:root{
  --bg:#FAFBFC;--panel:#FFFFFF;--panel-2:#EEF2F8;--border:#DCE3EE;
  --accent:#1764F4;--accent-2:#5AA0FF;--accent-dark:#0B2E66;
  --accent-soft:#E9F1FE;--accent-soft-2:#D7E5FD;--accent-line:#BCD3FB;
  --text:#0E2244;--muted:#5A6B86;--success:#16A06A;--warn:#E8A317;--error:#D93A3A;
  --magenta:#D94BF5;--violet:#9B5CFF;--on-dark:#FFFFFF;
  --flag-red:#D8323C;--flag-blue:#1F3F8F;--flag-navy:#13286E;--flag-white:#FFFFFF;
  --accent-rgb:23,100,244;--sky-rgb:90,160,255;--navy-rgb:11,46,102;--white-rgb:255,255,255;--success-rgb:22,160,106;
  --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','Hiragino Sans GB','Microsoft YaHei',system-ui,-apple-system,'Segoe UI',sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --weight-normal:400;--weight-medium:500;--weight-semibold:600;--weight-bold:700;--weight-display:800;
  --r-xl:24px;--r-lg:16px;--r-md:12px;--r-sm:8px;--r-pill:999px;--r-round:50%;
  --shadow-1:0 8px 22px -10px rgba(var(--accent-rgb),.14);
  --shadow-2:0 34px 80px -20px rgba(var(--accent-rgb),.12),0 10px 24px -14px rgba(var(--navy-rgb),.10);
  --shadow-3:0 18px 38px -10px rgba(var(--accent-rgb),.22),0 3px 8px rgba(var(--navy-rgb),.06);
  --gutter:48px;--content-width:1440px;--reading-width:840px;
  --head-height:68px;--drawer-top:108px;--anchor-offset:88px;--toc-offset:88px;--section-anchor:164px;
  --ease-out:cubic-bezier(.2,.7,.2,1);--time-fast:.2s;--time-reveal:.35s;
  --text-xs:12px;--text-sm:14px;--text-base:16px;--text-lead:20px;
  --title-lg:clamp(52px,4.31vw,62px);--title-md:34px;--title-sm:22px;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-base);line-height:1.6;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img{max-width:100%;height:auto}
svg{flex-shrink:0;vertical-align:middle}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,a,summary{touch-action:manipulation}
button{color:inherit}
h1,h2,h3,h4,p,figure,blockquote{margin:0}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--accent-dark);font-weight:var(--weight-display);text-wrap:balance}
h1{font-size:var(--title-lg);line-height:1.1;letter-spacing:-.02em}
h2{font-size:var(--title-md);line-height:1.25;letter-spacing:-.02em}
h3{font-size:var(--title-sm);line-height:1.35}
ul{list-style:none;margin:0;padding:0}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-sm)}
::selection{background:var(--accent-soft-2);color:var(--accent-dark)}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading-width);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:72px;padding-bottom:72px}
.section-head{max-width:760px;margin-bottom:32px}
.section-head p{margin-top:16px;color:var(--muted)}
.no-break{white-space:nowrap}
.mono{font-family:var(--font-mono);letter-spacing:-.02em;font-variant-numeric:tabular-nums}
.muted{color:var(--muted)}
.accent{color:var(--accent)}
.lead{font-size:var(--text-lead);line-height:1.65}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-5{grid-template-columns:repeat(5,minmax(0,1fr))}
.flex-row{display:flex;align-items:center;flex-wrap:wrap;gap:12px}
.panel,.card{min-width:0;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-xl);box-shadow:var(--shadow-1),inset 0 1px 0 var(--panel);padding:24px}
.panel-sunken{background:var(--panel-2);box-shadow:none}
.prose{min-width:0;overflow-wrap:break-word}
.prose p,.prose ul,.prose ol,.prose blockquote,.prose pre{margin-block:20px}
.prose h2{margin-top:48px;margin-bottom:20px}
.prose h3{margin-top:28px;margin-bottom:12px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose a{text-decoration:underline;text-underline-offset:3px;color:var(--accent)}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere;background:var(--panel-2);border-radius:var(--r-sm);padding:2px 5px}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:20px;border:1px solid var(--border);border-radius:var(--r-md);background:var(--panel-2)}
pre code{padding:0;white-space:pre;overflow-wrap:normal}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:46px;min-width:24px;padding:10px 22px;border:1px solid var(--border);border-radius:var(--r-md);font-weight:var(--weight-bold);font-size:var(--text-sm);line-height:1.5;transition:background var(--time-fast),box-shadow var(--time-fast),transform var(--time-fast);text-align:center}
.btn svg{width:20px;height:20px}
.btn-primary{background:var(--accent);color:var(--on-dark);border-color:var(--accent);box-shadow:var(--shadow-1)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent-dark);border-color:var(--accent-dark);box-shadow:var(--shadow-3)}
.btn-secondary{background:var(--accent-dark);color:var(--on-dark);border-color:var(--accent-dark)}
.btn-secondary:hover{background:var(--accent)}
.btn-outline{background:var(--panel);border-color:var(--accent-dark);color:var(--accent-dark)}
.btn-outline:hover{background:var(--accent-soft)}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--panel-2);color:var(--muted);border-color:var(--border);box-shadow:none;cursor:not-allowed}
.btn.is-focus{outline:2px solid var(--accent);outline-offset:3px}
.reveal{transition:opacity var(--time-reveal) var(--ease-out),transform var(--time-reveal) var(--ease-out)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;min-width:0;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:24px}
#server-status>*{min-width:0;max-width:100%}
.ann-toggle{position:absolute;width:1px;height:1px;opacity:0;pointer-events:none}
.ann-toggle:checked+.announce{display:none}
.ann-toggle:focus-visible+.announce .announce-x{outline:2px solid var(--accent-2);outline-offset:2px}
.announce{position:relative;background:var(--accent-dark);color:var(--on-dark)}
.announce-in{height:40px;display:flex;align-items:center;justify-content:center;gap:20px;padding:0 64px}
.announce-text{font-size:14px;font-weight:var(--weight-medium);letter-spacing:.01em}
.announce-pill{flex:none;display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:26px;padding:0 13px;border-radius:var(--r-pill);background:var(--accent-soft-2);color:var(--accent-dark);font-size:13px;font-weight:var(--weight-bold)}
.announce-pill:hover{background:var(--panel)}
.announce-x{position:absolute;right:20px;top:50%;width:28px;height:28px;margin-top:-14px;display:grid;place-items:center;border:0;padding:0;border-radius:var(--r-pill);background:none;color:var(--on-dark);cursor:pointer}
.announce-x:hover{background:rgba(var(--white-rgb),.14)}
.announce-x svg{width:16px;height:16px}
#site-header{position:relative;z-index:60}
.site-head{position:relative;z-index:3;background:rgba(var(--white-rgb),.9);-webkit-backdrop-filter:saturate(1.4) blur(10px);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--border)}
.head-in{min-height:var(--head-height);display:flex;align-items:center;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;font-family:var(--font-display);font-weight:var(--weight-display);font-size:21px;letter-spacing:-.025em;color:var(--accent-dark);white-space:nowrap;flex-shrink:0}
.brand img{width:34px;height:34px;flex:none}
.brand-zh{font-size:var(--text-sm);font-weight:var(--weight-medium);color:var(--muted)}
.nav{margin-left:52px;flex:1;min-width:0}
.nav-list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px;flex-wrap:nowrap}
.nav-link{position:relative;display:inline-flex;align-items:center;justify-content:center;gap:5px;height:40px;padding:0 14px;border:0;border-radius:var(--r-sm);background:none;color:var(--text);font-size:15px;font-weight:var(--weight-semibold);white-space:nowrap}
.nav-link:hover{background:var(--panel-2)}
.nav-link.is-current{color:var(--accent)}
.nav-link.is-current::after{content:"";position:absolute;left:14px;right:14px;bottom:4px;height:2px;border-radius:var(--r-pill);background:var(--accent)}
.nav-more{position:relative}
.nav-more>summary{list-style:none}
.nav-more>summary::-webkit-details-marker{display:none}
.nav-drop{position:absolute;z-index:5;top:calc(100% + 10px);left:0;min-width:252px;padding:10px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-lg);box-shadow:var(--shadow-3)}
.nav-more:not([open])>.nav-drop{display:none}
.drop-group{padding:6px 10px 4px;font-size:12px;font-weight:var(--weight-bold);letter-spacing:.06em;color:var(--muted)}
.drop-link{display:flex;flex-direction:column;padding:8px 10px;min-height:44px;border-radius:var(--r-sm)}
.drop-link:hover,.drop-link.is-current{background:var(--accent-soft)}
.drop-link b{font-size:14px;font-weight:var(--weight-bold);color:var(--accent-dark)}
.drop-link span{font-size:12px;line-height:1.5;color:var(--muted)}
.drop-link+.drop-group{margin-top:6px;border-top:1px solid var(--border);padding-top:10px}
.head-actions{display:flex;align-items:center;gap:10px;margin-left:auto;flex-shrink:0}
.language{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;width:auto;min-width:44px;height:40px;padding:0 12px;border:0;background:none;border-radius:var(--r-sm);font-size:14px;font-weight:var(--weight-semibold);color:var(--muted)}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px}
.lang:hover{background:var(--panel-2)}
.lang-panel{position:absolute;z-index:10;right:0;top:calc(100% + 12px);width:188px;padding:8px;border:1px solid var(--border);border-radius:var(--r-lg);background:var(--panel);box-shadow:var(--shadow-3)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-sm)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--accent-soft);color:var(--accent)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:42px;padding:0 22px;border:1.5px solid var(--accent-dark);border-radius:var(--r-md);background:var(--panel);color:var(--accent-dark);font-size:15px;font-weight:var(--weight-bold);white-space:nowrap}
.login:hover{background:var(--accent-dark);color:var(--on-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--r-sm);background:var(--panel);color:var(--accent-dark)}
.menu-toggle svg{width:22px;height:22px}
.mobile-drawer{position:fixed;z-index:2;top:var(--drawer-top);right:0;left:0;height:calc(100dvh - var(--drawer-top));max-height:calc(100dvh - var(--drawer-top));overflow-y:auto;overscroll-behavior:contain;padding:16px var(--gutter) 32px;background:var(--panel);border-top:1px solid var(--border)}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 14px;border-radius:var(--r-sm);color:var(--accent-dark);font-weight:var(--weight-semibold)}
.mobile-drawer a:hover,.mobile-drawer a.is-current,.mobile-drawer a[aria-current]{background:var(--accent-soft);color:var(--accent)}
.drawer-languages{margin-top:16px;padding-top:16px;border-top:1px solid var(--border)}
.drawer-label{padding:8px 14px;font-size:var(--text-xs);color:var(--muted)}
.nav-veil{position:fixed;z-index:1;inset:var(--drawer-top) 0 0;background:rgba(var(--navy-rgb),.22);border:0}
html.nav-open{overflow:hidden}
.site-foot{margin-top:48px;padding-top:56px;background:var(--panel-2);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:36px;padding-bottom:40px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:16px;max-width:330px;color:var(--muted);font-size:var(--text-sm)}
.footer-title{font-size:var(--text-sm);margin-bottom:12px;color:var(--accent-dark);font-weight:var(--weight-bold)}
.footer-links{display:grid;gap:4px}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--text-sm);color:var(--muted);overflow-wrap:anywhere}
.footer-links a:hover{color:var(--accent)}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;padding-top:20px;padding-bottom:24px;border-top:1px solid var(--border);font-size:var(--text-xs);color:var(--muted)}
.footer-legal{display:flex;align-items:center;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px}
@media(max-width:1320px){
  :root{--gutter:40px}
  .nav{margin-left:32px}
  .nav-link{padding-inline:11px}
  .nav-link.is-current::after{left:11px;right:11px}
}
@media(max-width:1100px){
  .nav{display:none}
  .head-actions{margin-left:auto}
  .menu-toggle{display:inline-flex}
}
@media(min-width:1101px){
  .mobile-drawer,.nav-veil{display:none!important}
}
@media(max-width:768px){
  :root{--gutter:20px;--title-lg:36px;--title-md:26px;--title-sm:20px}
  .section{padding-top:48px;padding-bottom:48px}
  .announce-in{justify-content:flex-start;gap:10px;padding:8px 48px 8px 16px;height:auto;min-height:40px}
  .announce-text{font-size:12.5px;line-height:1.5}
  .announce-x{right:10px}
  .lang span{display:none}
  .lang{padding-inline:8px}
  .login{padding-inline:16px}
  .grid-3{grid-template-columns:minmax(0,1fr)}
  .grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:28px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.tilted,.float-mail{transform:none}
  .decoration,.stripe-halo{max-width:100%}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:380px){
  :root{--gutter:16px}
  .brand{font-size:17px;gap:6px}
  .brand img{width:28px;height:28px}
  .head-actions{gap:4px}
  .login{padding-inline:10px;font-size:13px}
  .lang{min-width:36px;padding-inline:6px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}