:root {
  --bg:#E5EDF2;
  --bg-top:#EEF4F7;
  --bg-bottom:#DDE7EE;
  --panel:#F7FAFC;
  --panel-2:#D8E3EA;
  --surface:#FFFFFF;
  --well:#EAF0F4;
  --well-deep:#DFE7EE;
  --border:#C5D3DD;
  --border-soft:#D9E3EA;
  --chip-face:#EEF3F7;
  --chip-edge:#C9D6E0;
  --accent:#1D57D6;
  --accent-dark:#1440A8;
  --cyan:#2BA7C9;
  --cyan-sheen:rgba(43,167,201,.34);
  --accent-soft:rgba(29,87,214,.10);
  --accent-wash:rgba(29,87,214,.06);
  --accent-line:rgba(29,87,214,.28);
  --dot:rgba(29,87,214,.04);
  --transparent:transparent;
  --mask-on:#000000;
  --text:#0F1B2A;
  --text-muted:#4F6072;
  --text-faint:#7B8B9B;
  --success:#1F8A5B;
  --success-soft:rgba(31,138,91,.12);
  --warn:#B7791F;
  --warn-soft:rgba(183,121,31,.10);
  --error:#C8372D;
  --error-soft:rgba(200,55,45,.10);
  --ink:#10202A;
  --on-ink:#FFFFFF;
  --on-ink-muted:rgba(255,255,255,.76);
  --hi:rgba(255,255,255,.94);
  --chrome-dot:#C3D0DA;
  --shade-inset:rgba(15,27,42,.06);
  --veil:rgba(16,32,42,.36);
  --flag-red:#D52B1E;
  --flag-white:#FFFFFF;
  --flag-blue:#22408C;
  --flag-edge:rgba(15,27,42,.16);
  --sh-board:0 44px 88px -30px rgba(29,87,214,.22),0 18px 40px -22px rgba(29,87,214,.12);
  --sh-win:0 1px 0 var(--hi) inset,0 18px 36px -20px rgba(29,87,214,.26),0 2px 6px rgba(15,27,42,.05);
  --sh-float:0 24px 46px -16px rgba(29,87,214,.30),0 4px 10px rgba(15,27,42,.06);
  --sh-chip:0 1px 0 var(--hi) inset,0 6px 14px -7px rgba(29,87,214,.24),0 1px 2px rgba(15,27,42,.06);
  --sh-device:0 1px 0 var(--hi) inset,0 3px 0 var(--chip-edge),0 16px 28px -12px rgba(29,87,214,.40);
  --sh-btn:0 14px 26px -12px rgba(29,87,214,.60),0 1px 0 rgba(255,255,255,.26) inset;
  --r-tail:3px;
  --r-xs:6px;
  --r-sm:8px;
  --r-md:10px;
  --r-lg:12px;
  --r-pill:999px;
  --r-round:50%;
  --f-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei","Malgun Gothic",system-ui,sans-serif;
  --f-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei","Malgun Gothic",system-ui,sans-serif;
  --f-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --gutter:clamp(20px,5.5vw,80px);
  --content-width:1280px;
  --header-height:64px;
  --announcement-height:36px;
  --menu-top:100px;
  --toc-offset:16px;
  --anchor-offset:136px;
  --ease: .2s ease;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:80px}
html,body{margin:0}
body{font-family:var(--f-body);color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;line-height:1.6}
[hidden]{display:none!important}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
button,input,select,textarea{font:inherit}
button{cursor:pointer;color:inherit}
button,a,input,summary,select,textarea{-webkit-tap-highlight-color:var(--accent-soft)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
a{color:inherit;text-underline-offset:4px}
button{border:0}
h1,h2,h3,h4{font-family:var(--f-display);color:var(--text);margin:0 0 20px;text-wrap:balance}
h1{font-size:clamp(52px,4.45vw,64px);font-weight:800;line-height:1.1;letter-spacing:-.02em}
h2{font-size:clamp(30px,3.1vw,44px);font-weight:750;line-height:1.2;letter-spacing:-.02em}
h3{font-size:22px;line-height:1.35;font-weight:700}
p{margin:0 0 20px}
small{font-size:.85em}
strong{font-weight:650}
.no-break{white-space:nowrap}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums}
.text-muted{color:var(--text-muted)}
.text-accent{color:var(--accent)}
.wrap{width:100%;max-width:calc(var(--content-width) + 2 * var(--gutter));padding-inline:var(--gutter);margin-inline:auto}
.section{padding-top:80px;padding-bottom:80px}
.section-head{max-width:760px;margin-bottom:32px}
.section-head p{color:var(--text-muted);font-size:18px}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-5{grid-template-columns:repeat(5,minmax(0,1fr))}
.stack{display:flex;flex-direction:column;gap:20px;min-width:0}
.row{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.panel,.card{min-width:0;border:1px solid var(--border-soft);border-radius:var(--r-sm);background:var(--surface);box-shadow:var(--sh-chip)}
.panel{padding:28px;background:var(--panel)}
.card{padding:24px}
.prose{max-width:80ch;min-width:0;overflow-wrap:break-word}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose p,.prose li{line-height:1.85}
.prose a{color:var(--accent-dark)}
code{font-family:var(--f-mono);font-size:.88em;overflow-wrap:anywhere;word-break:break-word;background:var(--well);border-radius:var(--r-tail);padding:2px 5px}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:20px;background:var(--ink);color:var(--on-ink);border-radius:var(--r-sm)}
pre code{padding:0;background:var(--transparent);color:inherit;white-space:pre;overflow-wrap:normal;word-break:normal}
blockquote{margin:24px 0}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
.btn{position:relative;display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 24px;border:1px solid var(--transparent);border-radius:var(--r-pill);font-family:var(--f-body);font-size:15.5px;font-weight:600;line-height:1.4;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--ease),box-shadow var(--ease),background var(--ease),border-color var(--ease)}
.btn svg{width:16px;height:16px}
.btn span{position:relative}
.btn-primary{overflow:hidden;color:var(--on-ink);background:linear-gradient(135deg,var(--accent),var(--accent-dark));box-shadow:var(--sh-btn)}
.btn-primary::before{content:"";position:absolute;inset:0;background:linear-gradient(120deg,var(--transparent) 46%,var(--cyan-sheen))}
.btn-primary:hover{transform:translateY(-1px);box-shadow:var(--sh-float)}
.btn-ghost,.btn-secondary{color:var(--text);background:var(--panel);border-color:var(--border);box-shadow:inset 0 1px 0 var(--hi)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--surface);border-color:var(--accent-line)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.55;cursor:not-allowed;box-shadow:none;transform:none}
.btn-small{min-height:36px;padding:7px 16px;font-size:13px}
.badge{display:inline-flex;align-items:center;gap:8px;min-height:30px;padding:4px 12px;border-radius:var(--r-sm);background:var(--accent-soft);color:var(--accent);font-size:13.5px;font-weight:600;line-height:1.4}
.badge-dot{flex-shrink:0;width:7px;height:7px;border-radius:var(--r-round);background:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.tag{display:inline-block;max-width:100%;overflow:hidden;overflow-wrap:anywhere;vertical-align:middle;padding:4px 10px;border-radius:var(--r-pill);background:var(--well);color:var(--text-muted);font-size:12px}
.status{display:inline-flex;align-items:center;gap:6px;padding:3px 9px;border-radius:var(--r-pill);background:var(--success-soft);color:var(--success);font-size:11px;font-weight:600;line-height:1.5}
.status-info{color:var(--accent);background:var(--accent-soft)}
.status-warn{color:var(--warn);background:var(--warn-soft)}
.status-error{color:var(--error);background:var(--error-soft)}
.defs{position:absolute;width:0;height:0;overflow:hidden}
.fl-red{fill:var(--flag-red)}
.fl-white{fill:var(--flag-white)}
.fl-blue{fill:var(--flag-blue)}
.s-accent{stop-color:var(--accent)}
.s-accent-dark{stop-color:var(--accent-dark)}
.s-cyan{stop-color:var(--cyan)}
.flag{position:relative;display:inline-flex;flex:none;width:21px;height:14px;border-radius:var(--r-tail);overflow:hidden}
.flag svg{display:block;width:21px;height:14px}
.flag::after{content:"";position:absolute;inset:0;border-radius:inherit;box-shadow:inset 0 0 0 1px var(--flag-edge)}
.announce{position:relative;background:var(--ink);color:var(--on-ink)}
.announce-in{display:flex;align-items:center;justify-content:center;gap:14px;min-height:var(--announcement-height);font-size:13.5px;font-weight:500;letter-spacing:.01em;padding-right:40px}
.ann-btn{display:inline-flex;align-items:center;justify-content:center;min-height:24px;padding:2px 12px;border-radius:var(--r-pill);background:var(--accent);color:var(--on-ink);font-size:12.5px;font-weight:600;text-decoration:none;flex-shrink:0}
.ann-btn:hover{background:var(--accent-dark)}
.ann-x{position:absolute;right:var(--gutter);top:50%;transform:translateY(-50%);display:grid;place-items:center;width:26px;height:26px;border-radius:var(--r-xs);background:var(--transparent);color:var(--on-ink-muted);cursor:pointer}
.ann-x:hover{color:var(--on-ink)}
.ann-x svg{width:14px;height:14px}
.ann-toggle{position:absolute;opacity:0;width:1px;height:1px}
.ann-toggle:checked+.announce{display:none}
.ann-toggle:focus-visible+.announce .ann-x{outline:2px solid var(--accent);outline-offset:2px}
html.announce-dismissed{--menu-top:64px}
.topbar{position:relative;z-index:52}
.topbar-in{display:flex;align-items:center;gap:32px;min-height:var(--header-height);flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;flex:none;min-height:32px}
.brand-mark{width:28px;height:28px;display:block}
.brand-en{font-family:var(--f-display);font-size:20px;font-weight:800;letter-spacing:-.02em;white-space:nowrap}
.brand-zh{padding-left:10px;border-left:1px solid var(--border);font-size:14px;font-weight:500;color:var(--text-muted)}
.nav{flex:1;display:flex;justify-content:center;min-width:0}
.nav-list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:0}
.nav-list li{display:flex;align-items:center}
.nav-list li+li::before{content:"·";margin:0 12px;color:var(--text-faint);font-weight:700}
.nav-list a{display:inline-flex;align-items:center;min-height:32px;padding:6px 1px;font-size:14.5px;font-weight:500;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--ease)}
.nav-list a:hover{color:var(--text)}
.nav-list a[aria-current="page"]{color:var(--text);font-weight:600;box-shadow:inset 0 -2px 0 var(--accent)}
.nav-tools{position:relative;display:flex;align-items:center;gap:10px;flex-shrink:0;z-index:55}
.language{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;min-height:38px;padding:7px 10px;border:0;border-radius:var(--r-sm);background:var(--transparent);font-size:14px;color:var(--text-muted)}
.lang span{white-space:nowrap}
.lang:hover{background:var(--accent-wash);color:var(--text)}
.lang svg{width:12px;height:12px}
.lang-panel{position:absolute;right:0;top:calc(100% + 8px);z-index:80;min-width:168px;padding:6px;background:var(--surface);border:1px solid var(--border);border-radius:var(--r-sm);box-shadow:var(--sh-float)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-xs);font-size:14px}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--accent-soft);color:var(--accent-dark)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:8px 20px;border-radius:var(--r-pill);background:var(--ink);color:var(--on-ink);font-size:14px;font-weight:600;line-height:1.4;text-decoration:none;box-shadow:inset 0 1px 0 var(--hi);white-space:nowrap}
.login:hover{background:var(--accent-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border-radius:var(--r-sm);background:var(--transparent);color:var(--text)}
.menu-toggle svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:2}
.menu-toggle[aria-expanded="true"]{background:var(--accent-soft);color:var(--accent)}
.mobile-drawer{position:fixed;top:var(--menu-top);right:0;left:0;z-index:53;height:calc(100dvh - var(--menu-top));max-height:calc(100dvh - var(--menu-top));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);border-top:1px solid var(--border);padding:16px var(--gutter) 32px}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 14px;text-decoration:none;border-bottom:1px solid var(--border-soft)}
.mobile-drawer a[aria-current]{color:var(--accent-dark);background:var(--accent-soft)}
.drawer-languages{margin-top:20px;border-top:1px solid var(--border)}
.nav-veil{position:fixed;inset:var(--menu-top) 0 0;z-index:51;background:var(--veil)}
html.nav-open{overflow:hidden}
.site-footer{background:var(--well-deep);border-top:1px solid var(--border);padding-top:56px;padding-bottom:24px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:40px}
.footer-grid>*{min-width:0}
.footer-brand p{max-width:32ch;margin-top:18px;color:var(--text-muted);font-size:14px}
.footer-title{font-size:14px;font-weight:700;margin-bottom:14px}
.footer-links{display:flex;flex-direction:column;align-items:flex-start;gap:4px;margin:0;padding:0;list-style:none}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;color:var(--text-muted);font-size:13px;text-decoration:none}
.footer-links a:hover{color:var(--accent)}
.footer-bottom{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;border-top:1px solid var(--border);margin-top:40px;padding-top:20px;color:var(--text-muted);font-size:12px}
.footer-legal{display:flex;gap:18px;flex-wrap:wrap}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px}
.reveal{transition:opacity .35s ease,transform .35s ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-width:0;max-width:100%;min-height:160px;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}
.decorated{position:relative;overflow-x:clip}
@media(min-width:1101px){
  .mobile-drawer,.nav-veil{display:none!important}
}
@media(max-width:1200px){
  .topbar-in{gap:20px}
  .nav-list li+li::before{margin:0 8px}
  .nav-list a{font-size:13px}
  .footer-grid{gap:24px}
}
@media(max-width:1100px){
  .nav{display:none}
  .nav-tools{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .topbar-in{gap:16px}
}
@media(max-width:768px){
  h1{font-size:clamp(28px,5.2vw,40px)}
  h2{font-size:32px}
  .section{padding-top:48px;padding-bottom:48px}
  .grid-3{grid-template-columns:1fr}
  .grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:20px}
  .no-break{white-space:normal}
  .grid-2{grid-template-columns:1fr}
  .tilt,[data-tilt]{transform:none}
  .decorated{max-width:100%;overflow-x:clip}
  .topbar-in{gap:8px}
  .nav-tools{gap:4px;margin-left:auto}
  .brand{gap:6px}
  .brand-mark{width:24px;height:24px}
  .brand-en{font-size:17px}
  .lang{font-size:12px;padding:6px;gap:3px}
  .login{padding:7px 12px;font-size:13px}
  .announce-in{font-size:11px;gap:8px;justify-content:flex-start}
  .ann-btn{padding-inline:8px;font-size:11px}
  .ann-x{right:10px}
  .panel,.card{padding:20px}
  .footer-grid{gap:24px 20px}
  .footer-bottom{flex-direction:column}
}
@media(max-width:359px){
  :root{--gutter:16px}
  .brand-en{font-size:15px}
  .brand-mark{width:22px;height:22px}
  .lang{font-size:11px}
  .login{padding-inline:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}