:root{
  --bg:#F6F5F2;--panel:#FFFFFF;--panel-2:#ECEAE5;--panel-soft:#FAF9F6;
  --border:#DDD9D1;--border-soft:#E8E5DF;--frame:#DDD9D1;
  --accent:#E2502F;--accent-dark:#B23A1E;--accent-soft:#F2B4A2;
  --text:#1D1915;--muted:#6B655D;--muted-2:#8C857B;
  --success:#2F8F5B;--warn:#C98A12;--error:#C8352B;
  --night:#1A140E;--night-card:#241C15;--night-line:#3A2F25;
  --umber:#2A1F17;--umber-92:rgba(42,31,23,.92);--umber-edge:rgba(255,245,235,.09);
  --on-dark:#F6F5F2;--on-dark-muted:#B8AEA2;
  --silver-1:#EDEBE6;--silver-2:#CFCBC3;--silver-3:#F5F4F0;--silver-deep:#BDB8AF;
  --silver-hl:rgba(255,255,255,.62);--brush-light:rgba(255,255,255,.26);--brush-dark:rgba(110,100,88,.07);
  --plate-edge:rgba(255,255,255,.55);
  --gauge-dim:#6A5D51;--gauge-mid:#B7B1A8;--gauge-hi:#F5F4F0;--gauge-track:rgba(255,245,235,.07);
  --tint-02:rgba(226,80,47,.02);--tint-055:rgba(226,80,47,.055);--tint-10:rgba(226,80,47,.10);--tint-14:rgba(226,80,47,.14);
  --ink-04:rgba(29,25,21,.04);--ink-08:rgba(29,25,21,.08);--ink-14:rgba(29,25,21,.14);--ink-28:rgba(29,25,21,.28);--ink-deep:rgba(26,20,14,.38);
  --hi-edge:rgba(255,255,255,.92);--frost:rgba(255,255,255,.66);--frost-edge:rgba(255,255,255,.86);
  --flag-red:#D33A2C;--flag-white:#FFFFFF;--flag-blue:#2A3E75;--flag-green:#2F8656;--flag-edge:rgba(29,25,21,.16);
  --clear:transparent;
  --r-xs:6px;--r-sm:8px;--r-md:12px;--r-route:10px;--r-ribbon:16px;--r-lg:18px;--r-card:20px;--r-xl:28px;--r-pill:999px;--r-round:50%;
  --font-display:"Iowan Old Style","Palatino Linotype",Georgia,"Noto Serif SC","Source Han Serif SC","Songti SC","STSong",serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",Consolas,"Liberation Mono",monospace;
  --text-xs:12px;--text-sm:14px;--text-base:16px;--text-lead:20px;
  --display:clamp(52px,4.8vw,68px);--heading:clamp(30px,3.4vw,44px);
  --gutter:32px;--page-width:1280px;--reading-width:840px;
  --space-1:8px;--space-2:16px;--space-3:24px;--space-4:32px;--space-5:48px;--space-6:64px;--space-7:88px;
  --nav-height:72px;--anchor-gap:88px;--toc-top:16px;--toc-clearance:96px;
  --ease:ease;--time:.2s;--reveal-time:.65s;
  --panel-shadow:inset 0 1px 0 var(--hi-edge),0 24px 56px -28px var(--tint-14);
}
*,*::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(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-base);line-height:1.6;-webkit-font-smoothing:antialiased}
body,main,section,article,aside,header,footer,nav,div{min-width:0}
a{color:inherit;text-underline-offset:3px}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,select{min-height:24px}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px}
::selection{background:var(--accent-soft);color:var(--text)}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:400;text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--display);line-height:1.12;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:var(--heading);line-height:1.2;letter-spacing:-.015em;margin:0 0 24px}
h3{font-size:28px;line-height:1.3;margin:0 0 16px}
p{margin:0 0 20px}
ul,ol{padding-inline-start:24px}
li+li{margin-top:6px}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;font-size:.9em;background:var(--panel-2);border-radius:var(--r-xs);padding:2px 5px}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-md);font-size:14px}
pre code{padding:0;white-space:pre;overflow-wrap:normal;background:var(--clear)}
table{border-collapse:collapse}
th,td{text-align:start;vertical-align:top}
.no-break{white-space:nowrap}
.muted{color:var(--muted)}
.eyebrow{font-size:13px;letter-spacing:.06em;color:var(--muted)}
.accent{color:var(--accent-dark)}
.wrap{width:100%;max-width:var(--page-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(--space-7);padding-bottom:var(--space-7)}
.page{max-width:100%;overflow-x:clip;background:linear-gradient(180deg,var(--tint-055) 0,var(--tint-02) 460px,var(--clear) 880px),var(--bg)}
.frame{max-width:var(--page-width);margin-inline:auto;border-inline:1px solid var(--frame)}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid>*{min-width:0}
.stack>*+*{margin-top:24px}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--panel-shadow);padding:32px}
.prose{line-height:1.85;overflow-wrap:break-word}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose li{padding-inline-start:4px}
.prose a{color:var(--accent-dark)}
.prose blockquote{margin-inline:0}
.btn,.btn-primary,.btn-secondary,.btn-ghost,.login{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:48px;padding:10px 24px;border:1px solid var(--text);border-radius:var(--r-pill);
  font-size:15px;font-weight:600;line-height:1.4;text-decoration:none;white-space:nowrap;flex-shrink:0;
  transition:background var(--time) var(--ease),color var(--time) var(--ease),transform var(--time) var(--ease)
}
.btn{background:var(--panel);color:var(--text)}
.btn-primary{background:var(--accent);border-color:var(--accent);color:var(--panel)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent-dark);border-color:var(--accent-dark)}
.btn-secondary,.btn-ghost{background:var(--clear);color:var(--text);border-color:var(--ink-28)}
.btn-secondary:hover,.btn-ghost:hover{background:var(--panel);border-color:var(--text)}
.btn:disabled,.btn[aria-disabled="true"],.btn-primary:disabled{cursor:not-allowed;background:var(--panel-2);color:var(--muted);border-color:var(--border)}
.btn.is-focus{outline:2px solid var(--accent-dark);outline-offset:3px}
.btn svg,.btn-primary svg{width:18px;height:18px}
.notice{display:flex;align-items:center;justify-content:center;gap:16px;min-height:40px;padding:8px 24px;background:var(--umber);color:var(--on-dark);font-size:13.5px;font-weight:500;letter-spacing:.01em;text-align:center}
.notice-sep{color:var(--on-dark-muted)}
.notice a{color:var(--accent-soft);text-decoration:underline;text-decoration-thickness:1px;white-space:nowrap;min-height:24px;display:inline-flex;align-items:center}
.notice a:hover{color:var(--panel)}
#site-header{position:relative;z-index:30}
.nav{display:flex;align-items:center;gap:32px;height:var(--nav-height);padding:0 40px;border-bottom:1px solid var(--frame);position:relative}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex-shrink:0;min-height:40px}
.brand-mark{display:block;width:32px;height:32px;filter:drop-shadow(0 6px 10px var(--tint-14))}
.brand-en{font-size:19px;font-weight:700;letter-spacing:.02em}
.brand-zh{font-size:14px;font-weight:400;color:var(--muted)}
.desktop-nav{height:100%;min-width:0}
.tabs{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px;height:100%}
.tabs li{margin:0;height:100%}
.tabs a{position:relative;display:flex;align-items:center;height:72px;padding:0 13px;font-size:15px;color:var(--muted);text-decoration:none;white-space:nowrap;transition:color var(--time) var(--ease)}
.tabs a:hover{color:var(--text)}
.tabs a[aria-current="page"]{color:var(--text);font-weight:600}
.tabs a[aria-current="page"]::after{content:"";position:absolute;left:13px;right:13px;bottom:-1px;height:2px;border-radius:var(--r-xs);background:var(--text)}
.nav-end{margin-left:auto;display:flex;align-items:center;gap:16px;flex-shrink:0}
.lang-wrap{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;height:40px;padding:0 8px;border:0;background:var(--clear);font-size:14px;color:var(--muted)}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px}
.lang:hover{color:var(--text)}
.lang-menu{position:absolute;right:0;top:calc(100% + 8px);width:192px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-md);box-shadow:var(--panel-shadow);z-index:42}
.lang-menu a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-sm);text-decoration:none}
.lang-menu a:hover,.lang-menu a[aria-current]{background:var(--panel-2)}
.login{height:40px;min-height:40px;padding:0 22px;background:var(--panel)}
.login:hover{background:var(--text);color:var(--panel)}
.menu-toggle{display:none;min-width:44px;min-height:44px;align-items:center;justify-content:center;border:1px solid var(--border);border-radius:var(--r-sm);background:var(--panel)}
.menu-toggle svg{width:22px;height:22px}
.mobile-drawer{display:none}
.menu-veil{position:fixed;inset:0;z-index:20;background:var(--ink-deep);border:0;border-radius:0}
.site-footer{border-top:1px solid var(--border);background:var(--panel-soft)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr 1fr;gap:40px;padding-top:56px;padding-bottom:40px}
.footer-brand p{color:var(--muted);font-size:14px;max-width:290px;margin-top:20px}
.footer-heading{font:600 14px var(--font-body);margin:0 0 16px}
.footer-links{list-style:none;margin:0;padding:0}
.footer-links li{margin:0}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;padding-block:4px;color:var(--muted);font-size:14px;text-decoration:none}
.footer-links a:hover{color:var(--accent-dark);text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;border-top:1px solid var(--border);padding-top:24px;padding-bottom:32px;font-size:13px;color:var(--muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.footer-legal a{display:inline-flex;min-height:24px;align-items:center}
.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:120px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:32px}
.decor-zone{position:relative;overflow-x:clip;max-width:100%}
.defs{position:absolute;width:0;height:0;overflow:hidden}
@media(max-width:1240px){
  .nav{gap:20px;padding-inline:24px}
  .tabs a{padding-inline:9px;font-size:14px}
  .nav-end{gap:8px}
}
@media(max-width:1100px){
  .nav{height:72px}
  .desktop-nav{display:none}
  .nav-end{margin-left:auto}
  .menu-toggle{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block;position:absolute;inset:100% 0 auto;z-index:40;background:var(--panel);padding:16px 24px 24px;border-bottom:1px solid var(--border);max-height:calc(100dvh - 112px);overflow-y:auto;overscroll-behavior:contain;box-shadow:var(--panel-shadow)}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;text-decoration:none;border-radius:var(--r-sm)}
  .mobile-drawer a[aria-current="page"]{background:var(--panel-2);font-weight:600}
  .drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--gutter:24px;--display:40px;--heading:32px;--space-7:56px}
  h1{font-size:40px;line-height:1.15}
  .grid{grid-template-columns:minmax(0,1fr)}
  .panel,.card{padding:24px}
}
@media(max-width:640px){
  :root{--gutter:20px}
  .no-break{white-space:normal}
  .tilt,.decor-tilt,[data-tilt]{transform:none}
  .decor-zone,.decor-zone>*{max-width:100%}
  .notice{gap:6px 12px;flex-wrap:wrap;padding:8px 16px;font-size:12px}
  .nav{padding-inline:16px;gap:8px}
  .nav-end{margin-left:auto;gap:6px}
  .brand{gap:7px}
  .brand-en{font-size:17px}
  .brand-mark{width:28px;height:28px}
  .lang{padding-inline:4px;font-size:12px;gap:3px}
  .login{padding-inline:14px;font-size:14px}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:24px}
  .footer-bottom{display:block}
  .footer-legal{margin-top:16px}
  pre{padding:16px}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .nav{padding-inline:12px}
  .brand-en{font-size:16px}
  .nav-end{gap:4px}
  .lang svg{display:none}
  .login{padding-inline:12px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:0s!important;animation-duration:0s!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}