:root{
  --c-bg:#F5F5F7;--c-panel:#FFFFFF;--c-panel-2:#ECECF0;--c-border:#DCDCE2;--c-accent:#E5364C;--c-accent-dark:#B81F36;--c-coral:#FF7A59;
  --c-text:#1C1B20;--c-muted:#6B6A72;--c-success:#1F9D55;--c-warn:#C77D0A;--c-error:#B42318;--c-ink:#1C1B20;--c-on-ink:#FFFFFF;
  --c-notice:#E7E7EB;--c-mist:#FBEEF0;--c-mist-2:#F7E3E6;--c-cool:#E7E8ED;--c-cool-2:#DEE0E7;
  --c-graphite:#2F2F36;--c-graphite-2:#55565E;--c-silver:#C6C8D0;--c-silver-2:#E6E7EC;--c-steel:#9A9CA5;--c-frame-1:#FDFDFE;--c-frame-2:#D6D8E0;
  --clear:transparent;--t-accent-04:rgba(229,54,76,.04);--t-accent-06:rgba(229,54,76,.06);--t-accent-10:rgba(229,54,76,.10);--t-accent-14:rgba(229,54,76,.14);--t-accent-35:rgba(229,54,76,.35);
  --t-coral-07:rgba(255,122,89,.07);--t-coral-12:rgba(255,122,89,.12);--t-coral-22:rgba(255,122,89,.22);
  --t-white-20:rgba(255,255,255,.20);--t-white-35:rgba(255,255,255,.35);--t-white-50:rgba(255,255,255,.50);--t-white-82:rgba(255,255,255,.82);--t-white-95:rgba(255,255,255,.95);
  --t-ink-06:rgba(28,27,32,.06);--t-ink-08:rgba(28,27,32,.08);--t-ink-12:rgba(28,27,32,.12);--t-ink-16:rgba(28,27,32,.16);--t-ink-24:rgba(28,27,32,.24);
  --t-dot:rgba(28,27,32,.075);--t-dot-warm:rgba(184,31,54,.075);--t-success-12:rgba(31,157,85,.12);--t-success-24:rgba(31,157,85,.24);
  --flag-red:#D7263D;--flag-blue:#2C3E7A;--flag-gold:#F2C230;--flag-black:#1C1B20;--flag-white:#FFFFFF;
  --sh-sticker:0 22px 40px rgba(229,54,76,.10),0 3px 8px rgba(28,27,32,.06);
  --sh-panel:0 10px 28px -6px rgba(229,54,76,.10),0 1px 2px rgba(28,27,32,.05);
  --sh-cta:0 12px 26px -8px rgba(229,54,76,.45),inset 0 1px 0 rgba(255,255,255,.28);
  --sh-frame:inset 0 0 0 1px var(--t-white-95),0 0 0 1px var(--c-border),0 14px 24px -12px var(--t-ink-24);
  --sh-switch:inset 0 1px 2px var(--t-ink-16);--sh-knob:0 1px 3px var(--t-ink-24);
  --sh-small:0 1px 2px var(--t-ink-12);--sh-selected:0 6px 14px -8px var(--t-accent-35);
  --sh-route:0 4px 10px -4px var(--t-accent-35);--hl-inner:inset 0 1px 0 var(--t-white-95);
  --r-card:28px;--r-pill:999px;--r-sm:10px;--r-xs:6px;--r-flag:3px;--r-tiny:2px;--r-brand:9px;--r-row:7px;--r-circle:50%;
  --r-left:46px 34px 52px 40px/38px 50px 42px 56px;--r-center:40px 56px 44px 36px/52px 40px 48px 44px;--r-right:52px 38px 44px 58px/44px 54px 40px 48px;
  --r-bed-left:36px 24px 42px 30px/28px 40px 32px 46px;--r-bed-center:30px 46px 34px 26px/42px 30px 38px 34px;--r-bed-right:42px 28px 34px 48px/34px 44px 30px 38px;
  --r-lid:14px 14px 5px 5px;--r-deck:2px 2px 14px 14px;--r-notch:0 0 6px 6px;--r-mobile-screen:23px;--r-tablet:22px;--r-tablet-screen:15px;
  --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,monospace;
  --fs-9:9px;--fs-95:9.5px;--fs-10:10px;--fs-11:11px;--fs-12:12px;--fs-125:12.5px;--fs-13:13px;--fs-135:13.5px;--fs-14:14px;--fs-15:15px;--fs-16:16px;--fs-17:17px;--fs-18:18px;--fs-20:20px;--fs-24:24px;--fs-28:28px;
  --fs-h1:clamp(52px,5vw,64px);--fs-h2:clamp(28px,3.5vw,44px);--fs-h3:24px;--fs-mobile-h1:clamp(28px,7.8vw,38px);
  --gutter:32px;--wrap-width:1200px;--reading-width:840px;--section-space:96px;--nav-height:52px;--anchor-gap:76px;--toc-offset:12px;--toc-landing:88px;
  --ease:200ms ease;--reveal-time:550ms;--weight-body:400;--weight-medium:500;--weight-semibold:600;--weight-bold:700;--weight-display:800;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-gap);scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{margin:0;background:var(--c-bg);color:var(--c-text);font-family:var(--f-body);font-size:var(--fs-16);line-height:1.5;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
h1,h2,h3,h4,p,figure{margin:0}
h1,h2,h3{font-family:var(--f-display);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--fs-h1);font-weight:var(--weight-display);line-height:1.12;letter-spacing:-.02em}
h2{font-size:var(--fs-h2);font-weight:var(--weight-display);line-height:1.15;letter-spacing:-.02em}
h3{font-size:var(--fs-h3);font-weight:var(--weight-bold);line-height:1.3}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
a,button,summary,select,[role="tab"]{-webkit-tap-highlight-color:var(--t-accent-10)}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--c-text);outline-offset:3px}
button:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;background:var(--c-panel-2);color:var(--c-muted);box-shadow:none}
img{display:block;max-width:100%;height:auto}
svg{flex:none;flex-shrink:0;vertical-align:middle}
ul{list-style:none;margin:0;padding:0}
pre{max-width:100%;overflow-x:auto;padding:20px;border-radius:var(--r-sm);background:var(--c-panel-2);font-family:var(--f-mono);font-size:var(--fs-14);line-height:1.7}
code{font-family:var(--f-mono);overflow-wrap:anywhere}
pre code{overflow-wrap:normal;white-space:pre}
.wrap{max-width:var(--wrap-width);margin-inline:auto;padding-inline:var(--gutter);width:100%;min-width:0}
.reading-wrap{max-width:var(--reading-width);margin-inline:auto;padding-inline:var(--gutter);min-width:0}
.section{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.section-head{margin-bottom:32px}
.section-head p{margin-top:12px;color:var(--c-muted)}
.center{text-align:center}
.muted{color:var(--c-muted)}
.mono{font-family:var(--f-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}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.panel,.card{background:var(--c-panel);border:1px solid var(--t-white-95);border-radius:var(--r-card);box-shadow:var(--sh-panel),var(--hl-inner);padding:28px;min-width:0}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-two{grid-template-columns:repeat(2,minmax(0,1fr))}
.btn{display:inline-flex;align-items:center;justify-content:center;height:46px;padding:0 28px;border:0;border-radius:var(--r-pill);font-family:var(--f-body);font-size:var(--fs-16);font-weight:var(--weight-semibold);line-height:1;white-space:nowrap;flex-shrink:0;max-width:100%;transition:transform var(--ease),box-shadow var(--ease),background-color var(--ease)}
.btn-primary{color:var(--c-on-ink);background:linear-gradient(120deg,var(--c-accent) 0%,var(--c-accent) 42%,var(--c-coral) 128%);box-shadow:var(--sh-cta)}
.btn-primary:hover,.btn-primary.is-hover{background:linear-gradient(120deg,var(--c-accent-dark) 0%,var(--c-accent) 60%,var(--c-coral) 140%)}
.btn-primary:active,.btn-primary.is-pressed{transform:translateY(1px);box-shadow:var(--hl-inner)}
.btn-ghost,.btn-secondary{color:var(--c-text);border:1.5px solid var(--c-text);background:var(--t-white-50)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--c-panel)}
.btn-ink-lg{color:var(--c-on-ink);background:var(--c-ink)}
.btn-ink-lg:hover{background:var(--c-graphite-2)}
.btn-ink{display:inline-flex;align-items:center;justify-content:center;min-height:32px;padding:0 18px;border:0;border-radius:var(--r-pill);background:var(--c-ink);color:var(--c-on-ink);font-family:var(--f-body);font-size:var(--fs-13);font-weight:var(--weight-semibold);line-height:1;cursor:pointer;white-space:nowrap}
.btn-ink:hover{background:var(--c-graphite-2)}
.cta-row{display:flex;justify-content:center;align-items:center;flex-wrap:wrap;gap:14px;margin-bottom:18px}
.notice{background:var(--c-notice)}
.notice .wrap{display:flex;align-items:center;justify-content:space-between;gap:24px;min-height:48px}
.notice-text{font-size:var(--fs-125);line-height:1.5;color:var(--c-muted)}
.notice-text strong{color:var(--c-text);font-weight:var(--weight-semibold)}
.region-form{display:flex;align-items:center;gap:10px;margin:0;flex-shrink:0}
.select-wrap{position:relative;display:block;width:248px}
.select-wrap select{appearance:none;-webkit-appearance:none;width:100%;height:32px;padding:0 34px;border:1px solid var(--c-border);border-radius:var(--r-sm);background:var(--c-panel);font-family:var(--f-body);font-size:var(--fs-13);color:var(--c-text);box-shadow:var(--hl-inner);cursor:pointer}
.select-ic{position:absolute;top:9px;pointer-events:none;color:var(--c-text)}
.select-ic--l{left:12px}
.select-ic--r{right:12px;color:var(--c-muted)}
.site-nav{position:relative;z-index:30;background:var(--t-white-82);-webkit-backdrop-filter:saturate(1.6) blur(14px);backdrop-filter:saturate(1.6) blur(14px);border-bottom:1px solid var(--t-ink-06)}
.site-nav>.wrap{display:flex;align-items:center;height:var(--nav-height);gap:24px;position:relative}
.brand{flex:1 1 0;display:flex;align-items:center;gap:10px;min-width:0}
.brand-mark{width:30px;height:30px;border-radius:var(--r-brand);flex-shrink:0}
.brand-en{font-family:var(--f-display);font-size:var(--fs-17);font-weight:var(--weight-display);letter-spacing:-.01em;color:var(--c-text)}
.brand-zh{font-size:var(--fs-13);font-weight:var(--weight-medium);color:var(--c-muted);white-space:nowrap}
.nav-links{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:32px;font-size:var(--fs-135)}
.nav-links a{display:inline-flex;align-items:center;min-height:32px;color:var(--c-muted);font-weight:450;white-space:nowrap;transition:color var(--ease)}
.nav-links a:hover{color:var(--c-text)}
.nav-links a[aria-current="page"]{color:var(--c-text);font-weight:650}
.nav-tools{flex:1 1 0;display:flex;align-items:center;justify-content:flex-end;gap:18px}
.language-box{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;min-height:32px;width:auto;padding:0;border:0;background:none;font-family:var(--f-body);font-size:var(--fs-13);color:var(--c-text);cursor:pointer;white-space:nowrap}
.lang span{white-space:nowrap}
.lang svg{color:var(--c-muted)}
.language-menu{position:absolute;top:calc(100% + 10px);right:0;min-width:168px;padding:8px;border:1px solid var(--c-border);border-radius:var(--r-sm);background:var(--c-panel);box-shadow:var(--sh-panel);z-index:40}
.language-menu a{display:flex;align-items:center;min-height:36px;padding:6px 12px;border-radius:var(--r-xs);font-size:var(--fs-14)}
.language-menu a:hover,.language-menu a[aria-current="true"]{background:var(--c-panel-2)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:0;border:0;border-radius:var(--r-sm);background:var(--clear);color:var(--c-text)}
.mobile-drawer{display:none}
.nav-veil{position:fixed;inset:0;background:var(--t-ink-24);z-index:20;border:0;width:100%;height:100%}
[hidden]{display:none!important}
.site-footer{border-top:1px solid var(--c-border);background:linear-gradient(180deg,var(--c-panel-2),var(--c-bg));padding-top:64px;padding-bottom:32px;font-size:var(--fs-14)}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:48px}
.footer-brand{max-width:340px;min-width:0}
.footer-brand .brand{margin-bottom:18px}
.footer-brand p{color:var(--c-muted);line-height:1.8}
.footer-title{font-size:var(--fs-14);font-weight:var(--weight-semibold);margin-bottom:12px}
.footer-links{display:grid;gap:4px}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;color:var(--c-muted)}
.footer-links a:hover{color:var(--c-text);text-decoration:underline;text-underline-offset:4px}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px;padding-top:24px;border-top:1px solid var(--c-border)}
.footer-languages a{display:inline-flex;align-items:center;min-height:28px}
.footer-bottom{display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-top:20px;color:var(--c-muted);font-size:var(--fs-12)}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px}
.prose{line-height:1.85;overflow-wrap:break-word;min-width:0}
.prose p,.prose ul,.prose ol,.prose pre,.prose blockquote{margin-bottom:20px}
.prose h2{margin-top:48px;margin-bottom:20px;font-size:var(--fs-28)}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose a{ text-decoration:underline;text-underline-offset:4px}
.prose :not(pre)>code{background:var(--c-panel-2);padding:2px 5px;border-radius:var(--r-flag);font-size:.9em}
.prose section[id]{padding-top:12px}
.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}
.tilt,.decoration-host{overflow-x:clip}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:24px}
#server-status+*{margin-top:24px}
#server-status>*{min-width:0;max-width:100%}
[data-counter]{display:inline-block;min-width:3ch;font-variant-numeric:tabular-nums;font-family:var(--f-mono)}
@media(max-width:1100px){
  .nav-links{gap:20px}.brand-zh{display:none}.nav-tools{gap:12px}
}
@media(max-width:900px){
  .desktop-nav{display:none}.nav-tools{margin-left:auto;flex:0 0 auto}.menu-toggle{display:inline-flex}
  .site-nav>.wrap{gap:12px}
  .mobile-drawer:not([hidden]){display:block;position:absolute;top:100%;left:0;right:0;background:var(--c-panel);border-top:1px solid var(--c-border);box-shadow:var(--sh-panel);padding:16px var(--gutter) 24px;max-height:calc(100dvh - 100px);overflow-y:auto;overscroll-behavior:contain;z-index:35}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 12px;border-radius:var(--r-sm);font-size:var(--fs-16)}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current="page"]{background:var(--c-panel-2)}
  .drawer-languages{border-top:1px solid var(--c-border);margin-top:12px;padding-top:12px}
  .drawer-label{font-size:var(--fs-12);color:var(--c-muted);padding:8px 12px}
}
@media(max-width:768px){
  h1{font-size:var(--fs-mobile-h1)}
  .grid-three{grid-template-columns:1fr}
  .notice .wrap{gap:12px;flex-wrap:wrap;padding-top:10px;padding-bottom:10px}
  .notice-text{flex:1 1 100%}
  .region-form{width:100%}.select-wrap{flex:1;width:auto}
  .footer-grid{grid-template-columns:1fr 1fr;gap:32px}.footer-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:16px}
  .no-break{white-space:normal}
  .grid-two{grid-template-columns:1fr}
  .tilt{transform:none}
  .decoration-host{max-width:100%;overflow-x:clip}
  .nav-tools{gap:8px;margin-left:auto}
  .site-nav>.wrap{gap:8px}
  .language-box .lang{font-size:var(--fs-12)}
  .brand{gap:7px}.brand-en{font-size:var(--fs-15)}
  .btn{padding-inline:22px}
  .panel,.card{padding:24px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  .btn,.nav-links a{transition:none}
}