:root{
  --bg:#E6EDF5;--bg-panel:#F7FAFD;--bg-panel-2:#D8E2EE;--border:#C9D5E3;--border-soft:#DEE6F0;
  --accent:#F2B230;--accent-hi:#F7C65A;--accent-dark:#A66B05;--accent-wash:#FCEFD0;--accent-glow:#FFF8EA;
  --text:#0F2238;--text-muted:#4F6075;--text-faint:#6B7C90;
  --success:#1E8A5A;--success-wash:#DDF1E6;--warn:#C77A0A;--error:#C23B32;
  --ink:#102A43;--ink-hi:#1F4568;--ink-deep:#0A1E31;--ink-soft:#DCE5F0;
  --terra:#D9694A;--terra-soft:#F8E1D5;--terra-ink:#9C4127;
  --hero-top:#EEF3F9;--hero-bottom:#E1E9F3;--paper:#FFFFFF;
  --tint-blue:#2F6FCB;--tint-blue-bg:#DDE9F9;--tint-terra-bg:#FBE4D9;--tint-accent-bg:#FCEFCF;
  --tint-purple:#7647A6;--tint-purple-bg:#EEE4F6;--tint-cyan:#176D80;--tint-cyan-bg:#DDEFF3;
  --flag-red:#C8313A;--flag-blue:#24407C;--flag-green:#1D8A4E;--flag-white:#FFFFFF;
  --flag-edge:rgba(16,42,67,.18);--hl-top:rgba(255,255,255,.9);--hl-ring:rgba(255,255,255,.38);--glow-paper:rgba(255,255,255,.78);
  --veil:rgba(10,30,49,.45);--clear:transparent;
  --shadow-float:0 24px 48px -8px rgba(16,42,67,.12),0 4px 12px rgba(16,42,67,.07);
  --shadow-deep:0 28px 56px -14px rgba(4,14,26,.5),0 6px 16px rgba(4,14,26,.22);
  --shadow-window:0 0 0 1px var(--hl-ring),0 44px 80px -22px rgba(4,14,26,.62),0 16px 40px -10px rgba(16,42,67,.14);
  --shadow-cta:0 16px 30px -12px rgba(166,107,5,.55),inset 0 1px 0 rgba(255,255,255,.5);
  --shadow-card:0 22px 44px -20px rgba(16,42,67,.12),0 1px 2px rgba(16,42,67,.06);
  --shadow-recess:inset 0 1px 3px rgba(16,42,67,.10);
  --shadow-pick:0 0 0 1.5px var(--accent),0 10px 20px -12px rgba(166,107,5,.45);
  --r-board:40px;--r-xl:24px;--r-lg:20px;--r-win:18px;--r-md:12px;--r-sm:8px;--r-badge:10px;--r-icon:14px;--r-pill:999px;--r-circle:50%;
  --f-display:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Apple SD Gothic Neo','Microsoft YaHei',sans-serif;
  --f-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Malgun Gothic','Microsoft YaHei',system-ui,sans-serif;
  --f-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --gutter:40px;--wrap:1440px;--header-height:72px;--anchor-space:88px;--toc-space:152px;
  --size-body:16px;--size-small:14px;--size-h1:clamp(52px,4.45vw,64px);--size-h2:clamp(28px,3vw,40px);
  --ease:cubic-bezier(.2,.7,.2,1);--fast:.2s;--reveal-time:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-space);scroll-behavior:smooth}
body{margin:0;font-family:var(--f-body);font-size:var(--size-body);line-height:1.5;color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-underline-offset:3px}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a,summary{-webkit-tap-highlight-color:var(--clear)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent-dark);outline-offset:4px}
img{max-width:100%;height:auto;display:block}
svg{flex-shrink:0}
p{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4{font-family:var(--f-display);color:var(--text);text-wrap:balance}
h1{font-size:var(--size-h1);font-weight:800;line-height:1.1;letter-spacing:-.02em}
h2{font-size:var(--size-h2);font-weight:800;line-height:1.2;letter-spacing:-.02em}
h3{font-size:22px;line-height:1.35}
:where(main,article,section,nav,div,li){min-width:0}
.wrap{width:100%;max-width:var(--wrap);margin:0 auto;padding-inline:var(--gutter)}
.section{padding-top:72px;padding-bottom:72px}
.no-break{white-space:nowrap}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums;letter-spacing:-.01em}
.muted{color:var(--text-muted)}
.ico{flex:none;fill:none;stroke:currentColor;stroke-width:1.75;stroke-linecap:round;stroke-linejoin:round}
.ico-fill{flex:none;fill:currentColor}
.f-red{fill:var(--flag-red)}.f-white{fill:var(--flag-white)}.f-blue{fill:var(--flag-blue)}.f-green{fill:var(--flag-green)}.f-edge{fill:none;stroke:var(--flag-edge);stroke-width:1}
.flag{display:block;flex:none;border-radius:var(--r-sm);overflow:hidden}
.panel,.card{padding:28px;border-radius:var(--r-xl);background:var(--bg-panel);box-shadow:var(--shadow-card),inset 0 1px 0 var(--hl-top)}
.panel--recess{background:var(--bg-panel-2);box-shadow:var(--shadow-recess)}
.grid-three{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.stack{display:grid;gap:24px}
.prose{max-width:78ch;line-height:1.85;overflow-wrap:break-word}
.prose p,.prose ul,.prose ol,.prose pre,.prose blockquote{margin-block:20px}
.prose h2{margin-top:56px;margin-bottom:20px}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose ul{padding-left:24px;list-style:disc}
.prose ol{padding-left:28px;list-style:decimal}
code{font-family:var(--f-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--ink);color:var(--bg-panel);border-radius:var(--r-md)}
pre code{white-space:pre;overflow-wrap:normal}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;height:56px;padding:0 30px;border:0;border-radius:var(--r-pill);font-size:17px;font-weight:700;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--fast) var(--ease),background-color var(--fast) var(--ease),box-shadow var(--fast) var(--ease)}
.btn--primary,.btn-primary{color:var(--ink);background:linear-gradient(180deg,var(--accent-hi),var(--accent));box-shadow:var(--shadow-cta)}
.btn--primary:hover,.btn-primary:hover{transform:translateY(-1px)}
.btn--ghost{color:var(--ink);border:1.5px solid var(--ink);background:var(--clear);padding:0 28px}
.btn--ghost:hover{background:var(--ink-soft)}
.btn--small{height:44px;padding-inline:22px;font-size:var(--size-small)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none;cursor:not-allowed;transform:none}
.cta-row{display:flex;align-items:center;flex-wrap:wrap;gap:16px;margin-top:32px}
.topbar{position:relative;z-index:70;background:var(--hero-top)}
.topbar__inner{display:flex;align-items:center;flex-wrap:nowrap;gap:24px;height:var(--header-height)}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;flex:none}
.brand__mark{flex:none;width:34px;height:34px}
.brand__en{font-family:var(--f-display);font-weight:800;font-size:20px;letter-spacing:-.02em;color:var(--ink)}
.brand__zh{font-size:14px;font-weight:500;color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border)}
.menu{flex:1;min-width:0;display:flex;justify-content:center}
.menu__list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.menu a{display:inline-flex;align-items:center;gap:7px;height:38px;padding:0 12px;border-radius:var(--r-pill);font-size:14.5px;font-weight:600;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--fast),background-color var(--fast)}
.menu a:hover{color:var(--text);background:var(--bg-panel)}
.menu a.is-active{color:var(--ink);background:var(--bg-panel);box-shadow:var(--shadow-card)}
.topbar__tools{display:flex;align-items:center;gap:12px;flex-shrink:0;margin-left:auto}
.language{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;height:38px;padding:0 10px;border:0;background:var(--clear);border-radius:var(--r-pill);font-size:14px;font-weight:600;color:var(--text-muted);cursor:pointer;white-space:nowrap}
.lang:hover{color:var(--text);background:var(--bg-panel)}
.language__panel{position:absolute;right:0;top:calc(100% + 10px);z-index:95;min-width:180px;padding:8px;background:var(--paper);border:1px solid var(--border);border-radius:var(--r-lg);box-shadow:var(--shadow-float)}
.language__panel a{display:flex;align-items:center;min-height:44px;padding:10px 14px;border-radius:var(--r-sm);text-decoration:none;font-size:var(--size-small)}
.language__panel a:hover,.language__panel a[aria-current]{background:var(--hero-top)}
.login{display:inline-flex;align-items:center;justify-content:center;height:40px;padding:0 22px;border:1.5px solid var(--ink);border-radius:var(--r-pill);font-size:14.5px;font-weight:700;color:var(--ink);text-decoration:none;white-space:nowrap;transition:background-color var(--fast),color var(--fast)}
.login:hover{background:var(--ink);color:var(--paper)}
.nav-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:10px;border:1px solid var(--border);border-radius:var(--r-md);background:var(--bg-panel);color:var(--ink)}
.nav-toggle__icon{display:block;width:22px;height:22px}
.nav-drawer{display:none}
.nav-veil{display:none}
html.nav-open{overflow:hidden}
.site-footer{padding-top:56px;padding-bottom:32px;background:var(--bg-panel-2);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr .8fr;gap:40px}
.footer-brand p{max-width:30em;margin-top:20px;color:var(--text-muted);line-height:1.8}
.footer-heading{font-size:var(--size-small);font-weight:800;margin:0 0 16px}
.footer-links{display:grid;gap:4px}
.footer-links a{display:inline-flex;align-items:center;min-height:30px;padding-block:4px;color:var(--text-muted);font-size:var(--size-small);text-decoration:none}
.footer-links a:hover{color:var(--ink);text-decoration:underline}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:40px;padding-top:24px;border-top:1px solid var(--border);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(--reveal-time) var(--ease),transform var(--reveal-time) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status + *{margin-top:32px}
.decorated{position:relative;overflow-x:clip}
@media(max-width:1240px){
  .menu a{padding:0 9px;font-size:13.5px;gap:5px}
  .topbar__inner{gap:16px}
  .win__id-sub{display:none}
}
@media(max-width:1100px){
  .menu{display:none}
  .topbar__tools{margin-left:auto}
  .nav-toggle{display:inline-flex}
  .nav-drawer{position:fixed;top:var(--header-height);left:0;right:0;z-index:68;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:20px var(--gutter) 40px}
  .nav-open .nav-drawer{display:block}
  .nav-drawer a{display:flex;align-items:center;gap:12px;width:100%;min-height:48px;padding:12px 16px;text-decoration:none;border-radius:var(--r-md);font-weight:600}
  .nav-drawer a:hover,.nav-drawer a.is-active{background:var(--bg-panel-2)}
  .nav-drawer__languages{display:grid;margin-top:24px;padding-top:16px;border-top:1px solid var(--border)}
  .nav-veil{position:fixed;inset:var(--header-height) 0 0;z-index:65;background:var(--veil);border:0;width:100%}
  .nav-open .nav-veil{display:block}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--gutter:20px;--size-h1:38px;--size-h2:28px}
  .section{padding-top:48px;padding-bottom:48px}
  .brand__en{font-size:18px}
  .topbar__inner{gap:12px}
  .topbar__tools{gap:6px}
  .btn{height:52px;padding-inline:24px;font-size:16px}
  .btn--small{height:44px;font-size:var(--size-small)}
  .grid-three{grid-template-columns:minmax(0,1fr)}
  .footer-grid{gap:28px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .brand__zh{display:none}
  .tilt,.sheet,.win{transform:none}
  .decorated{max-width:100%}
  .panel,.card{padding:22px}
  .lang{font-size:12px;padding-inline:5px}
  .login{height:38px;padding-inline:14px;font-size:13px}
  .brand{gap:7px}
  .brand__mark{width:30px;height:30px}
  .brand__en{font-size:16px}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .topbar__inner{gap:6px}
  .topbar__tools{gap:3px}
  .lang{font-size:11px}
  .brand__en{font-size:15px}
  .brand__mark{width:27px;height:27px}
  .login{padding-inline:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}