:root{
  color-scheme:light;
  --bg:#F2F3F4;--bg-top:#F7F8F9;--bg-bottom:#ECEEF0;
  --panel:#FFFFFF;--panel-2:#E6E8EB;--border:#D9DCE0;
  --line:rgba(23,24,27,.07);--border-soft:rgba(23,24,27,.06);
  --accent:#C2601A;--accent-2:#E8A04A;--accent-dark:#8A4210;
  --accent-06:rgba(194,96,26,.06);--accent-08:rgba(194,96,26,.08);--accent-10:rgba(194,96,26,.10);--accent-14:rgba(194,96,26,.14);
  --text:#17181B;--muted:#5F636B;--faint:#8B9098;--wall:#A4A8AF;
  --success:#1F8A5B;--warn:#B7791F;--error:#C0392B;
  --ink-04:rgba(23,24,27,.04);--ink-06:rgba(23,24,27,.06);--ink-10:rgba(23,24,27,.10);--ink-16:rgba(23,24,27,.16);
  --white-hi:rgba(255,255,255,.95);--glass:rgba(255,255,255,.62);--glass-edge:rgba(255,255,255,.88);
  --beam-core:rgba(255,249,240,.92);--beam-soft:rgba(255,245,230,.46);
  --graphite:#2A2C31;--graphite-hi:#3B3E45;--graphite-2:#1D1F23;--graphite-3:#141518;
  --on-dark:#F4F5F6;--on-dark-muted:rgba(244,245,246,.6);--hi-dark:rgba(255,255,255,.14);
  --cap-top:#FFFFFF;--cap-top-2:#E7E8EA;--cap-side:#D3D5D9;--cap-side-2:#C3C6CB;--cap-rim:rgba(23,24,27,.05);
  --sheen:rgba(255,255,255,.6);--sheen-dark:rgba(255,255,255,.09);
  --tray-1:rgba(255,255,255,.86);--tray-2:rgba(236,238,241,.80);--tray-side:#DCDFE3;--tray-side-2:#CDD1D6;
  --flag-red:#C8323C;--flag-blue:#2E3566;--flag-white:#FFFFFF;--flag-edge:rgba(23,24,27,.14);
  --rb-1:#E8A04A;--rb-2:#D97A9C;--rb-3:#8E90DE;--rb-4:#5DB5AC;
  --veil:rgba(23,24,27,.32);
  --font-display:Georgia,"Times New Roman","Songti SC","STSong","Source Han Serif SC","Noto Serif CJK SC","SimSun",serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",Menlo,Consolas,"Liberation Mono",monospace;
  --r-6:6px;--r-8:8px;--r-10:10px;--r-12:12px;--r-pill:999px;--r-round:50%;
  --gutter:32px;--wrap-width:1304px;--header-height:72px;--anchor-space:96px;--toc-space:144px;
  --space-1:8px;--space-2:16px;--space-3:24px;--space-4:32px;--space-5:40px;--space-6:48px;--space-8:64px;--space-12:96px;
  --grain:.03;--lift:-6px;--drift:-4px;--s:1;
  --shadow-panel:inset 0 1px 0 var(--white-hi),0 16px 40px var(--accent-10),0 2px 6px var(--ink-06);
  --ease:cubic-bezier(.2,.7,.3,1);--duration-fast:.2s;--duration-reveal:.35s;
}
*,*::before,*::after{box-sizing:border-box}
/* Keep body clipping local so the rotated canvas beam cannot enlarge page overflow. */
html{overflow-x:clip;scroll-padding-top:var(--anchor-space);scroll-behavior:smooth}
html,body{margin:0;min-width:0}
body{background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img,video{max-width:100%;height:auto}
svg{flex-shrink:0}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
a{color:inherit;text-underline-offset:.2em}
button,a,summary,input,select,textarea{touch-action:manipulation}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
[hidden]{display:none!important}
h1,h2,h3,h4,p,ul,ol,blockquote{margin-top:0}
h1,h2,h3{font-family:var(--font-display);font-weight:400;line-height:1.2;letter-spacing:-.02em;overflow-wrap:break-word}
h1,.h1{font-size:clamp(52px,4.45vw,64px);line-height:1.12}
h2{font-size:clamp(28px,3vw,40px)}
h3{font-size:24px}
p{margin-bottom:var(--space-3)}
small{font-size:13px}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:var(--space-3);border-radius:var(--r-8);background:var(--panel-2)}
pre code{overflow-wrap:normal;white-space:pre}
table{border-collapse:collapse}
th,td{text-align:left}
:where(.wrap,.hero-grid,.card-grid,.footer-grid)>*{min-width:0}
.wrap{width:100%;max-width:var(--wrap-width);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--space-8);padding-bottom:var(--space-8)}
.section-head{max-width:720px;margin-bottom:var(--space-5)}
.reading-wrap{max-width:880px;margin-inline:auto}
.prose{min-width:0;overflow-wrap:break-word}
.prose h2{margin-top:var(--space-8);margin-bottom:var(--space-3)}
.prose h3{margin-top:var(--space-5);margin-bottom:var(--space-2)}
.prose li{margin-bottom:var(--space-1)}
.mono,.num{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.num{font-size:.92em;letter-spacing:-.01em}
.muted{color:var(--muted)}
.no-break{white-space:nowrap}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.panel,.card{min-width:0;padding:var(--space-4);border:1px solid var(--border-soft);border-radius:var(--r-12);background:var(--panel);box-shadow:var(--shadow-panel)}
.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--space-3)}
.btn,.btn-primary,.btn-secondary,.login{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;min-height:44px;text-decoration:none;white-space:nowrap}
.btn-primary{gap:10px;height:52px;padding:0 22px 0 28px;border:1px solid var(--graphite-3);border-radius:var(--r-pill);background:linear-gradient(180deg,var(--graphite-hi),var(--graphite));color:var(--on-dark);font-size:16px;font-weight:600;letter-spacing:.01em;box-shadow:inset 0 1px 0 var(--hi-dark),0 10px 24px var(--ink-16),0 20px 44px var(--accent-10);transition:transform var(--duration-fast) var(--ease)}
.btn-primary svg{width:18px;height:18px}
.btn-primary:hover{transform:translateY(-2px)}
.btn-primary:active{transform:translateY(1px)}
.btn-secondary{gap:8px;min-height:44px;padding:10px 20px;border:1px solid var(--border);border-radius:var(--r-pill);background:var(--panel);color:var(--text);font-weight:550;box-shadow:inset 0 1px 0 var(--white-hi)}
.btn-secondary:hover{border-color:var(--accent);background:var(--accent-06)}
.btn-text{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:32px;font-size:16px;font-weight:550;text-decoration:none;color:var(--text);transition:color var(--duration-fast) var(--ease)}
.btn-text svg{width:16px;height:16px;transition:transform var(--duration-fast) var(--ease)}
.btn-text:hover{color:var(--accent-dark)}
.btn-text:hover svg{transform:translateX(3px)}
:where(button,.btn-primary,.btn-secondary)[disabled],a[aria-disabled="true"]{opacity:.5;cursor:not-allowed;pointer-events:none}
.cta-row{display:flex;flex-wrap:wrap;align-items:center;gap:16px 32px;margin-top:36px}
.badge{display:inline-flex;align-items:center;gap:9px;min-height:32px;max-width:100%;padding:4px 14px 4px 15px;border:1px solid transparent;border-radius:var(--r-pill);background:linear-gradient(var(--panel),var(--panel)) padding-box,linear-gradient(100deg,var(--rb-1),var(--rb-2),var(--rb-3),var(--rb-4)) border-box;font-size:13px;color:var(--text);text-decoration:none;box-shadow:0 4px 16px var(--accent-08);transition:transform var(--duration-fast) var(--ease)}
.badge:hover{transform:translateY(-1px)}
.badge .sep{color:var(--faint)}
.badge .chev{color:var(--muted);font-size:15px;line-height:1}
.reveal{transition:opacity var(--duration-reveal) var(--ease),transform var(--duration-reveal) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-width:0;max-width:100%;overflow:hidden;margin-top:var(--space-4);margin-bottom:var(--space-4)}
#server-status+*{margin-top:var(--space-4)}
#server-status :where(.grid,.server-grid){min-width:0;max-width:100%}

/* Shared navigation */
#site-header,.masthead{position:relative;z-index:50;border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;flex-wrap:nowrap;gap:24px;min-height:var(--header-height)}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;color:var(--text);text-decoration:none;min-height:44px}
.brand img{display:block;width:32px;height:32px}
.brand-word{font-size:18px;font-weight:650;letter-spacing:-.015em}
.brand-zh{font-size:14px;color:var(--muted);font-weight:400}
.desktop-nav{flex:1;min-width:0;align-self:stretch}
.tabs{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px;height:100%}
.nav-more{position:relative;margin-left:auto}
.nav-more-toggle{display:flex;align-items:center;gap:6px;min-height:var(--header-height);padding-inline:9px;border:0;background:transparent;font-size:14px;color:var(--muted);cursor:pointer;white-space:nowrap}
.nav-more-toggle::after{content:"⌄"}
.nav-more-panel{position:absolute;right:0;top:100%;z-index:80;min-width:210px;padding:8px;border:1px solid var(--border);border-radius:var(--r-10);background:var(--panel);box-shadow:var(--shadow-panel)}
.tabs .nav-more-panel a{justify-content:flex-start;min-height:44px;padding:10px 12px}
.nav-more-panel a:hover{background:var(--accent-08)}
.tabs li{flex:none}
.tabs a{position:relative;display:flex;align-items:center;justify-content:center;min-height:var(--header-height);padding:0 13px;color:var(--muted);font-size:14.5px;text-decoration:none;white-space:nowrap;transition:color var(--duration-fast) var(--ease)}
.tabs a::after{content:"";position:absolute;left:13px;right:13px;bottom:0;height:2px;border-radius:var(--r-6);background:var(--accent);transform:scaleX(0);transition:transform .25s var(--ease)}
.tabs a:hover,.tabs a[aria-current="page"]{color:var(--text)}
.tabs a[aria-current="page"]{font-weight:550}
.tabs a[aria-current="page"]::after{transform:scaleX(1)}
.nav-end{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:7px;min-width:44px;width:auto;min-height:36px;padding:0 10px;border:0;border-radius:var(--r-8);background:transparent;font-size:14px;color:var(--muted)}
.lang span{white-space:nowrap}
.lang svg{width:15px;height:15px}
.lang:hover{background:var(--ink-04);color:var(--text)}
.lang-panel{position:absolute;top:calc(100% + 12px);right:0;z-index:80;min-width:184px;padding:8px;border:1px solid var(--border);border-radius:var(--r-10);background:var(--panel);box-shadow:var(--shadow-panel)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-6)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--accent-08);color:var(--accent-dark)}
.login{min-height:38px;padding:0 20px;border-radius:var(--r-pill);background:var(--panel);color:var(--text);font-size:14px;font-weight:600;box-shadow:inset 0 1px 0 var(--white-hi),0 0 0 1px var(--border),0 4px 14px var(--accent-08);transition:transform var(--duration-fast) var(--ease)}
.login:hover{transform:translateY(-1px)}
.menu-toggle{display:none;flex-direction:column;justify-content:center;align-items:center;gap:5px;min-width:44px;min-height:44px;padding:8px;border:1px solid var(--border);border-radius:var(--r-8);background:var(--panel);color:var(--text)}
.menu-line{display:block;width:20px;height:2px;background:currentColor;border-radius:var(--r-6)}
.mobile-drawer{display:none;position:fixed;z-index:60;top:var(--header-height);right:0;left:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);padding:var(--space-3) var(--gutter)}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-8);text-decoration:none}
.mobile-drawer a:hover,.mobile-drawer a[aria-current]{background:var(--accent-08);color:var(--accent-dark)}
.drawer-languages{margin-top:var(--space-3);padding-top:var(--space-2);border-top:1px solid var(--border)}
.nav-veil{position:fixed;z-index:40;inset:var(--header-height) 0 0;width:100%;height:calc(100dvh - var(--header-height));border:0;background:var(--veil)}
html.nav-open{overflow:hidden}
.skip-link{position:absolute;left:var(--gutter);top:8px;z-index:100;padding:8px 16px;transform:translateY(-160%);background:var(--panel);border-radius:var(--r-8);color:var(--text)}
.skip-link:focus{transform:none}

/* Porcelain canvas */
.canvas{position:relative;isolation:isolate;overflow:clip;overflow-x:clip;max-width:100%;background:linear-gradient(180deg,var(--bg-top) 0,var(--bg-bottom) 900px,var(--bg-bottom) 100%)}
.canvas::before{content:"";position:absolute;z-index:0;inset:0;max-width:100%;background:linear-gradient(128deg,transparent 38%,var(--beam-soft) 46%,var(--beam-core) 50%,var(--beam-soft) 54%,transparent 62%);pointer-events:none}
.grain{position:absolute;inset:0;z-index:1;width:100%;height:100%;opacity:var(--grain);pointer-events:none}
.page,.canvas>.masthead{position:relative;z-index:2}
.decoration-region{position:relative;overflow-x:clip;max-width:100%}
.tilt{transform:rotate(.45deg)}

/* Footer */
.site-footer{position:relative;border-top:1px solid var(--border);background:var(--bg-bottom);padding-top:var(--space-8);padding-bottom:var(--space-4)}
.footer-grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr) minmax(0,1fr);gap:var(--space-8)}
.footer-brand p{max-width:28em;color:var(--muted);font-size:14px;margin-top:var(--space-2)}
.footer-heading{font-family:var(--font-body);font-size:14px;font-weight:600;margin-bottom:var(--space-2)}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 16px;list-style:none;padding:0;margin:0}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;text-decoration:none;font-size:13px;color:var(--muted)}
.site-footer a:hover{color:var(--accent-dark)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:var(--space-5);padding-top:var(--space-3);border-top:1px solid var(--border)}
.footer-bottom{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;margin-top:var(--space-3);font-size:12px;color:var(--muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}

@media(max-width:1180px){
  .nav{gap:28px}
  .tabs a{padding-inline:9px;font-size:14px}
  .tabs a::after{left:9px;right:9px}
}
@media(max-width:1040px){
  .nav{gap:16px}
  .desktop-nav{display:none}
  .menu-toggle{display:flex}
  .nav-end{margin-left:auto}
  .mobile-drawer:not([hidden]){display:block}
  .footer-grid{gap:var(--space-4)}
}
@media(max-width:768px){
  h1,.h1{font-size:clamp(28px,6vw,40px)}
  .card-grid{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:640px){
  :root{--gutter:20px;--lift:-3px;--drift:-2px}
  .no-break{white-space:normal}
  .tilt{transform:none}
  .decoration-region{max-width:100%}
  .panel,.card{padding:var(--space-3)}
  .lang span{display:none}
  .nav{gap:8px}
  .nav-end{gap:6px;margin-left:auto}
  .brand{gap:7px}
  .brand-word{font-size:16px}
  .brand img{width:28px;height:28px}
  .login{padding-inline:14px}
  .section{padding-top:var(--space-6);padding-bottom:var(--space-6)}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .nav-end{gap:3px}
  .login{padding-inline:12px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  .btn-primary,.login,.badge,.btn-text svg,.tabs a::after{transition:none}
}