:root{
  --c-bg:#F4F5F3;
  --c-bg-top:#F8F9F7;
  --c-bg-bottom:#EEF1EE;
  --c-panel:#FFFFFF;
  --c-panel-2:#E9ECE9;
  --c-panel-soft:#F7F8F6;
  --c-border:#D6DBD7;
  --c-border-soft:#E4E8E5;
  --c-accent:#0A7F5C;
  --c-accent-dark:#075C43;
  --c-mint:#3FC99A;
  --c-mint-pale:#DDF3E9;
  --c-announce:#0B3B2E;
  --c-ink:#15201B;
  --c-muted:#56625C;
  --c-faint:#77827C;
  --c-success:#1E8E4E;
  --c-warn:#B7791F;
  --c-error:#C2362B;
  --c-on-dark:#FFFFFF;
  --c-on-dark-soft:rgba(255,255,255,.82);
  --c-accent-wash:rgba(10,127,92,.07);
  --c-accent-wash-2:rgba(10,127,92,.14);
  --c-accent-ring:rgba(10,127,92,.26);
  --c-grid:rgba(11,59,46,.04);
  --c-highlight:rgba(255,255,255,.95);
  --c-glow:rgba(255,255,255,.42);
  --c-btn-sheen:rgba(255,255,255,.18);
  --sh-tint:rgba(10,127,92,.12);
  --sh-tint-strong:rgba(10,127,92,.24);
  --sh-deep:rgba(7,92,67,.16);
  --sh-ink:rgba(21,32,27,.06);
  --mask-on:#000000;
  --flag-red:#C8313A;
  --flag-navy:#1F3473;
  --flag-white:#FFFFFF;
  --c-clear:transparent;
  --f-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --f-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --f-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,"Liberation Mono",monospace;
  --r-xs:4px;
  --r-sm:6px;
  --r-md:8px;
  --r-lg:18px;
  --r-xl:28px;
  --r-pill:999px;
  --r-round:50%;
  --sh-panel:0 0 0 1px var(--c-border),0 2px 6px -2px var(--sh-ink),0 18px 40px -16px var(--sh-tint);
  --sh-window:0 0 0 1px var(--c-border),0 2px 4px var(--sh-deep),0 32px 80px -20px var(--sh-tint),0 64px 120px -48px var(--sh-deep);
  --sh-float:0 0 0 1px var(--c-border),0 6px 14px -4px var(--sh-deep),0 26px 52px -18px var(--sh-tint-strong);
  --sh-chip:0 0 0 1px var(--c-border),0 3px 8px -3px var(--sh-tint);
  --gutter:32px;
  --content-width:1280px;
  --reading-width:800px;
  --fs-body:16px;
  --fs-small:14px;
  --fs-h1:64px;
  --fs-h2:40px;
  --fs-h3:24px;
  --weight-body:400;
  --weight-medium:500;
  --weight-strong:600;
  --leading-body:1.6;
  --leading-heading:1.2;
  --tracking-display:-.02em;
  --ease-ui:.16s;
  --toc-top:12px;
  --anchor-offset:88px;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;background:var(--c-bg);color:var(--c-ink);font-family:var(--f-body);font-size:var(--fs-body);font-weight:var(--weight-body);line-height:var(--leading-body);-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img,video{display:block;max-width:100%;height:auto}
svg{flex-shrink:0;max-width:100%}
h1,h2,h3,h4,p{overflow-wrap:break-word}
h1,h2,h3{font-family:var(--f-display);font-weight:var(--weight-body);letter-spacing:var(--tracking-display);line-height:var(--leading-heading);text-wrap:balance}
h1{font-size:clamp(52px,5vw,68px)}
h2{font-size:var(--fs-h2)}
h3{font-size:var(--fs-h3)}
p{margin:0 0 1.25em}
strong{font-weight:var(--weight-strong)}
small{font-size:var(--fs-small)}
code,kbd,pre{font-family:var(--f-mono)}
code{overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;border:1px solid var(--c-border);border-radius:var(--r-sm);background:var(--c-panel-soft)}
pre code{overflow-wrap:normal;white-space:pre}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--c-accent);outline-offset:3px}
[hidden]{display:none!important}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading-width);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:80px;padding-bottom:80px}
.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{min-width:0;padding:28px;background:var(--c-panel);border-radius:var(--r-md);box-shadow:var(--sh-panel),inset 0 1px 0 var(--c-highlight)}
.muted{color:var(--c-muted)}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:32px}
.section-head h2{margin:0}
.text-link{display:inline-flex;align-items:center;gap:6px;min-height:24px;padding-bottom:6px;font-size:15px;font-weight:var(--weight-medium);color:var(--c-ink)}
.text-link:hover{color:var(--c-accent-dark)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-width:168px;min-height:48px;padding:0 28px;border:0;border-radius:var(--r-sm);font-size:var(--fs-body);font-weight:var(--weight-medium);line-height:1.2;white-space:nowrap;flex-shrink:0;transition:transform var(--ease-ui),background-color var(--ease-ui),box-shadow var(--ease-ui)}
.btn-primary{background:var(--c-accent);color:var(--c-on-dark);box-shadow:inset 0 1px 0 var(--c-btn-sheen),0 10px 22px -10px var(--sh-deep)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--c-accent-dark);transform:translateY(-1px)}
.btn-ghost,.btn-secondary{background:var(--c-clear);color:var(--c-ink);box-shadow:inset 0 0 0 1.5px var(--c-ink)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--c-panel)}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--c-panel-2);color:var(--c-muted);box-shadow:inset 0 0 0 1px var(--c-border);transform:none}
.btn.is-focus{outline:2px solid var(--c-accent);outline-offset:3px}
.cta-row{margin-top:24px;display:flex;flex-wrap:wrap;justify-content:center;gap:12px}
.announce{background:var(--c-announce);color:var(--c-on-dark)}
.announce-inner{max-width:var(--content-width);margin:0 auto;padding:7px var(--gutter);display:flex;align-items:center;justify-content:center;gap:14px;font-size:13.5px;line-height:22px}
.announce-tag{flex:none;font-family:var(--f-mono);font-size:11px;font-weight:var(--weight-strong);letter-spacing:.14em;line-height:18px;padding:2px 10px 2px 12px;border-radius:var(--r-pill);background:var(--c-mint);color:var(--c-ink)}
.announce-text{color:var(--c-on-dark-soft)}
.announce-link{display:inline-flex;align-items:center;gap:4px;min-height:24px;font-weight:var(--weight-strong);color:var(--c-on-dark)}
.announce-link:hover{text-decoration:underline;text-underline-offset:3px}
.site-header{position:relative;z-index:20;background:var(--c-bg-top);border-bottom:1px solid var(--c-border-soft)}
.nav{max-width:var(--content-width);height:60px;margin:0 auto;padding:0 var(--gutter);display:flex;align-items:center;gap:36px}
.brand{display:inline-flex;align-items:center;gap:10px;font-size:18px;font-weight:var(--weight-strong);letter-spacing:.02em;color:var(--c-ink);flex-shrink:0}
.brand-mark{display:block;width:30px;height:30px;flex:none}
.brand-zh{font-size:var(--fs-small);font-weight:var(--weight-body);color:var(--c-muted)}
.nav-list{display:flex;align-items:center;gap:2px;list-style:none;margin:0;padding:0}
.nav-link{position:relative;display:inline-flex;align-items:center;gap:6px;height:36px;padding:0 12px;border:0;border-radius:var(--r-sm);background:var(--c-clear);font-size:14.5px;line-height:1;color:var(--c-muted);cursor:pointer;transition:color var(--ease-ui),background-color var(--ease-ui)}
.nav-link:hover{color:var(--c-ink);background:var(--c-accent-wash)}
.nav-link[aria-current="page"]{color:var(--c-ink)}
.nav-link[aria-current="page"]::after{content:"";position:absolute;left:12px;right:12px;bottom:3px;height:2px;border-radius:var(--r-xs);background:var(--c-accent)}
.caret{width:10px;height:10px;fill:none;stroke:currentColor;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round}
.nav-more,.lang-picker{position:relative}
.nav-menu,.language-menu{position:absolute;top:calc(100% + 10px);left:0;min-width:248px;margin:0;padding:6px;list-style:none;background:var(--c-panel);border-radius:var(--r-md);box-shadow:var(--sh-panel)}
.nav-menu a,.language-menu a{display:flex;flex-direction:column;gap:2px;min-height:44px;padding:9px 12px;border-radius:var(--r-sm);font-size:var(--fs-small);line-height:1.4;color:var(--c-ink)}
.nav-menu a:hover,.language-menu a:hover{background:var(--c-accent-wash)}
.nav-menu small{font-size:12px;color:var(--c-muted)}
.nav-menu a[aria-current],.language-menu a[aria-current]{color:var(--c-accent-dark);background:var(--c-accent-wash)}
.nav-more>summary{list-style:none}
.nav-more>summary::-webkit-details-marker{display:none}
.nav-tools{margin-left:auto;display:flex;align-items:center;gap:10px}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;height:36px;padding:0 10px;border:0;border-radius:var(--r-sm);background:var(--c-clear);font-size:var(--fs-small);white-space:nowrap;color:var(--c-muted);cursor:pointer}
.lang span{white-space:nowrap}
.lang:hover{color:var(--c-ink);background:var(--c-accent-wash)}
.language-menu{left:auto;right:0;min-width:180px;z-index:23}
.ico-line{display:block;width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:36px;min-width:64px;padding:0 18px;border-radius:var(--r-sm);background:var(--c-panel);box-shadow:inset 0 0 0 1.5px var(--c-ink);font-size:var(--fs-small);font-weight:var(--weight-medium);white-space:nowrap;color:var(--c-ink);transition:background-color var(--ease-ui),color var(--ease-ui)}
.btn-login:hover{background:var(--c-ink);color:var(--c-on-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid var(--c-border);border-radius:var(--r-sm);background:var(--c-panel)}
.mobile-drawer{display:none}
html.nav-open{overflow:hidden}
.site-footer{padding-top:64px;padding-bottom:28px;border-top:1px solid var(--c-border);background:var(--c-bg-bottom)}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:40px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:320px;color:var(--c-muted);font-size:var(--fs-small)}
.footer-title{margin:0 0 14px;font-size:var(--fs-small);font-weight:var(--weight-medium)}
.footer-links{display:flex;flex-direction:column;align-items:flex-start;gap:6px;list-style:none;margin:0;padding:0}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;font-size:var(--fs-small);color:var(--c-muted)}
.footer-links a:hover{color:var(--c-accent-dark);text-decoration:underline}
.footer-bottom{display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:40px;padding-top:20px;border-top:1px solid var(--c-border);font-size:13px;color:var(--c-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px}
.reveal{transition:opacity .6s,transform .6s}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:static;display:block;min-width:0;max-width:100%;min-height:120px;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:24px}
.prose{min-width:0}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose a{color:var(--c-accent-dark);text-decoration:underline;text-underline-offset:3px}
@media(max-width:1100px){
  .nav{gap:22px}
  .nav-link{padding-inline:9px}
  .footer-grid{gap:24px}
}
@media(max-width:900px){
  .desktop-nav{display:none}
  .nav-tools{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block;position:absolute;left:0;right:0;top:100%;z-index:22;max-height:calc(100dvh - 60px);overflow-y:auto;overscroll-behavior:contain;padding:16px var(--gutter) 24px;background:var(--c-panel);border-bottom:1px solid var(--c-border);box-shadow:var(--sh-panel)}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;border-radius:var(--r-sm);color:var(--c-ink)}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current]{background:var(--c-accent-wash);color:var(--c-accent-dark)}
  .mobile-languages{border-top:1px solid var(--c-border);margin-top:12px;padding-top:12px}
  .grid-five{grid-template-columns:repeat(3,minmax(0,1fr))}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  h1{font-size:clamp(28px,7vw,40px)}
  h2{font-size:32px}
  .grid-three{grid-template-columns:1fr}
  .sec{padding-top:48px;padding-bottom:48px}
  .section-head{align-items:flex-start;flex-direction:column;gap:16px}
  .announce-inner{font-size:12px;gap:8px;flex-wrap:wrap;padding-block:6px}
}
@media(max-width:640px){
  :root{--gutter:20px;--fs-h2:30px;--fs-h3:22px}
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .nav{gap:12px}
  .nav-tools{margin-left:auto;gap:6px}
  .lang{padding-inline:6px;font-size:12px}
  .btn-login{padding-inline:12px}
  .brand{gap:7px;font-size:16px}
  .brand-mark{width:28px;height:28px}
  .panel,.card{padding:22px}
  .footer-grid{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .announce-link{white-space:nowrap}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .nav{gap:8px}
  .brand{gap:5px;font-size:15px}
  .brand-mark{width:24px;height:24px}
  .lang{min-width:32px;padding-inline:3px}
  .nav-tools{gap:4px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}