:root{
  --bg:#FAFBFD;--bg-panel:#FFFFFF;--bg-panel-2:#EEF2FB;--bg-panel-3:#E3E9F8;--border:#E2E6F0;
  --accent:#1652F0;--accent-2:#5B8CFF;--accent-dark:#0B3BC2;
  --text:#0E1220;--text-muted:#5A6275;--text-soft:#8A93A6;--wall-ink:#A4ABBA;
  --success:#16A34A;--warn:#D97706;--error:#DC2626;
  --sky:#DCE6FF;--mist:#F2F5FD;--sea-1:#CCDAFB;--sea-2:#A9C0F5;
  --sun:rgba(255,255,255,.95);--sun-0:rgba(255,255,255,0);
  --atmo-1:rgba(22,82,240,.055);--atmo-2:rgba(22,82,240,.018);--atmo-0:rgba(22,82,240,0);
  --spot:rgba(120,170,255,.30);
  --accent-a06:rgba(22,82,240,.06);--accent-a12:rgba(22,82,240,.12);--accent-a20:rgba(22,82,240,.20);
  --accent-a35:rgba(22,82,240,.35);--accent2-a55:rgba(91,140,255,.55);--accent-deep-a35:rgba(11,59,194,.35);
  --hl:rgba(255,255,255,.95);--hl-soft:rgba(255,255,255,.26);
  --glass:rgba(255,255,255,.56);--glass-strong:rgba(255,255,255,.72);--glass-line:rgba(255,255,255,.80);
  --ink-glass:rgba(14,18,32,.58);--ink-glass-2:rgba(255,255,255,.12);--ink-shadow:rgba(14,18,32,.18);
  --on-ink:#FFFFFF;--on-ink-soft:rgba(255,255,255,.80);--header-bg:rgba(250,251,253,.84);--dot:#C5CCDC;
  --flag-red:#D3263A;--flag-navy:#1C2A6E;--flag-blue:#1F4FB0;--flag-white:#FFFFFF;--flag-edge:rgba(14,18,32,.14);
  --clear:transparent;
  --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,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --weight-body:400;--weight-medium:500;--weight-semibold:600;--weight-bold:700;--weight-heavy:800;--weight-display:900;
  --text-xs:12px;--text-sm:13px;--text-nav:15px;--text-base:16px;--text-lede:18px;--text-h3:24px;--text-h2:36px;--text-h1:66px;
  --leading-body:1.6;--leading-title:1.15;--tracking-title:-.03em;
  --r-window:32px;--r-screen:24px;--r-card:16px;--r-chip:12px;--r-pill:999px;--r-focus:6px;
  --r-mobile-window:20px;--r-mobile-screen:15px;--r-cap:14px;--r-cap-inner:9px;--r-icon:11px;--r-dot:50%;
  --shadow-panel:0 32px 80px var(--accent-a12),0 4px 14px var(--accent-a06);
  --shadow-float:0 18px 44px var(--accent-a12),0 2px 6px var(--accent-a06);
  --shadow-cta:0 10px 26px var(--accent-a20);
  --gutter:24px;--width-page:1200px;--width-head:1360px;--width-reading:800px;
  --head-height:68px;--toc-height:60px;--anchor-gap:16px;
  --space-section:80px;--ease: .2s ease;--reveal-time:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--head-height) + var(--anchor-gap));scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-base);line-height:var(--leading-body);font-weight:var(--weight-body);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
a{color:inherit;text-underline-offset:4px}
button,input,select,textarea{font:inherit}
button{color:inherit;cursor:pointer}
button,select,input,textarea{max-width:100%}
button{border:0}
img{max-width:100%;height:auto}
svg{flex-shrink:0;vertical-align:middle}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-focus)}
[hidden]{display:none!important}
h1,h2,h3{font-family:var(--font-display);color:var(--text);text-wrap:balance}
h1{margin:0 0 16px;font-size:clamp(52px,5vw,var(--text-h1));line-height:var(--leading-title);font-weight:var(--weight-display);letter-spacing:var(--tracking-title)}
h2{margin:0 0 16px;font-size:var(--text-h2);line-height:var(--leading-title);font-weight:var(--weight-display);letter-spacing:var(--tracking-title)}
h3{margin:0 0 12px;font-size:var(--text-h3);line-height:1.3;font-weight:var(--weight-heavy)}
p{margin:0 0 20px}
strong{font-weight:var(--weight-bold)}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:var(--width-page);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--width-reading);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:var(--space-section);padding-bottom:var(--space-section)}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-five{grid-template-columns:repeat(5,minmax(0,1fr))}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.panel,.card{min-width:0;padding:32px;border:1px solid var(--border);border-radius:var(--r-window);background:var(--bg-panel);box-shadow:inset 0 1px 0 var(--hl),var(--shadow-panel)}
.card{border-radius:var(--r-card);padding:24px;box-shadow:inset 0 1px 0 var(--hl),var(--shadow-float)}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--bg-panel-2);border-radius:var(--r-card)}
pre code{overflow-wrap:normal;white-space:pre}
.prose{min-width:0;overflow-wrap:break-word}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose li{margin-bottom:8px}
.prose a{color:var(--accent-dark)}
.decor-section{position:relative;overflow-x:clip;max-width:100%}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:32px}
.skip{position:absolute;left:16px;top:-60px;z-index:100;padding:10px 16px;border-radius:var(--r-pill);background:var(--accent);color:var(--on-ink);font-weight:var(--weight-bold);text-decoration:none}
.skip:focus{top:12px}
.pill,.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:42px;padding:0 20px;border:1px solid var(--clear);border-radius:var(--r-pill);font-size:var(--text-nav);font-weight:var(--weight-bold);line-height:1.2;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:background-color var(--ease),transform var(--ease)}
.pill-solid,.btn-primary{background:var(--accent);color:var(--on-ink);box-shadow:inset 0 1px 0 var(--hl-soft),var(--shadow-cta)}
.pill-solid:hover,.btn-primary:hover{background:var(--accent-dark)}
.prose a.btn-primary{color:var(--on-ink)}
.pill-soft,.btn-secondary{background:var(--bg-panel-2);color:var(--text)}
.pill-soft:hover,.btn-secondary:hover{background:var(--bg-panel-3)}
.btn-outline{background:var(--bg-panel);border-color:var(--border);color:var(--accent-dark)}
.btn:active,.pill:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none;cursor:not-allowed}
.btn[aria-disabled="true"]{pointer-events:none}
.site-head,#site-header{position:sticky;top:0;z-index:50}
.head-in{max-width:var(--width-head);margin:0 auto;padding:0 32px;height:var(--head-height);display:flex;align-items:center;gap:24px}
.head-surface{background:var(--header-bg);backdrop-filter:saturate(160%) blur(14px);-webkit-backdrop-filter:saturate(160%) blur(14px);border-bottom:1px solid var(--border)}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex:none}
.brand img{width:30px;height:30px;flex:none}
.brand-en{font-family:var(--font-display);font-weight:var(--weight-heavy);font-size:19px;line-height:1;letter-spacing:-.02em}
.brand-zh{font-size:var(--text-sm);font-weight:var(--weight-medium);line-height:1;color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border)}
.tabs{flex:1;display:flex;justify-content:center;min-width:0}
.tabs ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px;flex-wrap:nowrap}
.tab{position:relative;display:flex;align-items:center;height:var(--head-height);padding:0 12px;font-size:var(--text-nav);font-weight:var(--weight-medium);color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--ease)}
.tab::after{content:"";position:absolute;left:12px;right:12px;bottom:-1px;height:3px;border-radius:var(--r-focus) var(--r-focus) 0 0;background:var(--accent);transform:scaleX(0);transition:transform .25s ease}
.tab:hover{color:var(--text)}
.tab:hover::after{transform:scaleX(.35)}
.tab[aria-current="page"]{color:var(--text);font-weight:var(--weight-bold)}
.tab[aria-current="page"]::after{transform:scaleX(1)}
.head-actions{display:flex;align-items:center;gap:10px;flex-shrink:0}
.lang-box{position:relative;flex:none}
.lang{appearance:none;border:0;background:none;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:36px;min-width:44px;width:auto;padding:8px 10px;border-radius:var(--r-pill);font-size:14px;font-weight:var(--weight-medium);color:var(--text-muted)}
.lang span{white-space:nowrap}
.lang:hover{background:var(--bg-panel-2);color:var(--text)}
.lang-panel{position:absolute;right:0;top:calc(100% + 12px);z-index:65;min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-float)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-chip)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--bg-panel-2);color:var(--accent-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;background:var(--bg-panel-2);border-radius:var(--r-pill)}
.menu-line{display:block;width:20px;height:2px;background:currentColor;border-radius:var(--r-focus)}
.mobile-drawer{position:fixed;top:var(--head-height);right:0;left:0;z-index:49;height:calc(100dvh - var(--head-height));max-height:calc(100dvh - var(--head-height));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:16px var(--gutter) 32px;border-top:1px solid var(--border)}
.drawer-links{display:grid;grid-template-columns:minmax(0,1fr);list-style:none;margin:0;padding:0;width:100%}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;text-decoration:none;border-bottom:1px solid var(--border);color:var(--text)}
.mobile-drawer a[aria-current="page"],.mobile-drawer a:hover{background:var(--bg-panel-2);color:var(--accent-dark)}
.drawer-languages{margin-top:20px}
.nav-veil{position:fixed;inset:var(--head-height) 0 0;z-index:48;background:var(--ink-glass)}
html.nav-open{overflow:hidden}
.site-foot{border-top:1px solid var(--border);background:linear-gradient(180deg,var(--bg-panel-2),var(--bg));padding-top:56px;padding-bottom:24px}
.foot-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:40px}
.foot-grid>*{min-width:0}
.foot-brand p{margin-top:20px;color:var(--text-muted);max-width:340px}
.foot-heading{font-size:var(--text-base);font-weight:var(--weight-heavy);margin:0 0 16px}
.foot-links{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:8px 20px}
.foot-links li{min-width:0}
.foot-links a{display:inline-flex;align-items:center;min-height:28px;text-decoration:none;font-size:14px;color:var(--text-muted)}
.foot-links a:hover{color:var(--accent-dark);text-decoration:underline}
.foot-languages{display:flex;flex-wrap:wrap;gap:12px 24px;margin-top:32px;padding-top:24px;border-top:1px solid var(--border)}
.foot-languages a{display:inline-flex;align-items:center;min-height:28px;font-size:14px;text-decoration:none}
.foot-bottom{margin-top:24px;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;color:var(--text-muted);font-size:var(--text-sm)}
.foot-bottom p{margin:0}
.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}
@media(max-width:1240px){
  .head-in{padding:0 20px;gap:16px}
  .tab{padding:0 9px;font-size:14px}
  .tab::after{left:9px;right:9px}
  .lang-txt{display:none}
}
@media(max-width:1100px){
  .tabs{display:none}
  .head-actions{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .head-start{display:none}
}
@media(min-width:1101px){
  .mobile-drawer,.nav-veil{display:none!important}
}
@media(max-width:900px){
  .grid-five{grid-template-columns:repeat(3,minmax(0,1fr))}
  .foot-grid{grid-template-columns:1fr 1fr}
  .foot-brand{grid-column:1/-1}
}
@media(max-width:768px){
  :root{--head-height:56px;--gutter:16px;--space-section:56px;--text-h2:28px;--text-h3:21px}
  h1{font-size:36px;line-height:1.15}
  .head-in{padding:0 16px;gap:10px;flex-wrap:nowrap}
  .head-actions{margin-left:auto;gap:6px}
  .head-actions .pill{min-height:36px;padding:0 14px;font-size:14px}
  .lang{padding:8px}
  .grid-three{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .panel{padding:24px;border-radius:var(--r-mobile-window)}
  .foot-grid{gap:24px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .decor-section{max-width:100%;overflow-x:clip}
}
@media(max-width:420px){
  .brand-en{font-size:17px}
  .head-actions{gap:4px}
  .head-actions .pill{padding:0 12px}
  .foot-grid{grid-template-columns:1fr}
  .foot-brand{grid-column:auto}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}