:root {
  --bg:#FAFAF9;
  --panel:#FFFFFF;
  --panel-2:#F1F2F2;
  --border:#E3E5E6;
  --accent:#3A6B86;
  --accent-dark:#264C61;
  --mist:#5C8F8A;
  --text:#16191C;
  --text-hover:#2A2F34;
  --muted:#5F666C;
  --success:#2F8A5B;
  --warn:#B7791F;
  --error:#C2413A;
  --on-dark:#FFFFFF;
  --light-dot:#CDD2D5;
  --sky-top:#F4F6F6;
  --sky-bottom:#DCE6E9;
  --ridge-1:#C9D8DE;
  --ridge-1-lit:#DEE8EB;
  --ridge-2:#A9C2CC;
  --ridge-2-lit:#C4D5DC;
  --ridge-3:#7FA2B2;
  --ridge-3-lit:#9DB8C4;
  --sea-top:#E2EAED;
  --sea-bottom:#F1F4F4;
  --accent-03:rgba(58,107,134,.03);
  --accent-05:rgba(58,107,134,.05);
  --accent-10:rgba(58,107,134,.10);
  --accent-12:rgba(58,107,134,.12);
  --success-12:rgba(47,138,91,.14);
  --bg-fade-0:rgba(250,250,249,0);
  --bg-fade-60:rgba(250,250,249,.6);
  --white-0:rgba(255,255,255,0);
  --white-hi:rgba(255,255,255,.92);
  --white-50:rgba(255,255,255,.5);
  --veil:rgba(22,25,28,.32);
  --flag-red:#C8102E;
  --flag-white:#FFFFFF;
  --flag-navy:#1F2A5C;
  --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,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --font-mono-mix:"JetBrains Mono","Noto Sans SC","PingFang SC","Microsoft YaHei",ui-monospace,Menlo,Consolas,monospace;
  --weight-normal:400;
  --weight-medium:500;
  --size-body:16px;
  --size-small:14px;
  --size-display:clamp(52px,4.5vw,66px);
  --size-h2:36px;
  --size-h3:26px;
  --tracking-display:-.03em;
  --tracking-cjk:-.02em;
  --r:4px;
  --r-xs:2px;
  --r-tiny:1px;
  --r-round:50%;
  --shadow-panel:0 36px 80px -14px rgba(58,107,134,.12),0 12px 28px -8px rgba(58,107,134,.10);
  --shadow-chip:0 14px 30px -10px rgba(58,107,134,.16),0 2px 6px -2px rgba(58,107,134,.08);
  --shadow-cta:0 16px 36px -12px rgba(22,25,28,.28);
  --gutter:24px;
  --wrap:1280px;
  --hero-h:680px;
  --toc-offset:0px;
  --anchor-offset:88px;
  --ease: .2s ease;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;font-family:var(--font-body);font-size:var(--size-body);line-height:1.6;color:var(--text);background:linear-gradient(180deg,var(--accent-05) 0,var(--bg-fade-0) 920px),var(--bg);overflow-x:clip;-webkit-font-smoothing:antialiased}
[hidden]{display:none!important}
a{color:inherit;text-underline-offset:4px}
button,input,select,textarea{font:inherit}
button{color:inherit;cursor:pointer}
button:disabled{cursor:not-allowed}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-normal);text-wrap:balance}
h1{font-size:var(--size-display);line-height:1.12;letter-spacing:var(--tracking-cjk);margin:0 0 32px}
h2{font-size:var(--size-h2);line-height:1.25;letter-spacing:var(--tracking-cjk);margin:0 0 24px}
h3{font-size:var(--size-h3);line-height:1.3;margin:0 0 16px}
p{margin:0 0 20px}
ul,ol{padding-left:24px}
li+li{margin-top:6px}
strong,b{font-weight:var(--weight-medium)}
code{font-family:var(--font-mono-mix);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-xs)}
pre code{overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
.wrap{width:100%;max-width:var(--wrap);margin-inline:auto;padding-inline:var(--gutter);min-width:0}
.sec{padding-top:80px;padding-bottom:80px}
.prose{max-width:78ch;overflow-wrap:anywhere}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose li{margin-bottom:8px}
.no-break{white-space:nowrap}
.num{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.muted{color:var(--muted)}
.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))}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--r);box-shadow:var(--shadow-panel),inset 0 0 0 1px var(--white-hi);min-width:0}
.panel{padding:32px}
.card{padding:24px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:48px;padding:0 22px;border:1px solid transparent;border-radius:var(--r);font-size:16px;font-weight:var(--weight-medium);line-height:1;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:background-color var(--ease),color var(--ease)}
.btn svg{width:14px;height:14px}
.btn-primary{background:var(--text);color:var(--on-dark);box-shadow:var(--shadow-cta)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--text-hover)}
.btn-secondary{background:var(--panel-2);color:var(--text)}
.btn-secondary:hover,.btn-secondary.is-hover{background:var(--border)}
.btn-outline{background:var(--panel);border-color:var(--border);color:var(--text)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--panel-2);color:var(--muted);box-shadow:none}
.btn-sm{height:40px;padding-inline:16px;font-size:15px}
.btn-sm.btn-primary{box-shadow:none}
.btn-row,.cta-row{display:flex;flex-wrap:wrap;gap:12px}
.cta-row{margin-bottom:32px}
.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-height:120px;min-width:0;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:32px}
#site-header{position:relative;z-index:100}
.statusbar{background:linear-gradient(90deg,var(--accent-dark) 0%,var(--accent) 44%,var(--mist) 100%);color:var(--on-dark)}
.statusbar-inner{min-height:40px;display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:8px 20px;padding:6px 24px;font-size:14px;line-height:1.4}
.statusbar-text{margin:0}
.statusbar-text b{font-weight:var(--weight-medium)}
.statusbar-sep{opacity:.6;margin:0 8px}
.statusbar-link{display:inline-flex;align-items:center;min-height:24px;color:var(--on-dark);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:4px}
.statusbar-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:28px;padding:0 12px;background:var(--panel);color:var(--text);border-radius:var(--r);font-size:13px;font-weight:var(--weight-medium);text-decoration:none}
.statusbar-btn svg{width:12px;height:12px}
.masthead{display:flex;align-items:center;gap:32px;height:64px;padding:0 24px;position:relative;z-index:103}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;flex-shrink:0}
.brand img{width:30px;height:30px;flex-shrink:0}
.brand-word{font-family:var(--font-display);font-size:20px;font-weight:var(--weight-medium);letter-spacing:-.02em;white-space:nowrap}
.brand-zh{font-weight:var(--weight-normal);color:var(--muted)}
.tabs{flex:1;min-width:0}
.tabs ul{display:flex;align-items:center;justify-content:center;gap:0;list-style:none;margin:0;padding:0;border-bottom:1px solid var(--border)}
.tabs li{margin:0;flex-shrink:0}
.tabs a{position:relative;display:block;padding:10px 14px;font-size:15px;line-height:22px;color:var(--muted);text-decoration:none;white-space:nowrap;transition:color var(--ease)}
.tabs a:hover,.tabs a.is-active{color:var(--text)}
.tabs a.is-active::after{content:"";position:absolute;left:14px;right:14px;bottom:-1px;height:2px;background:linear-gradient(90deg,var(--accent),var(--mist))}
.masthead-end{display:flex;align-items:center;gap:8px;flex-shrink:0}
.lang-picker{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:36px;padding:0 12px;border:0;background:var(--panel-2);color:var(--text);border-radius:var(--r);font-size:14px;text-decoration:none;white-space:nowrap;width:auto}
.lang-caret{font-size:10px;color:var(--muted)}
.lang-panel{position:absolute;right:0;top:calc(100% + 8px);z-index:120;min-width:180px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r);box-shadow:var(--shadow-panel)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;white-space:nowrap}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--panel-2)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:36px;padding:0 18px;background:var(--text);color:var(--on-dark);border-radius:var(--r);font-size:14px;font-weight:var(--weight-medium);text-decoration:none;white-space:nowrap;transition:background-color var(--ease)}
.btn-login:hover{background:var(--text-hover)}
.nav-toggle{display:none;flex-direction:column;align-items:center;justify-content:center;gap:4px;min-width:44px;min-height:44px;padding:8px;background:var(--panel-2);border:0;border-radius:var(--r)}
.nav-toggle-line{display:block;width:20px;height:2px;background:currentColor}
.nav-toggle[aria-expanded="true"]{background:var(--border)}
.nav-drawer{display:none}
.nav-veil{display:none}
html.nav-open{overflow:hidden}
.site-footer{border-top:1px solid var(--border);background:var(--panel-2);padding-top:56px;padding-bottom:24px}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-intro{margin-top:20px;max-width:36ch;color:var(--muted)}
.footer-title{font-size:16px;font-weight:var(--weight-medium);margin-bottom:16px}
.footer-links{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links li{margin:0}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;font-size:14px;text-decoration:none}
.footer-links a:hover,.footer-legal a:hover{text-decoration:underline}
.footer-languages,.footer-legal{display:flex;flex-wrap:wrap;gap:8px 20px}
.footer-languages{margin-top:32px}
.footer-bottom{margin-top:32px;padding-top:20px;border-top:1px solid var(--border);display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;font-size:13px;color:var(--muted)}
.footer-bottom p{margin:0}
@media(max-width:1360px){.masthead{gap:20px}}
@media(max-width:1180px){
  .tabs a{padding:10px;font-size:14px}
  .tabs a.is-active::after{left:10px;right:10px}
  .masthead{gap:16px}
}
@media(max-width:1100px){
  .masthead{gap:12px}
  .tabs a{padding-inline:8px;font-size:13px}
}
@media(max-width:1024px){
  .masthead{height:64px}
  .masthead>.tabs{display:none}
  .masthead-end{margin-left:auto}
  .nav-toggle{display:flex}
  .nav-drawer{position:fixed;left:0;right:0;top:var(--header-edge,104px);height:calc(100dvh - var(--header-edge,104px));max-height:calc(100dvh - var(--header-edge,104px));z-index:102;background:var(--panel);padding:16px 24px 40px;overflow-y:auto;overscroll-behavior:contain}
  .nav-drawer:not([hidden]){display:block}
  .nav-drawer ul{list-style:none;margin:0;padding:0}
  .nav-drawer li{margin:0}
  .nav-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;text-decoration:none;border-bottom:1px solid var(--border)}
  .nav-drawer a.is-active{background:var(--panel-2);box-shadow:inset 3px 0 var(--accent)}
  .drawer-languages{margin-top:24px;border-top:1px solid var(--border)}
  .nav-veil{position:fixed;inset:var(--header-edge,104px) 0 0;z-index:101;background:var(--veil);border:0;width:100%;padding:0}
  .nav-veil:not([hidden]){display:block}
  .grid-five{grid-template-columns:repeat(3,minmax(0,1fr))}
  .preview-header .masthead{height:auto;min-height:64px;flex-wrap:wrap;padding-top:12px}
  .preview-header .masthead>.tabs{display:block;order:3;flex-basis:100%;overflow-x:auto}
  .preview-header .tabs ul{justify-content:flex-start;width:max-content;min-width:100%}
}
@media(max-width:768px){
  :root{--gutter:16px;--size-h2:28px;--size-h3:24px}
  h1{font-size:36px}
  .sec{padding-top:48px;padding-bottom:48px}
  .grid-three,.grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr;gap:32px}
  .statusbar-inner{font-size:13px;padding:8px 16px}
  .masthead{padding-inline:12px;gap:8px;flex-wrap:nowrap}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .grid-three,.grid-five{grid-template-columns:minmax(0,1fr)}
  .panel{padding:24px}
  .brand{gap:6px}
  .brand img{width:26px;height:26px}
  .brand-word{font-size:18px}
  .masthead-end{margin-left:auto;gap:6px}
  .lang{padding-inline:8px;font-size:12px}
  .btn-login{padding-inline:12px;font-size:13px}
  .nav-drawer{padding-inline:16px;max-width:100%}
  .footer-legal{gap:4px 16px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending{opacity:1;transform:none;transition:none}
  *,*::before,*::after{transition-duration:0s!important}
}