:root{
  color-scheme:light;
  --bg:#F6F8FB;
  --panel:#FFFFFF;
  --panel-2:#EDF2F8;
  --border:#DCE4EE;
  --accent:#E62E8C;
  --accent-dark:#B5156A;
  --text:#0E1320;
  --muted:#5A6475;
  --success:#13A35A;
  --warn:#D98A0B;
  --error:#D63031;
  --sky-top:#C4E0FC;
  --sky-mid:#E6F2FE;
  --sky-deep:#8EC4F6;
  --navy:#123063;
  --silver-hi:#E9EEF5;
  --silver-lo:#C9D3E0;
  --silver-edge:#B3BFCF;
  --lavender:#DADEF6;
  --pink-soft:#FCE4F1;
  --glass:rgba(255,255,255,.7);
  --glass-strong:rgba(255,255,255,.88);
  --hi-line:rgba(255,255,255,.92);
  --cloud:rgba(255,255,255,.95);
  --cloud-soft:rgba(255,255,255,.55);
  --cloud-fade:rgba(255,255,255,0);
  --success-soft:rgba(19,163,90,.12);
  --accent-10:rgba(230,46,140,.10);
  --accent-08:rgba(230,46,140,.08);
  --sky-12:rgba(70,150,230,.12);
  --sky-22:rgba(70,150,230,.22);
  --ink-06:rgba(14,19,32,.06);
  --ink-10:rgba(14,19,32,.10);
  --ink-16:rgba(14,19,32,.16);
  --veil:rgba(14,19,32,.3);
  --clear:transparent;
  --flag-red:#D9293C;
  --flag-navy:#22336B;
  --flag-green:#159257;
  --flag-white:#FFFFFF;
  --shadow-tint:0 22px 48px var(--accent-10),0 14px 48px var(--sky-12);
  --shadow-float:0 16px 36px var(--sky-22),0 8px 22px var(--accent-08),inset 0 0 0 1px var(--hi-line);
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --r-xl:28px;
  --r-lg:24px;
  --r-md:16px;
  --r-sm:11px;
  --r-xs:5px;
  --r-flag:4px;
  --r-tile:13px;
  --r-line:14px;
  --r-screen:20px;
  --r-stand:30px;
  --r-nav:10px;
  --r-notch:8px;
  --r-base:3px 3px 18px 18px;
  --r-pill:999px;
  --r-circle:50%;
  --gutter:24px;
  --wrap-width:1200px;
  --header-height:68px;
  --anchor-offset:84px;
  --toc-offset:148px;
  --ease:cubic-bezier(.2,.7,.2,1);
  --fast:.2s;
  --reveal-time:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:var(--anchor-offset);-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
html.nav-open{overflow:hidden}
[hidden]{display:none!important}
a{color:inherit;text-underline-offset:.2em}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
button svg,a svg{flex-shrink:0}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:clamp(52px,5vw,68px);font-weight:800;line-height:1.1;letter-spacing:-.02em}
h2{font-size:clamp(28px,3.4vw,40px);font-weight:800;line-height:1.2;letter-spacing:-.02em}
h3{font-size:24px;line-height:1.3}
p{margin:0 0 1.25em}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;border-radius:var(--r-md);background:var(--panel-2);color:var(--text)}
pre code{overflow-wrap:normal;white-space:pre}
table{border-collapse:collapse}
th,td{word-break:keep-all}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
.wrap{width:100%;max-width:var(--wrap-width);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:64px;padding-bottom:64px;position:relative;overflow-x:clip}
.section-head{text-align:center;max-width:800px;margin:0 auto 32px}
.section-head h2{margin:12px 0}
.section-head p{color:var(--muted)}
.reading-wrap{max-width:840px;margin-inline:auto}
.prose{min-width:0;overflow-wrap:break-word}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:2em}
.prose h3{margin-top:1.6em}
.prose img{border-radius:var(--r-md)}
.prose a{color:var(--accent-dark)}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid>*{min-width:0}
.panel,.card{min-width:0;padding:28px;border-radius:var(--r-xl);background:var(--panel);box-shadow:var(--shadow-tint),inset 0 0 0 1px var(--hi-line)}
.panel-inset{padding:24px;background:var(--panel-2);border-radius:var(--r-lg)}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.icon{display:inline-block;width:20px;height:20px;vertical-align:middle;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:10px 30px;border:0;border-radius:var(--r-pill);font-size:17px;font-weight:600;line-height:1.4;text-decoration:none;transition:transform var(--fast),box-shadow var(--fast);flex-shrink:0;white-space:nowrap}
.btn svg{width:18px;height:18px}
.btn-primary{background:var(--text);color:var(--panel);box-shadow:0 12px 26px var(--ink-16)}
.btn-ghost,.btn-secondary{background:var(--panel);color:var(--text);box-shadow:inset 0 0 0 1.5px var(--text)}
.btn:hover,.btn.is-hover{transform:translateY(-1px);box-shadow:var(--shadow-tint)}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;pointer-events:none}
.btn-small{min-height:40px;padding:8px 20px;font-size:14px}
.cta-row{display:flex;flex-wrap:wrap;justify-content:center;gap:14px;margin-bottom:16px}
.badge,.tag{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:26px;padding:3px 10px;border-radius:var(--r-pill);background:var(--panel-2);color:var(--text);font-size:12px;font-weight:600;max-width:100%;overflow-wrap:anywhere}
.badge-success{background:var(--success-soft);color:var(--success)}
.badge-accent{background:var(--pink-soft);color:var(--accent-dark)}
.eyebrow{margin:0;font:600 13px/1.3 var(--font-mono);letter-spacing:.06em;color:var(--muted)}
.eyebrow b{margin-right:8px;color:var(--accent)}
.dot{display:inline-block;width:6px;height:6px;border-radius:var(--r-circle);flex:none}
#server-status{display:block;position:relative;min-width:0;max-width:100%;min-height:120px;overflow:hidden;margin-block:24px 32px}
#server-status+*{margin-top:24px}
.reveal{transition:opacity var(--reveal-time) ease,transform var(--reveal-time) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}

/* Shared top bar. Fixed drawers have no filtered ancestor. */
#site-header{position:relative;z-index:50;min-height:var(--header-height)}
body:has(.hero) #site-header{position:absolute;inset:0 0 auto;min-height:var(--header-height)}
.topbar{position:absolute;top:0;left:0;right:0;z-index:50}
.topbar-in{max-width:1360px;height:var(--header-height);margin:0 auto;padding:0 40px;display:flex;flex-wrap:nowrap;align-items:center;gap:20px}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex:none;min-height:32px}
.brand img{display:block;width:32px;height:32px;flex:none}
.brand-en{font:800 19px/1 var(--font-display);letter-spacing:-.02em;white-space:nowrap}
.brand-zh{font-size:13px;font-weight:500;color:var(--muted);line-height:1;white-space:nowrap}
.nav{flex:1;display:flex;justify-content:center;min-width:0}
.nav ul{display:flex;align-items:center;gap:8px;list-style:none;margin:0;padding:0}
.nav a{display:flex;align-items:center;justify-content:center;gap:6px;min-height:36px;padding:0 11px;border-radius:var(--r-pill);font-size:14px;font-weight:500;color:var(--text);text-decoration:none;white-space:nowrap;transition:background-color var(--fast)}
.nav a svg{width:16px;height:16px;flex:none;color:var(--muted)}
.nav a:hover{background:var(--glass)}
.nav a[aria-current="page"]{background:var(--glass);box-shadow:inset 0 0 0 1px var(--hi-line);font-weight:600}
.nav a[aria-current="page"] svg{color:var(--text)}
.tools{display:flex;align-items:center;gap:8px;flex:none}
.tools::before{content:"";width:1px;height:18px;background:var(--ink-16);margin-right:6px}
.language-picker{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;min-height:36px;padding:0 12px;border:0;border-radius:var(--r-pill);background:var(--clear);font:500 14px/1 var(--font-body);color:var(--text);cursor:pointer;white-space:nowrap}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px;color:var(--muted)}
.lang:hover{background:var(--glass)}
.language-panel{position:absolute;right:0;top:calc(100% + 12px);z-index:80;min-width:180px;padding:8px;background:var(--panel);border-radius:var(--r-md);box-shadow:var(--shadow-tint),inset 0 0 0 1px var(--border)}
.language-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-sm);text-decoration:none;font-size:14px}
.language-panel a:hover,.language-panel a[aria-current="true"]{background:var(--panel-2)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:6px 22px;border-radius:var(--r-pill);background:var(--text);color:var(--panel);font-size:14px;font-weight:600;text-decoration:none;transition:transform var(--fast);white-space:nowrap}
.login:hover{transform:translateY(-1px)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:0;border-radius:var(--r-pill);background:var(--clear);color:var(--text)}
.menu-toggle svg{width:22px;height:22px}
.menu-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));padding:16px var(--gutter) 32px;overflow-y:auto;overscroll-behavior:contain;background:var(--panel);z-index:62}
.menu-drawer a{display:flex;align-items:center;gap:12px;width:100%;min-height:44px;padding:12px 16px;text-decoration:none;border-radius:var(--r-sm)}
.menu-drawer a svg{width:18px;height:18px}
.menu-drawer a:hover,.menu-drawer a[aria-current="page"]{background:var(--panel-2)}
.drawer-languages{margin-top:16px;padding-top:16px;border-top:1px solid var(--border)}
.drawer-languages a[aria-current="true"]{color:var(--accent-dark);background:var(--pink-soft)}
.menu-veil{display:none;position:fixed;inset:var(--header-height) 0 0;border:0;background:var(--veil);z-index:60}
.site-footer{position:relative;background:linear-gradient(180deg,var(--panel-2),var(--bg));padding-top:56px;padding-bottom:24px;overflow-x:clip}
.footer-grid{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:40px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:340px;color:var(--muted)}
.footer-title{margin:0 0 14px;font-size:16px;font-weight:700}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 16px;list-style:none;margin:0;padding:0}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;text-decoration:none;font-size:14px}
.footer-links a:hover{color:var(--accent-dark)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;padding-block:24px}
.footer-languages a{display:inline-flex;align-items:center;min-height:32px;font-size:14px}
.footer-languages a[aria-current="true"]{font-weight:700}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;border-top:1px solid var(--border);padding-top:20px;color:var(--muted);font-size:13px}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px}
@media(max-width:1360px){
  .nav a svg{display:none}
  .nav a{padding:0 8px;font-size:13px}
}
@media(max-width:900px){
  .topbar-in{padding-inline:24px;gap:12px}
  .nav a{padding-inline:9px}
  .grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
}
@media(max-width:768px){
  :root{--gutter:16px}
  h1{font-size:40px;line-height:1.1}
  h2{font-size:30px}
  h3{font-size:22px}
  .topbar-in{padding-inline:16px;gap:8px}
  .nav,.brand-zh{display:none}
  .tools{margin-left:auto;gap:4px}
  .tools::before{display:none}
  .lang{padding-inline:10px;min-height:44px}
  .lang span{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
  .login{min-height:40px;padding-inline:16px}
  .menu-toggle{display:inline-flex}
  .menu-drawer:not([hidden]){display:block}
  .menu-veil:not([hidden]){display:block}
  .section{padding-top:44px;padding-bottom:44px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.tilt-decor{transform:none}
  .section,.hero{max-width:100%}
  .grid,.footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-brand{grid-column:auto}
  .footer-grid{gap:28px}
  .panel,.card{padding:22px}
  .brand-en{font-size:17px}
  .brand{gap:7px}
  .brand img{width:28px;height:28px}
}
@media(max-width:480px){
  .btn{min-height:48px;padding:10px 22px;font-size:16px}
  .btn-small{min-height:40px;font-size:14px}
  .cta-row{gap:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}