:root{
  --bg:#E3EAF2;--bg-top:#EDF2F8;--bg-bottom:#DDE5EF;
  --panel:#F6F9FC;--panel-2:#D6DFEA;--border:#C6D1DE;
  --accent:#C86B2E;--accent-dark:#9A4E1B;--accent-light:#DC8A53;
  --steel:#6A88AB;--steel-deep:#34506F;
  --text:#131A24;--ink-2:#2A3647;--text-muted:#556273;--text-faint:#8592A3;
  --success:#2F8A5B;--warn:#B9851A;--error:#C23B3B;
  --tile-top:#F3F6FA;--tile-bottom:#E4EAF1;
  --edge-1:#D6DFEA;--edge-2:#D2DBE7;--edge-3:#CED8E4;--edge-4:#CAD4E1;--edge-5:#C6D1DE;--dot:#B6C2D0;
  --flag-red:var(--error);--flag-blue:#22386A;--flag-white:#FBFCFE;--flag-ring:rgba(19,26,36,.14);
  --hl:rgba(255,255,255,.92);--hl-soft:rgba(255,255,255,.55);--hl-faint:rgba(255,255,255,.28);--ink-hl:rgba(255,255,255,.16);
  --beam:rgba(255,255,255,.5);--beam-faint:rgba(255,255,255,.2);
  --glass:rgba(246,249,252,.72);--glass-strong:rgba(246,249,252,.84);--glass-low:rgba(228,235,244,.66);--sheen:rgba(255,255,255,.5);
  --accent-10:rgba(200,107,46,.10);--accent-14:rgba(200,107,46,.14);--accent-35:rgba(200,107,46,.35);--success-16:rgba(47,138,91,.16);
  --shadow-cool:rgba(38,56,82,.16);--shadow-cool-soft:rgba(38,56,82,.08);--shadow-ink:rgba(19,26,36,.30);
  --groove-in:rgba(19,26,36,.08);--tile-under:rgba(140,157,178,.28);--mesh-dot:rgba(85,98,115,.26);--line-soft:rgba(176,190,207,.55);
  --veil:rgba(19,26,36,.30);--clear:transparent;--grain-alpha:.03;
  --r-xs:6px;--r-s:9px;--r-button:10px;--r-platform:11px;--r-m:12px;--r-l:22px;--r-pill:999px;--r-circle:50%;
  --font-display:"Iowan Old Style",Georgia,"Songti SC","STSong","Noto Serif SC","Source Han Serif SC","Times New Roman",serif;
  --font-body:"Inter","Noto Sans SC",system-ui,-apple-system,"PingFang SC","Microsoft YaHei","Hiragino Sans GB",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
  --gutter:48px;--content-max:1280px;--header-height:72px;--anchor-gap:16px;--toc-height:64px;
  --shadow-panel:inset 0 1px 0 var(--hl),0 2px 6px var(--shadow-cool-soft),0 24px 60px -30px var(--accent-10);
  --ease: ease;--speed:.2s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-height) + var(--anchor-gap))}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img{max-width:100%;height:auto}
svg{flex-shrink:0;vertical-align:middle}
a{color:inherit;text-underline-offset:4px}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a,summary{touch-action:manipulation}
button:disabled{cursor:not-allowed}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--text);outline-offset:3px;border-radius:var(--r-xs)}
h1,h2,h3{font-weight:400;overflow-wrap:break-word;text-wrap:balance}
h1{font-family:var(--font-display);font-size:clamp(52px,4.45vw,64px);line-height:1.1;letter-spacing:-.02em}
h2{font-family:var(--font-display);font-size:clamp(30px,3.3vw,44px);line-height:1.2;letter-spacing:-.02em}
h3{font-size:21px;line-height:1.4}
p{margin:0 0 1.25em}
ul,ol{padding-left:1.4em}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--panel-2);border-radius:var(--r-m)}
pre code{overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
.wrap{width:100%;max-width:calc(var(--content-max) + var(--gutter)*2);padding-inline:var(--gutter);margin-inline:auto}
.section{padding-top:80px;padding-bottom:80px}
.section-head{max-width:760px;margin-bottom:32px}
.section-head h2{margin:0 0 16px}
.section-head p{color:var(--text-muted)}
.center{text-align:center;margin-inline:auto}
.mono{font-family:var(--font-mono)}
.muted{color:var(--text-muted)}
.no-break{white-space:nowrap}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-five{grid-template-columns:repeat(5,minmax(0,1fr))}
.panel,.card{min-width:0;padding:28px;border-radius:var(--r-l);background:var(--panel);box-shadow:var(--shadow-panel);border:1px solid var(--hl-soft)}
.groove{background:var(--panel-2);border-radius:var(--r-m);padding:24px;box-shadow:inset 0 1px 2px var(--groove-in)}
.decorated{position:relative;isolation:isolate;overflow-x:clip;max-width:100%}
.reveal{transition:opacity .35s ease,transform .35s ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:48px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status>*{min-width:0;max-width:100%}
#server-status + *{margin-top:24px}
.btn,.btn-primary,.btn-secondary,.login{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;white-space:nowrap;text-decoration:none;font-weight:600;min-height:44px}
.btn,.btn-primary,.btn-secondary{gap:10px;border:1px solid var(--clear);border-radius:var(--r-button);padding:11px 22px;font-size:15px;transition:transform var(--speed) var(--ease),box-shadow var(--speed) var(--ease)}
.btn-primary{height:48px;padding:0 20px 0 24px;background:linear-gradient(180deg,var(--ink-2),var(--text));color:var(--panel);letter-spacing:.01em;box-shadow:inset 0 1px 0 var(--ink-hl),0 2px 4px var(--shadow-cool-soft),0 12px 26px -12px var(--shadow-ink)}
.btn-primary svg{width:16px;height:16px}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);box-shadow:inset 0 1px 0 var(--ink-hl),0 3px 6px var(--shadow-cool-soft),0 16px 30px -12px var(--shadow-ink)}
.btn-primary:active,.btn-primary.is-active{transform:translateY(1px)}
.btn-primary:disabled,.btn-primary[aria-disabled="true"]{background:var(--panel-2);color:var(--text-muted);box-shadow:none;transform:none}
.btn-secondary{background:var(--panel);border-color:var(--border);color:var(--text);box-shadow:inset 0 1px 0 var(--hl)}
.btn-secondary:hover{background:var(--tile-top)}
.btn-text{display:inline-flex;align-items:center;gap:6px;min-height:24px;font-size:15px;font-weight:600;color:var(--text);text-decoration:none}
.btn-text span{color:var(--text-muted);transition:transform var(--speed) var(--ease)}
.btn-text:hover span{transform:translateX(2px)}
.cta-row{display:flex;align-items:center;flex-wrap:wrap;gap:16px 28px;margin-top:32px}
#site-header{position:relative;z-index:100;min-height:var(--header-height)}
.topbar{position:relative;z-index:103;display:flex;align-items:center;justify-content:space-between;flex-wrap:nowrap;gap:24px;height:var(--header-height)}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font-size:17px;font-weight:600;letter-spacing:-.01em;flex:none;white-space:nowrap}
.brand-mark{display:block;width:30px;height:30px;flex:none}
.brand-zh{font-weight:400;color:var(--text-muted)}
.nav{display:flex;align-items:center;min-width:0;flex:1;justify-content:center}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:4px;gap:2px;border-radius:var(--r-pill);background:var(--hl-faint);box-shadow:inset 0 0 0 1px var(--line-soft),inset 0 1px 0 var(--hl);backdrop-filter:blur(10px)}
.nav li{min-width:0}
.nav a{display:flex;align-items:center;justify-content:center;min-height:34px;padding:7px 13px;border-radius:var(--r-pill);font-size:14px;line-height:1.4;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--speed),background-color var(--speed)}
.nav a:hover{color:var(--text)}
.nav a[aria-current="page"]{background:var(--panel);color:var(--text);font-weight:600;box-shadow:inset 0 1px 0 var(--hl),0 1px 2px var(--shadow-cool-soft),0 6px 12px -6px var(--shadow-cool)}
.top-actions{display:flex;align-items:center;gap:6px;flex-shrink:0}
.lang-box{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;border-radius:var(--r-s);background:var(--clear);font-size:14px;color:var(--text-muted);cursor:pointer}
.lang span{white-space:nowrap}
.lang svg{width:15px;height:15px}
.lang:hover{color:var(--text)}
.lang-panel{position:absolute;top:calc(100% + 8px);right:0;z-index:110;min-width:172px;padding:8px;border:1px solid var(--border);border-radius:var(--r-m);background:var(--panel);box-shadow:var(--shadow-panel)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-xs);text-decoration:none;font-size:14px}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--panel-2)}
.login{height:38px;min-height:38px;padding:0 18px;border-radius:var(--r-s);background:var(--panel);color:var(--text);font-size:14px;box-shadow:inset 0 0 0 1px var(--border),inset 0 1px 0 var(--hl),0 4px 10px -6px var(--shadow-cool);transition:transform var(--speed)}
.login:hover{transform:translateY(-1px)}
.menu-btn{display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;padding:10px;border:0;border-radius:var(--r-s);background:var(--hl-soft);box-shadow:inset 0 0 0 1px var(--line-soft)}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.nav-drawer{position:fixed;z-index:102;top:var(--header-height);left:0;right:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);padding:20px var(--gutter) 40px}
.nav-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;border-radius:var(--r-s);text-decoration:none}
.nav-drawer a:hover,.nav-drawer a[aria-current="page"]{background:var(--panel-2)}
.drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
.drawer-languages a[aria-current="true"]{font-weight:600;background:var(--panel-2)}
.nav-veil{position:fixed;z-index:101;inset:var(--header-height) 0 0;background:var(--veil);border:0}
html.nav-open{overflow:hidden}
.site-footer{padding-top:56px;padding-bottom:24px;border-top:1px solid var(--line-soft);background:linear-gradient(180deg,var(--bg-bottom),var(--bg))}
.footer-grid{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:30em;margin-top:20px;color:var(--text-muted);font-size:14px}
.footer-title{font-size:14px;font-weight:600;margin:0 0 16px}
.footer-links{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 16px}
.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(--text-muted)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--text);text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:24px;padding-top:24px;border-top:1px solid var(--border);font-size:13px;color:var(--text-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.prose{max-width:800px;margin-inline:auto;overflow-wrap:break-word}
.prose h2{margin-top:56px;margin-bottom:24px}
.prose h3{margin-top:32px}
.prose li{margin-bottom:8px}
.prose blockquote{margin-inline:0}
.prose a{overflow-wrap:anywhere}
@media(min-width:1061px){.nav-drawer,.nav-veil{display:none!important}}
@media(max-width:1220px){.nav a{padding:7px 10px}.topbar{gap:16px}}
@media(max-width:1060px){.nav{display:none}.menu-btn{display:inline-flex}.top-actions{margin-left:auto}}
@media(max-width:768px){
  :root{--gutter:20px;--header-height:64px}
  h1{font-size:clamp(28px,8vw,40px)}
  .topbar{gap:12px}
  .section{padding-top:48px;padding-bottom:48px}
  .grid-three{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .panel,.card{padding:22px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt{transform:none}
  .decorated{max-width:100%;overflow-x:clip}
  .top-actions{gap:4px;margin-left:auto}
  .brand{font-size:15px;gap:7px}
  .lang{padding:0 6px}
  .lang span{display:none}
  .login{padding-inline:12px}
}
@media(max-width:360px){:root{--gutter:16px}.topbar{gap:6px}.brand-mark{width:26px;height:26px}.brand{font-size:14px}.login{padding-inline:10px}}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}