:root{
  --bg:#FBFCFB;--panel:#FFFFFF;--panel-2:#F1F5F3;--border:#E1E8E4;--line-strong:#C6D2CB;
  --accent:#10C27E;--accent-dark:#077A50;--accent-2:#6FD7AE;--forest:#0E2A21;--forest-2:#173D30;
  --text:#121815;--muted:#5D6A64;--muted-2:#89968F;--success:#1A9E5C;--warn:#D88A0E;--error:#D3473E;
  --on-dark:#EEF7F2;--on-dark-muted:rgba(238,247,242,.68);
  --accent-a06:rgba(16,194,126,.06);--accent-a10:rgba(16,194,126,.10);--accent-a12:rgba(16,194,126,.12);--accent-a16:rgba(16,194,126,.16);--accent-a22:rgba(16,194,126,.22);
  --ink-a08:rgba(14,42,33,.08);--ink-a14:rgba(14,42,33,.14);
  --white-a08:rgba(255,255,255,.08);--white-a35:rgba(255,255,255,.35);--white-a50:rgba(255,255,255,.5);--white-a95:rgba(255,255,255,.95);
  --topbar-bg:rgba(251,252,251,.84);--hero-top:#FFFFFF;--hero-bottom:#F1F5F3;--veil-bg:rgba(14,42,33,.3);
  --flag-red:#D7322B;--flag-blue:#23418D;--flag-white:#FFFFFF;--flag-line:rgba(18,24,21,.16);--clear:transparent;
  --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;
  --r-xs:4px;--r-sm:6px;--r-md:8px;--r-lg:10px;--r-band:12px;--r-pill:999px;--r-round:50%;
  --shadow-panel:0 36px 88px -12px rgba(16,194,126,.12),0 22px 44px -26px rgba(14,42,33,.16);
  --shadow-float:0 22px 46px -16px rgba(16,194,126,.26),0 8px 18px -10px rgba(14,42,33,.16);
  --shadow-card:0 30px 60px -28px rgba(7,122,80,.42),0 10px 24px -14px rgba(14,42,33,.18);
  --shadow-btn:0 12px 26px -12px rgba(16,194,126,.75);
  --edge:inset 0 1px 0 rgba(255,255,255,.95),inset 0 0 0 1px rgba(255,255,255,.5);
  --wrap:1248px;--gutter:48px;--header-height:68px;--toc-offset:calc(var(--header-height) + 12px);--chapter-offset:calc(var(--header-height) + 88px);
  --size-body:16px;--size-small:14px;--size-h1:clamp(52px,4.6vw,68px);--size-h2:clamp(28px,3vw,40px);--size-h3:22px;
  --weight-body:400;--weight-medium:600;--weight-bold:700;--weight-heading:800;--weight-display:900;
  --ease-time:.2s;--reveal-time:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--header-height) + 16px);scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--size-body);line-height:1.6;-webkit-font-smoothing:antialiased;overflow-x:clip}
[hidden]{display:none!important}
a{color:inherit;text-underline-offset:.2em}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,summary,a,input,select,textarea{touch-action:manipulation}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);font-weight:var(--weight-heading);line-height:1.2;text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--size-h1);font-weight:var(--weight-display);letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:var(--size-h2);letter-spacing:-.02em;margin:0 0 20px}
h3{font-size:var(--size-h3);margin:0 0 12px}
p{margin:0 0 18px}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;font-size:.9em;background:var(--panel-2);border-radius:var(--r-xs);padding:.1em .3em}
pre{max-width:100%;overflow-x:auto;background:var(--forest);color:var(--on-dark);border-radius:var(--r-md);padding:20px;line-height:1.7}
pre code{padding:0;background:var(--clear);color:inherit;overflow-wrap:normal;white-space:pre}
blockquote{margin:24px 0}
.wrap{width:100%;max-width:calc(var(--wrap) + 2 * var(--gutter));padding-inline:var(--gutter);margin-inline:auto}
.section{padding-top:80px;padding-bottom:80px}
.section--tight{padding-top:40px;padding-bottom:40px}
.grid{display:grid;gap:24px}
.grid--three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--five{grid-template-columns:repeat(5,minmax(0,1fr))}
:where(.grid,.hero__grid,.band__grid,.features-layout,.footer-grid)>*{min-width:0}
.stack>*+*{margin-top:24px}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.ico{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.skip{position:absolute;left:16px;top:8px;z-index:100;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;padding:0;border-radius:var(--r-md);background:var(--forest);color:var(--on-dark);text-decoration:none}
.skip:focus{width:auto;height:auto;overflow:visible;clip-path:none;padding:8px 14px}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;text-decoration:none;color:var(--text);font-family:var(--font-display);font-weight:var(--weight-heading);font-size:19px;letter-spacing:-.02em;white-space:nowrap}
.logo{display:block;flex:none}
.brand .logo{width:32px;height:32px}
.brand__zh{color:var(--muted);font-weight:var(--weight-medium)}
#site-header{position:sticky;top:0;z-index:80}
.topbar{position:sticky;top:0;z-index:80;background:var(--topbar-bg);backdrop-filter:saturate(1.4) blur(12px);-webkit-backdrop-filter:saturate(1.4) blur(12px);box-shadow:0 1px 0 var(--border)}
.topbar__in{display:flex;align-items:center;gap:32px;height:var(--header-height);flex-wrap:nowrap}
.mainnav{flex:1;min-width:0}
.mainnav ul{display:flex;align-items:center;justify-content:center;gap:2px;list-style:none;margin:0;padding:0}
.mainnav a{display:inline-flex;align-items:center;gap:6px;padding:8px 12px;min-height:38px;border-radius:var(--r-md);color:var(--text);text-decoration:none;font-size:14.5px;font-weight:500;white-space:nowrap;transition:background-color var(--ease-time),color var(--ease-time)}
.mainnav a svg{width:16px;height:16px;color:var(--muted)}
.mainnav a:hover{background:var(--panel-2)}
.mainnav a[aria-current="page"]{color:var(--accent-dark);background:var(--accent-a10);font-weight:var(--weight-medium)}
.mainnav a[aria-current="page"] svg{color:var(--accent-dark)}
.topbar__end{display:flex;align-items:center;gap:8px;flex-shrink:0}
.lang-control{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:38px;min-width:44px;width:auto;padding:0 12px;border:0;border-radius:var(--r-md);background:var(--clear);font-size:var(--size-small);color:var(--text);white-space:nowrap}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px;color:var(--muted)}
.lang:hover{background:var(--panel-2)}
.lang-panel{position:absolute;right:0;top:calc(100% + 10px);z-index:100;min-width:180px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-lg);box-shadow:var(--shadow-panel)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-sm)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--accent-a10);color:var(--accent-dark)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:0 22px;border-radius:var(--r-pill);background:var(--accent);color:var(--forest);font-size:14.5px;font-weight:var(--weight-bold);text-decoration:none;white-space:nowrap;box-shadow:var(--shadow-btn),inset 0 1px 0 var(--white-a35);transition:transform var(--ease-time)}
.login:hover{transform:translateY(-1px)}
.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-md);background:var(--panel);color:var(--text)}
.menu-toggle svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.nav-drawer{position:fixed;top:var(--header-height);right:0;left:0;z-index:75;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);padding:16px var(--gutter) 32px;border-top:1px solid var(--border)}
.nav-drawer a{display:flex;align-items:center;gap:12px;width:100%;min-height:48px;padding:12px 16px;text-decoration:none;border-radius:var(--r-md)}
.nav-drawer a:hover,.nav-drawer a[aria-current]{background:var(--accent-a10);color:var(--accent-dark)}
.drawer-languages{margin-top:16px;padding-top:16px;border-top:1px solid var(--border)}
.nav-veil{position:fixed;inset:var(--header-height) 0 0;z-index:70;border:0;background:var(--veil-bg)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:12px 26px;border:0;border-radius:var(--r-md);font-size:var(--size-body);font-weight:var(--weight-bold);text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--ease-time),box-shadow var(--ease-time)}
.btn svg{width:18px;height:18px}
.btn:hover{transform:translateY(-1px)}
.btn:active{transform:translateY(1px)}
.btn--primary,.btn-primary{background:linear-gradient(180deg,var(--accent-2) -50%,var(--accent) 62%);color:var(--forest);box-shadow:var(--shadow-btn),inset 0 1px 0 var(--white-a50)}
.btn--ghost{background:var(--panel);color:var(--text);box-shadow:inset 0 0 0 1.5px var(--line-strong)}
.btn--ghost:hover{box-shadow:inset 0 0 0 1.5px var(--accent-dark)}
.btn--small{min-height:44px;padding:9px 16px;font-size:var(--size-small)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--panel-2);color:var(--muted);box-shadow:none;cursor:not-allowed;transform:none}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--r-lg);padding:24px;box-shadow:var(--shadow-panel),var(--edge)}
.prose{max-width:80ch;overflow-wrap:break-word}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose li+li{margin-top:8px}
.prose a{color:var(--accent-dark)}
.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}
#server-status{position:relative;display:block;min-width:0;min-height:120px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:24px}
#server-status :where(.grid,[class*="grid"]){min-width:0;max-width:100%}
.site-footer{background:var(--panel-2);border-top:1px solid var(--border);padding-top:56px;padding-bottom:28px}
.footer-grid{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:48px}
.footer-brand p{margin:16px 0 0;max-width:32em;color:var(--muted);font-size:var(--size-small)}
.footer-title{font-size:var(--size-body);font-weight:var(--weight-bold);margin:0 0 14px}
.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,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;padding-block:4px;text-decoration:none;font-size:var(--size-small)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent-dark);text-decoration:underline}
.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;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;margin-top:20px;font-size:13px;color:var(--muted)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
@media(min-width:1181px) and (max-width:1380px){
  .topbar__in{gap:18px}
  .mainnav a{padding-inline:8px;font-size:13px}
  .lang{padding-inline:8px}
}
@media(max-width:1180px){
  .topbar__in{gap:16px}
  .mainnav{display:none}
  .topbar__end{margin-left:auto}
  .menu-toggle{display:inline-flex}
}
@media(max-width:768px){
  :root{--gutter:24px;--size-h1:clamp(28px,6vw,40px);--size-h2:30px}
  .section{padding-top:56px;padding-bottom:56px}
  .grid--three{grid-template-columns:1fr}
  .grid--five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr;gap:28px}
}
@media(max-width:640px){
  :root{--gutter:16px;--header-height:64px}
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .brand{gap:6px;font-size:16px}
  .brand .logo{width:27px;height:27px}
  .topbar__in{gap:6px}
  .topbar__end{gap:4px;margin-left:auto}
  .login{padding-inline:13px;font-size:13px}
  .lang{padding-inline:6px;font-size:12px;gap:4px}
  .lang svg{display:none}
  .panel,.card{padding:20px}
  .footer-links{column-gap:12px}
  .decoration{max-width:100%}
}
@media(max-width:359px){
  .brand{font-size:14px}
  .brand .logo{width:24px;height:24px}
  .login{padding-inline:10px}
  .lang{font-size:11px;padding-inline:4px}
  .topbar__end{gap:2px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}