:root{
  --bg:#F8F8F7;
  --bg-panel:#FFFFFF;
  --bg-panel-2:#EFEFEC;
  --bg-porcelain:#F3F3F1;
  --bg-porcelain-deep:#E5E5E1;
  --border:#E4E3DF;
  --accent:#1E1D24;
  --accent-dark:#0C0B10;
  --glaze-hi:#2E2D35;
  --text:#17161B;
  --text-muted:#6B6A72;
  --text-faint:#94939B;
  --white:#FFFFFF;
  --success:#1F8A5B;
  --warn:#B7791F;
  --error:#C2382F;
  --ink-a00:rgba(30,29,36,0);
  --ink-a03:rgba(30,29,36,.03);
  --ink-a045:rgba(30,29,36,.045);
  --ink-a06:rgba(30,29,36,.06);
  --ink-a08:rgba(30,29,36,.08);
  --ink-a10:rgba(30,29,36,.10);
  --ink-a14:rgba(30,29,36,.14);
  --ink-a22:rgba(30,29,36,.22);
  --ink-a35:rgba(12,11,16,.35);
  --glaze-groove:rgba(12,11,16,.78);
  --glaze-line:rgba(255,255,255,.13);
  --glaze-text:rgba(255,255,255,.82);
  --glaze-rim:rgba(255,255,255,.10);
  --white-a00:rgba(255,255,255,0);
  --white-a60:rgba(255,255,255,.6);
  --white-a90:rgba(255,255,255,.9);
  --flag-white:#FFFFFF;
  --flag-sg-red:#EF3340;
  --flag-hk-red:#DE2910;
  --flag-jp-red:#BC002D;
  --flag-us-blue:#3C3B6E;
  --flag-us-red:#B22234;
  --flag-fr-blue:#0055A4;
  --flag-fr-red:#EF4135;
  --flag-it-green:#009246;
  --flag-it-red:#CE2B37;
  --flag-edge:rgba(30,29,36,.14);
  --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;
  --r-pill:999px;
  --r-card:10px;
  --r-chip:6px;
  --r-round:50%;
  --nav-h:64px;
  --gutter:32px;
  --content-width:1200px;
  --reading-width:800px;
  --text-base:16px;
  --text-small:14px;
  --text-h1:clamp(52px,4.45vw,64px);
  --text-h2:clamp(28px,3.2vw,44px);
  --text-h3:22px;
  --weight-regular:400;
  --weight-medium:500;
  --weight-brand:600;
  --section-space:96px;
  --ease-out:cubic-bezier(.2,.65,.3,1);
  --time-fast:.2s;
  --time-reveal:.35s;
  --hair:0 0 0 1px var(--ink-a06);
  --edge-hi:inset 0 1px 0 var(--white);
  --shadow-float:0 1px 2px var(--ink-a06),0 10px 22px -10px var(--ink-a14),0 26px 52px -14px var(--ink-a10);
  --shadow-panel:var(--hair),var(--edge-hi),0 28px 64px -24px var(--ink-a10);
  --ink-gradient:linear-gradient(180deg,var(--accent),var(--accent-dark));
  --focus-ring:2px solid var(--accent);
  --toc-offset:88px;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:80px;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-base);line-height:1.6;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img,video{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,a,input,select,textarea,summary{ -webkit-tap-highlight-color:var(--ink-a08)}
a{color:inherit;text-underline-offset:4px}
a,button,summary{touch-action:manipulation}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:var(--focus-ring);outline-offset:3px;border-radius:var(--r-chip)}
[hidden]{display:none!important}
h1,h2,h3,h4,p,ul,ol,blockquote,figure{margin-top:0}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-medium);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--text-h1);line-height:1.12;letter-spacing:-.02em;margin-bottom:32px}
h2{font-size:var(--text-h2);line-height:1.2;letter-spacing:-.015em;margin-bottom:24px}
h3{font-size:var(--text-h3);line-height:1.4;margin-bottom:16px}
p{margin-bottom:24px}
strong{font-weight:var(--weight-medium)}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;font-size:.9em;background:var(--bg-panel-2);border-radius:var(--r-chip);padding:2px 5px}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--accent-dark);color:var(--glaze-text);border-radius:var(--r-card)}
pre code{background:none;padding:0;overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
.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:var(--section-space);padding-bottom:var(--section-space)}
.stack>*+*{margin-top:24px}
.grid{display:grid;gap:24px}
.grid>* , .stage-grid>* , .footer-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}
.no-break{white-space:nowrap}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.panel,.card{min-width:0;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-panel);padding:28px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:0 24px;border:0;border-radius:var(--r-pill);font:var(--weight-medium) 15.5px/1.2 var(--font-body);text-align:center;text-decoration:none;transition:transform var(--time-fast) var(--ease-out),box-shadow var(--time-fast) var(--ease-out);flex-shrink:0;white-space:nowrap}
.btn svg{width:14px;height:14px}
.btn-ink,.btn-primary{color:var(--white);background:var(--ink-gradient);box-shadow:inset 0 1px 0 var(--glaze-rim),0 2px 4px var(--ink-a14),0 14px 28px -12px var(--ink-a35)}
.btn-ink:hover,.btn-primary:hover{transform:translateY(-1px);box-shadow:inset 0 1px 0 var(--glaze-rim),0 2px 4px var(--ink-a14),0 18px 32px -12px var(--ink-a35)}
.btn-line,.btn-secondary{color:var(--text);background:var(--bg-panel);box-shadow:inset 0 0 0 1px var(--border),0 1px 2px var(--ink-a06)}
.btn-line:hover,.btn-secondary:hover{box-shadow:inset 0 0 0 1px var(--ink-a22),0 6px 14px -8px var(--ink-a14)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;cursor:not-allowed;transform:none}
.btn-small{min-height:36px;padding-inline:18px;font-size:var(--text-small)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin:0 0 32px}
.text-link{display:inline-flex;align-items:center;min-height:28px;gap:8px;font-weight:var(--weight-medium)}
.site-head{position:relative;z-index:100;display:flex;align-items:center;gap:36px;height:var(--nav-h);max-width:1440px;margin:0 auto;padding:0 32px}
#site-header{position:relative;z-index:100}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;text-decoration:none;color:var(--text);min-height:36px}
.brand-mark{display:block;width:30px;height:30px;flex:none}
.brand-en{font:var(--weight-brand) 17px/1 var(--font-display);letter-spacing:-.015em}
.brand-zh{font:var(--weight-regular) 14px/1 var(--font-body);color:var(--text-muted)}
.nav{flex:1;min-width:0}
.nav-list{display:flex;align-items:center;gap:2px;margin:0;padding:0;list-style:none}
.nav-link{display:inline-flex;align-items:center;justify-content:center;min-height:34px;padding:0 14px;border-radius:var(--r-pill);font-size:14.5px;line-height:1.2;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--time-fast),background-color var(--time-fast)}
.nav-link:hover{color:var(--text)}
.nav-link[aria-current="page"]{color:var(--text);font-weight:var(--weight-medium);background:var(--bg-panel);box-shadow:var(--hair),var(--edge-hi),0 6px 14px -6px var(--ink-a14)}
.head-tools{position:relative;z-index:102;display:flex;align-items:center;gap:10px;flex-shrink:0;margin-left:auto}
.lang-box{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;height:36px;padding:0 14px;border:0;border-radius:var(--r-pill);background:var(--bg-panel);box-shadow:inset 0 0 0 1px var(--border);font:var(--weight-regular) 14px/1 var(--font-body);color:var(--text);cursor:pointer}
.lang svg{width:15px;height:15px;color:var(--text-muted)}
.lang-text{white-space:nowrap}
.lang-caret{font-size:11px;color:var(--text-muted)}
.lang-panel{position:absolute;z-index:110;top:calc(100% + 10px);right:0;min-width:176px;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)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:36px;padding:0 20px;border-radius:var(--r-pill);background:var(--ink-gradient);box-shadow:inset 0 1px 0 var(--glaze-rim),0 6px 14px -8px var(--ink-a35);font:var(--weight-medium) 14px/1 var(--font-body);color:var(--white);text-decoration:none;white-space:nowrap}
.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-pill);background:var(--bg-panel);color:var(--text)}
.menu-toggle svg{display:block;width:20px;height:20px}
.menu-stroke{fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.drawer{display:none;position:fixed;z-index:99;top:var(--nav-h);left:0;right:0;height:calc(100dvh - var(--nav-h));max-height:calc(100dvh - var(--nav-h));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:20px var(--gutter) 40px;border-top:1px solid var(--border)}
.drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;text-decoration:none;border-radius:var(--r-card)}
.drawer a[aria-current="page"],.drawer a:hover{background:var(--bg-panel-2)}
.drawer-languages{margin-top:24px;padding-top:16px;border-top:1px solid var(--border)}
.menu-veil{display:none;position:fixed;z-index:80;inset:var(--nav-h) 0 0;background:var(--ink-a35);border:0}
html.nav-open{overflow:hidden}
.site-footer{border-top:1px solid var(--border);background:linear-gradient(180deg,var(--bg-panel),var(--bg));padding-top:64px;padding-bottom:28px}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr 1fr;gap:48px}
.footer-intro{max-width:28em;color:var(--text-muted);margin-top:20px;font-size:var(--text-small)}
.footer-heading{font-size:var(--text-small);font-weight:var(--weight-medium);margin-bottom:16px}
.footer-links{display:grid;gap:8px;list-style:none;margin:0;padding:0}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;font-size:var(--text-small);color:var(--text-muted);text-decoration:none}
.footer-links a:hover{color:var(--text);text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;border-top:1px solid var(--border);padding-top:24px;margin-top:48px;font-size:13px;color:var(--text-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px}
.reveal{transition:opacity var(--time-reveal) var(--ease-out),transform var(--time-reveal) var(--ease-out)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
.prose{overflow-wrap:break-word}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:64px}
.prose h3{margin-top:32px}
.prose li+li{margin-top:10px}
.prose a{overflow-wrap:anywhere}
#server-status{display:block;position:relative;width:100%;min-width:0;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:24px}
#server-status+*{margin-top:24px}
#server-status>*{min-width:0;max-width:100%}
.decor-section,.fold{position:relative;isolation:isolate;overflow-x:clip;max-width:100%}
@media(min-width:961px) and (max-width:1320px){
  .site-head{gap:20px;padding-inline:24px}
  .nav-link{padding-inline:10px;font-size:13px}
  .head-tools{gap:8px}
}
@media(max-width:1100px){
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid-five{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media(max-width:960px){
  .site-head{gap:16px;padding-inline:20px;flex-wrap:nowrap}
  .nav{display:none}
  .head-tools{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .drawer.is-open{display:block}
  .menu-veil.is-open{display:block}
}
@media(max-width:768px){
  :root{--gutter:20px;--section-space:64px;--text-h1:clamp(28px,9vw,40px);--text-h2:30px}
  .grid-three,.grid-five{grid-template-columns:minmax(0,1fr)}
  .panel,.card{padding:24px}
  .footer-grid{gap:32px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.decor-tilt,[data-tilt]{transform:none}
  .decor-section,.fold{max-width:100%;overflow-x:clip}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
  .lang-text{display:none}
}
@media(max-width:380px){
  :root{--gutter:16px}
  .site-head{padding-inline:16px;gap:8px}
  .brand{gap:7px}
  .brand-mark{width:26px;height:26px}
  .brand-en{font-size:15px}
  .head-tools{gap:6px}
  .login{padding-inline:12px;font-size:13px}
  .lang{padding-inline:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:0s!important;animation-iteration-count:1!important;transition-duration:0s!important}
}