:root{
  --bg:#E5EBF5;
  --bg-panel:#F7F9FD;
  --bg-panel-2:#D8E1F0;
  --border:#C9D3E6;
  --accent:#E35A24;
  --accent-dark:#B8421A;
  --text:#172033;
  --text-muted:#56617A;
  --success:#1F8A5B;
  --warn:#B7791F;
  --error:#C43C3C;
  --hero-top:#EEF2FA;
  --hero-bottom:#DDE5F2;
  --paper:#FFFFFF;
  --wood-hi:#ECE6DC;
  --wood-lo:#DCD4C7;
  --metal-hi:#F0F3F8;
  --metal-mid:#CED5E0;
  --metal-lo:#A7B0C0;
  --bezel:#1B2233;
  --flag-red:#C9302C;
  --flag-blue:#22386A;
  --flag-white:#FFFFFF;
  --clear:transparent;
  --font-display:Georgia,"Times New Roman","Noto Serif SC","Source Han Serif SC","Songti SC","STSong","SimSun",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;
  --text-xs:12px;
  --text-sm:14px;
  --text-base:16px;
  --text-lg:20px;
  --text-xl:24px;
  --text-section:clamp(28px,3.2vw,40px);
  --text-display:clamp(52px,5vw,72px);
  --text-hero:66px;
  --weight-normal:400;
  --weight-medium:500;
  --weight-semibold:600;
  --weight-bold:700;
  --r-xs:3px;
  --r-s:6px;
  --r-m:10px;
  --r-l:16px;
  --r-pill:999px;
  --r-round:50%;
  --gutter:40px;
  --wrap:1200px;
  --header-height:64px;
  --anchor-offset:80px;
  --toc-offset:88px;
  --space-section:88px;
  --ease:200ms ease;
  --reveal-time:350ms;
  --tint-accent-10:color-mix(in srgb,var(--accent) 10%,var(--clear));
  --tint-accent-14:color-mix(in srgb,var(--accent) 14%,var(--clear));
  --tint-ink-08:color-mix(in srgb,var(--text) 8%,var(--clear));
  --hl-inner:inset 0 1px 0 color-mix(in srgb,var(--paper) 85%,var(--clear));
  --shadow-panel:0 32px 72px -28px var(--tint-accent-10),0 10px 24px -16px var(--tint-ink-08);
  --shadow-float:0 18px 44px -18px var(--tint-accent-14),0 4px 12px -8px var(--tint-ink-08);
  --shadow-device:0 40px 80px -36px var(--tint-accent-14),0 14px 30px -20px color-mix(in srgb,var(--text) 18%,var(--clear));
  --focus-ring:2px solid var(--accent-dark);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-offset)}
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}
h1,h2,h3,h4,p,figure,blockquote{margin:0}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-normal);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--text-display);line-height:1.15;letter-spacing:-.02em}
h2{font-size:var(--text-section);line-height:1.25}
h3{font-size:var(--text-xl);line-height:1.4}
p+p{margin-top:16px}
a{color:inherit;text-underline-offset:4px}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,a,input,select,textarea,summary{ -webkit-tap-highlight-color:var(--tint-accent-10)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:var(--focus-ring);outline-offset:3px;border-radius:var(--r-xs)}
button:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;opacity:.55}
.btn[aria-disabled="true"]{pointer-events:none}
img{display:block;max-width:100%;height:auto}
svg{vertical-align:middle;flex-shrink:0}
ul,ol{margin:0;padding:0;list-style:none}
[hidden]{display:none!important}
main,section,article,aside,nav,div,li{min-width:0}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--bg-panel-2);border-radius:var(--r-s);font-family:var(--font-mono)}
pre code{overflow-wrap:normal;white-space:pre}
table{border-collapse:collapse}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:var(--wrap);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--space-section);padding-bottom:var(--space-section)}
.section-head{max-width:760px;margin-bottom:40px}
.section-head p{margin-top:16px;color:var(--text-muted)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.eyebrow{margin:0 0 16px;font-family:var(--font-mono);font-size:var(--text-xs);line-height:16px;letter-spacing:.18em;text-transform:uppercase;color:var(--text-muted)}
.panel,.card{padding:32px;border:1px solid color-mix(in srgb,var(--paper) 85%,var(--border));border-radius:var(--r-m);background:var(--bg-panel);box-shadow:var(--shadow-panel),var(--hl-inner)}
.grid-two,.grid-three{display:grid;gap:24px}
.grid-two{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.decor-section{position:relative;overflow-x:clip}
.icon{width:24px;height:24px;flex-shrink:0}
.btn{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;height:48px;min-width:148px;padding:0 28px;border:0;border-radius:var(--r-s);font-size:var(--text-base);font-weight:var(--weight-semibold);white-space:nowrap;text-decoration:none;transition:background var(--ease),box-shadow var(--ease),color var(--ease)}
.btn-primary{color:var(--paper);background:linear-gradient(180deg,color-mix(in srgb,var(--accent) 72%,var(--accent-dark)) 0%,var(--accent-dark) 100%);box-shadow:0 14px 30px -14px color-mix(in srgb,var(--accent) 60%,var(--clear)),inset 0 1px 0 color-mix(in srgb,var(--paper) 25%,var(--clear))}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent-dark)}
.btn-ghost,.btn-secondary{color:var(--accent-dark);background:var(--paper);box-shadow:inset 0 0 0 1.5px var(--accent),0 10px 24px -16px var(--tint-accent-14)}
.btn-ghost:hover,.btn-secondary:hover,.btn-ghost.is-hover{background:color-mix(in srgb,var(--accent) 7%,var(--paper))}
.btn.is-focus{outline:var(--focus-ring);outline-offset:3px}
.btn-small{height:40px;min-width:0;padding-inline:18px;font-size:var(--text-sm)}
.cta-row{display:flex;flex-wrap:wrap;justify-content:center;gap:16px;margin-top:24px}
.topbar{position:relative;z-index:50;background:var(--paper);box-shadow:0 1px 0 var(--border),0 10px 28px -20px var(--tint-accent-14)}
.topbar-in{max-width:1320px;margin:0 auto;padding:0 var(--gutter);height:var(--header-height);display:flex;flex-wrap:nowrap;align-items:center;gap:32px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex-shrink:0}
.brand-mark{width:30px;height:30px;display:block}
.brand-en{font-weight:var(--weight-bold);font-size:18px;letter-spacing:-.01em;white-space:nowrap}
.brand-zh{font-size:13px;color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border);line-height:16px}
.nav{flex:1;min-width:0;display:flex;justify-content:center}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0}
.nav li{display:flex;align-items:center}
.nav li+li::before{content:"·";color:var(--border);margin:0 14px;font-weight:var(--weight-bold)}
.nav a{font-size:var(--text-sm);color:var(--text-muted);text-decoration:none;padding:6px 0;white-space:nowrap;transition:color var(--ease)}
.nav a:hover{color:var(--text)}
.nav a[aria-current="page"]{color:var(--text);font-weight:var(--weight-semibold);text-decoration:underline;text-decoration-thickness:1.5px;text-underline-offset:8px}
.tools{display:flex;align-items:center;gap:20px;flex-shrink:0}
.lang-select{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:32px;width:auto;background:none;border:0;padding:4px 0;font:inherit;font-size:var(--text-sm);color:var(--text-muted);cursor:pointer;white-space:nowrap;list-style:none}
.lang::-webkit-details-marker{display:none}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px;flex-shrink:0}
.lang:hover{color:var(--text)}
.lang-menu{position:absolute;top:calc(100% + 12px);right:0;z-index:70;min-width:176px;padding:8px;border:1px solid var(--border);border-radius:var(--r-s);background:var(--paper);box-shadow:var(--shadow-float)}
.lang-menu a{display:flex;align-items:center;min-height:40px;padding:8px 12px;text-decoration:none;font-size:var(--text-sm);border-radius:var(--r-xs)}
.lang-menu a:hover,.lang-menu a[aria-current="true"]{background:var(--bg)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:36px;padding:0 20px;border-radius:var(--r-s);background:var(--paper);box-shadow:inset 0 0 0 1.5px var(--accent);color:var(--accent-dark);font-size:var(--text-sm);font-weight:var(--weight-semibold);text-decoration:none;white-space:nowrap;transition:background var(--ease),color var(--ease)}
.btn-login:hover{background:var(--accent-dark);color:var(--paper);box-shadow:inset 0 0 0 1.5px var(--accent-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:8px;border:0;border-radius:var(--r-s);background:var(--bg-panel);color:var(--text)}
.menu-toggle svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round}
.mobile-drawer{display:none}
html.nav-open{overflow:hidden}
.site-footer{background:var(--bg-panel-2);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:56px;padding-top:56px;padding-bottom:48px}
.footer-brand p{margin-top:20px;max-width:360px;font-size:var(--text-sm);color:var(--text-muted)}
.footer-heading{font-family:var(--font-body);font-size:var(--text-sm);font-weight:var(--weight-semibold);margin-bottom:16px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 20px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;font-size:var(--text-sm);text-decoration:none}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;padding-top:24px;padding-bottom:32px;border-top:1px solid var(--border)}
.footer-languages,.footer-legal{display:flex;flex-wrap:wrap;gap:8px 20px}
.copyright{width:100%;font-size:var(--text-xs);color:var(--text-muted)}
.prose{max-width:820px;overflow-wrap:break-word}
.prose h2{margin-top:56px;margin-bottom:24px}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose p,.prose li{line-height:1.9}
.prose ul,.prose ol{padding-left:24px;margin-block:24px;list-style:revert}
.prose li+li{margin-top:8px}
.prose a{overflow-wrap:anywhere}
.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-height:180px;width:100%;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:32px}
@media(min-width:981px) and (max-width:1200px){
  .topbar-in{gap:20px;padding-inline:24px}
  .nav li+li::before{margin-inline:9px}
  .tools{gap:12px}
}
@media(max-width:980px){
  .nav{display:none}
  .tools{margin-left:auto;gap:12px}
  .menu-toggle{display:inline-flex}
  .topbar-in{gap:16px}
  .mobile-drawer{position:fixed;top:var(--header-height);left:0;right:0;z-index:45;display:block;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;padding:16px var(--gutter) 40px;background:var(--paper);border-top:1px solid var(--border)}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-bottom:1px solid var(--border);text-decoration:none}
  .mobile-drawer a[aria-current]{font-weight:var(--weight-semibold);background:var(--bg)}
  .drawer-languages{margin-top:24px}
  .drawer-label{font-size:var(--text-xs);color:var(--text-muted);padding:8px 16px}
}
@media(max-width:768px){
  :root{--gutter:24px;--space-section:56px;--text-display:clamp(28px,6vw,40px)}
  .grid-three{grid-template-columns:1fr}
  .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}
  .panel,.card{padding:24px}
  .decor-section{max-width:100%;overflow-x:clip}
  .tilt,.tilt-decor,[data-tilt]{transform:none}
  .topbar-in{gap:8px}
  .tools{gap:8px;margin-left:auto}
  .brand{gap:6px}
  .brand-en{font-size:var(--text-base)}
  .brand-mark{width:26px;height:26px}
  .btn-login{padding-inline:12px}
  .lang{font-size:var(--text-xs);gap:4px}
  .lang svg{display:none}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:0s!important;transition-duration:0s!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}