text-soft)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none}
.btn-small{min-height:40px;padding:8px 16px;font-size:14px}
.cta-row{margin-top:22px;display:flex;justify-content:center;gap:12px;flex-wrap:wrap}
.statusbar{background:linear-gradient(90deg,var(--accent) 0%,var(--accent) 58%,var(--accent-2) 100%);color:var(--white);font-size:14px;font-weight:500;line-height:40px;min-height:40px;text-align:center}
.statusbar a{display:inline-flex;align-items:center;gap:8px}
.statusbar a:hover .statusbar-text{text-decoration:underline;text-underline-offset:3px}
.statusbar-sep{opacity:.6}
#site-header{position:relative;z-index:60}
.site-head{height:var(--head-height);background:var(--white-a85);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--border);position:relative;z-index:60}
.site-head .shell{height:100%;display:flex;align-items:center;gap:40px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;font-family:var(--font-display);font-weight:800;font-size:20px;letter-spacing:-.02em;color:var(--text);white-space:nowrap;flex-shrink:0;min-height:28px}
.brand img{width:28px;height:28px;flex-shrink:0}
.brand-zh{font-weight:500;color:var(--text-muted)}
.nav-main{display:flex;align-items:center;flex:1;min-width:0}
.nav-main>ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px}
.nav-link{display:inline-flex;align-items:center;gap:4px;min-height:36px;padding:6px 12px;border-radius:var(--r-sm);font-size:15px;font-weight:500;color:var(--text);background:var(--clear);border:0;font-family:var(--font-body);white-space:nowrap}
.nav-link:hover{background:var(--bg-panel)}
.nav-link[aria-current="page"],.nav-link.is-active{box-shadow:inset 0 -2px 0 var(--accent)}
.nav-link svg{width:12px;height:12px;color:var(--text-soft)}
.nav-more{position:relative}
.nav-drop{display:none;position:absolute;top:calc(100% + 8px);left:0;min-width:200px;margin:0;padding:6px;list-style:none;background:var(--white);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-card);z-index:70}
.nav-more.is-open .nav-drop{display:block}
.nav-drop a{display:flex;align-items:center;min-height:40px;padding:8px 12px;border-radius:var(--r-sm);font-size:14px}
.nav-drop a:hover{background:var(--bg-panel)}
.head-tools{margin-left:auto;display:flex;align-items:center;gap:8px;flex-shrink:0}
.lang-picker{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:36px;min-width:44px;width:auto;padding:6px 12px;border:0;background:var(--clear);border-radius:var(--r-sm);font-family:var(--font-body);font-size:14px;color:var(--text-muted)}
.lang:hover{background:var(--bg-panel)}
.lang svg{width:16px;height:16px}
.lang-text{white-space:nowrap}
.lang-panel{display:none;position:absolute;right:0;top:calc(100% + 10px);width:180px;padding:6px;background:var(--white);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-card);z-index:80}
.lang-picker.is-open .lang-panel{display:block}
.lang-panel a{display:flex;align-items:center;min-height:40px;padding:8px 12px;border-radius:var(--r-sm)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--bg-panel);color:var(--accent-dark)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:8px 18px;border-radius:var(--r-md);background:var(--text);color:var(--white);font-size:14px;font-weight:600;white-space:nowrap;box-shadow:inset 0 1px 0 var(--white-a22)}
.btn-login:hover{background:var(--ink)}
.menu-toggle{display:none;min-width:44px;min-height:44px;align-items:center;justify-content:center;flex-direction:column;gap:4px;border:1px solid var(--border);border-radius:var(--r-sm);background:var(--white);color:var(--text)}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{display:none}
.menu-veil{display:none}
html.nav-open{overflow:hidden}
.site-footer{padding-top:56px;padding-bottom:28px;background:var(--bg-panel);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:360px;margin-top:20px;color:var(--text-muted);font-size:14px}
.footer-title{font-size:14px;font-weight:700;margin:0 0 16px}
.footer-links{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px 16px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;font-size:14px}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px;padding-top:24px;border-top:1px solid var(--border)}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;margin-top:24px;font-size:13px;color:var(--text-muted)}
.footer-legal{display:flex;gap:20px;flex-wrap:wrap}
.reveal{transition:opacity .35s ease,transform .35s ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{display:block;position:static;min-width:0;width:100%;max-width:100%;min-height:80px;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}
@media(max-width:1180px){
  .site-head .shell{gap:24px}
  .nav-main>ul{gap:2px}
  .nav-link{padding-inline:9px}
}
@media(max-width:960px){
  .nav-main{display:none}
  .head-tools{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .site-head .shell{gap:16px}
  .mobile-drawer{position:fixed;inset:var(--drawer-top,var(--head-height)) 0 auto;z-index:55;height:calc(100dvh - var(--drawer-top,var(--head-height)));max-height:calc(100dvh - var(--drawer-top,var(--head-height)));padding:20px var(--gutter) 32px;background:var(--white);overflow-y:auto;overscroll-behavior:contain;border-top:1px solid var(--border)}
  .mobile-drawer.is-open{display:block}
  .mobile-drawer ul{list-style:none;padding:0;margin:0}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 14px;border-radius:var(--r-sm)}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current]{background:var(--bg-panel);color:var(--accent-dark)}
  .drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
  .menu-veil{position:fixed;inset:var(--drawer-top,var(--head-height)) 0 0;background:var(--veil);z-index:50;border:0}
  .menu-veil.is-open{display:block}
  .grid-five{grid-template-columns:repeat(3,minmax(0,1fr))}
  .footer-grid{gap:28px}
}
@media(max-width:768px){
  :root{--gutter:20px}
  h1{font-size:36px;line-height:1.12}
  h2{font-size:28px}
  .section{padding-top:48px;padding-bottom:48px}
  .grid-three{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .statusbar{font-size:12px;line-height:1.5;padding:9px 16px}
  .statusbar a{justify-content:center;flex-wrap:wrap;gap:4px}
  .lang-text{display:none}
  .lang{padding-inline:8px}
  .footer-grid{grid-template-columns:1fr}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.tilt-decor{transform:none}
  .decor-zone,.decor-glow{max-width:100%}
  .panel,.card{padding:22px}
  .site-head .shell{gap:8px}
  .head-tools{gap:4px;margin-left:auto}
  .brand{font-size:18px;gap:7px}
  .brand img{width:26px;height:26px}
  .btn-login{padding-inline:12px}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .brand{font-size:16px;gap:5px}
  .brand img{width:24px;height:24px}
  .head-tools{gap:2px}
  .btn-login{padding-inline:10px}
  .grid-five{grid-template-columns:1fr}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}