:root {
  --bg:#FAF9F7;
  --bg-panel:#FFFFFF;
  --bg-panel-2:#F2F0EC;
  --border:#E7E3DD;
  --edge:rgba(231,227,221,.85);
  --accent:#F0681A;
  --accent-dark:#C24F0C;
  --accent-deep:#D9580F;
  --accent-soft:#FDDCC6;
  --accent-glow:rgba(240,104,26,.06);
  --accent-wash:rgba(240,104,26,.11);
  --accent-shadow:rgba(240,104,26,.10);
  --accent-shadow-strong:rgba(240,104,26,.34);
  --sky:#4E9BF2;
  --sky-soft:#D4E6FC;
  --sky-glow:rgba(78,155,242,.05);
  --sky-wash:rgba(78,155,242,.13);
  --sky-tint-04:rgba(78,155,242,.04);
  --sky-tint-10:rgba(78,155,242,.10);
  --sky-tint-12:rgba(78,155,242,.12);
  --sky-top:#FFFFFF;
  --sky-bottom:#F4F2EE;
  --mountain-far:#B8D8FA;
  --mountain-mid:#86B9F2;
  --mountain-near:#4E9BF2;
  --text:#1C1B19;
  --text-muted:#65615A;
  --success:#2E9E5B;
  --success-tint:rgba(46,158,91,.11);
  --success-ring:rgba(46,158,91,.18);
  --warn:#D9930F;
  --error:#D63A2F;
  --highlight:rgba(255,255,255,.95);
  --btn-sheen:rgba(255,255,255,.24);
  --ink-shadow:rgba(28,27,25,.06);
  --ink-shadow-soft:rgba(28,27,25,.04);
  --veil:rgba(28,27,25,.26);
  --flag-red:#D52B1E;
  --flag-blue:#1D3C8F;
  --flag-white:#FFFFFF;
  --clear:transparent;
  --radius-xl:28px;
  --radius-lg:20px;
  --radius-md:14px;
  --radius-sm:8px;
  --radius-pill:999px;
  --radius-round:50%;
  --radius-corner:16px 10px 10px 4px;
  --radius-curtain:40px 40px 0 0;
  --radius-line:3px;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SF Mono",Menlo,Consolas,monospace;
  --body-size:17px;
  --hero-size:68px;
  --h1-size:clamp(52px,5vw,72px);
  --h2-size:clamp(28px,3vw,40px);
  --h3-size:23px;
  --small-size:14px;
  --display-weight:800;
  --bold-weight:700;
  --medium-weight:600;
  --body-weight:400;
  --hero-tracking:-.03em;
  --heading-tracking:-.02em;
  --gutter:32px;
  --content-width:1200px;
  --header-width:1312px;
  --header-height:88px;
  --anchor-offset:104px;
  --toc-offset:168px;
  --section-space:80px;
  --shadow-panel:0 24px 56px -24px var(--accent-shadow-strong),0 2px 6px var(--ink-shadow-soft),inset 0 1px 0 var(--highlight);
  --shadow-pill:0 10px 28px -14px var(--accent-shadow-strong),0 1px 2px var(--ink-shadow);
  --ease:ease;
  --fast:.2s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--body-size);font-weight:var(--body-weight);line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
img,svg{vertical-align:middle;max-width:100%}
img{height:auto}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
a{color:inherit;text-underline-offset:.2em}
button,a,summary{-webkit-tap-highlight-color:var(--accent-wash)}
:focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px;border-radius:var(--radius-sm)}
[hidden]{display:none!important}
h1,h2,h3{font-family:var(--font-display);line-height:1.2;letter-spacing:var(--heading-tracking);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--h1-size);font-weight:var(--display-weight);line-height:1.12;margin:0 0 24px}
h2{font-size:var(--h2-size);font-weight:var(--display-weight);margin:0 0 24px}
h3{font-size:var(--h3-size);font-weight:var(--bold-weight);margin:0 0 16px}
p{margin:0 0 20px}
ul,ol{padding-inline-start:24px}
li+li{margin-top:6px}
strong{font-weight:var(--bold-weight)}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;background:var(--bg-panel-2);border-radius:var(--radius-sm);padding:2px 5px}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:24px;border:1px solid var(--border);border-radius:var(--radius-md);background:var(--bg-panel-2)}
pre code{padding:0;white-space:pre;overflow-wrap:normal}
table{border-collapse:collapse}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.panel{min-width:0;background:var(--bg-panel);border:1px solid var(--edge);border-radius:var(--radius-xl);padding:32px;box-shadow:var(--shadow-panel)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.center{text-align:center}
.prose{max-width:800px;min-width:0}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose a{color:var(--accent-dark);overflow-wrap:anywhere}
.prose img{max-width:100%}
.prose li{padding-inline-start:4px}
.skip{position:absolute;left:16px;top:-80px;z-index:100;padding:8px 16px;border-radius:var(--radius-pill);background:var(--text);color:var(--bg-panel);font-size:var(--small-size);text-decoration:none}
.skip:focus{top:12px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:52px;padding:0 28px;border:1px solid var(--clear);border-radius:var(--radius-pill);font-family:var(--font-body);font-size:18px;font-weight:var(--bold-weight);letter-spacing:-.005em;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--fast) var(--ease),box-shadow var(--fast) var(--ease),background-color var(--fast) var(--ease)}
.btn-primary{padding:0 22px 0 30px;color:var(--bg-panel);background:linear-gradient(180deg,var(--accent),var(--accent-deep));box-shadow:0 14px 28px -12px var(--accent-shadow-strong),inset 0 1px 0 var(--btn-sheen)}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);background:var(--accent-dark);box-shadow:0 18px 32px -12px var(--accent-shadow-strong),inset 0 1px 0 var(--btn-sheen)}
.btn-primary:active{transform:translateY(0)}
.btn-ghost,.btn-secondary{background:var(--bg-panel-2);color:var(--text);font-weight:var(--medium-weight)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--border)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none;cursor:not-allowed;transform:none}
.btn-arrow{width:20px;height:20px;flex:none;fill:none;stroke:var(--bg-panel);stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}
.cta-row{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin-top:24px}
#site-header{position:relative;z-index:60;min-height:var(--header-height)}
.topbar{max-width:var(--header-width);margin:0 auto;padding:16px 32px 0;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;column-gap:24px;min-height:72px;position:relative;z-index:63}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;justify-self:start;flex-shrink:0}
.brand img{width:36px;height:36px;flex:none}
.brand-word{font-family:var(--font-display);font-weight:var(--display-weight);font-size:21px;letter-spacing:var(--heading-tracking);color:var(--text)}
.brand-zh{color:var(--text-muted);font-weight:var(--medium-weight)}
.tabs{min-width:0}
.tabs ul{display:flex;align-items:center;list-style:none;margin:0;padding:4px 8px;background:var(--bg-panel);border:1px solid var(--edge);border-radius:var(--radius-pill);box-shadow:var(--shadow-pill);gap:0}
.tabs li{margin:0;flex-shrink:0}
.tabs a{position:relative;display:block;padding:0 14px;line-height:44px;font-size:15px;font-weight:500;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--fast) var(--ease)}
.tabs a::after{content:"";position:absolute;left:14px;right:14px;bottom:5px;height:3px;border-radius:var(--radius-line);background:var(--accent);transform:scaleX(0);opacity:0;transition:transform .25s var(--ease),opacity .25s var(--ease)}
.tabs a:hover{color:var(--text)}
.tabs a:hover::after{transform:scaleX(.45);opacity:.35}
.tabs a.is-active{color:var(--text);font-weight:var(--bold-weight)}
.tabs a.is-active::after{transform:scaleX(1);opacity:1}
.top-actions{display:flex;align-items:center;gap:8px;justify-self:end;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 12px;border:0;border-radius:var(--radius-pill);background:var(--clear);color:var(--text-muted);font-size:15px;font-weight:500;white-space:nowrap}
.lang:hover{background:var(--bg-panel-2);color:var(--text)}
.lang svg{width:17px;height:17px;flex:none}
.lang-text{white-space:nowrap}
.caret{font-size:12px}
.lang-panel{display:none;position:absolute;right:0;top:calc(100% + 8px);z-index:80;min-width:184px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius-lg);box-shadow:var(--shadow-panel)}
.lang-wrap.is-open .lang-panel{display:block}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 14px;text-decoration:none;font-size:15px;border-radius:var(--radius-md)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--bg-panel-2);color:var(--accent-dark)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 20px;border:1.5px solid var(--text);border-radius:var(--radius-pill);background:var(--bg-panel);color:var(--text);font-size:15px;font-weight:var(--bold-weight);text-decoration:none;white-space:nowrap}
.login:hover{background:var(--text);color:var(--bg-panel)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;padding:10px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--bg-panel);color:var(--text)}
.menu-line{display:block;width:20px;height:2px;background:currentColor;border-radius:var(--radius-line)}
.menu-toggle[aria-expanded="true"] .menu-line:first-child{transform:translateY(6px) rotate(45deg)}
.menu-toggle[aria-expanded="true"] .menu-line:nth-child(2){opacity:0}
.menu-toggle[aria-expanded="true"] .menu-line:last-child{transform:translateY(-6px) rotate(-45deg)}
.mobile-drawer{display:none}
.nav-veil{display:none}
html.nav-open{overflow:hidden}
.ico{width:15px;height:15px;flex:none;fill:none;stroke:currentColor;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round}
.site-footer{background:var(--bg-panel);border-top:1px solid var(--border);padding-top:56px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px}
.footer-grid>*{min-width:0}
.footer-brand p{color:var(--text-muted);font-size:15px;margin-top:20px;max-width:300px}
.footer-title{font-size:16px;font-weight:var(--bold-weight);margin:0 0 14px}
.footer-links{display:grid;gap:4px}
.footer-links a{display:block;padding:5px 0;min-height:30px;font-size:14px;text-decoration:none;color:var(--text-muted);overflow-wrap:anywhere}
.footer-links a:hover{color:var(--accent-dark)}
.footer-bottom{margin-top:40px;padding-top:24px;border-top:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;color:var(--text-muted);font-size:var(--small-size)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;gap:20px;flex-wrap:wrap}
.footer-legal a{min-height:24px;display:inline-flex;align-items:center}
.reveal{transition:opacity .35s var(--ease),transform .35s var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{display:grid;position:static;min-width:0;max-width:100%;min-height:120px;overflow:hidden;margin-top:24px;margin-bottom:32px;gap:16px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:32px}
.decor-section,.stripe-halo{overflow-x:clip;max-width:100%}
@media(min-width:1181px) and (max-width:1360px){
  .topbar{column-gap:16px;padding-inline:24px;grid-template-columns:auto minmax(0,1fr) auto}
  .tabs{justify-self:center}
  .tabs a{padding-inline:10px}
  .lang{padding-inline:8px}
}
@media(max-width:1180px) and (min-width:769px){
  .topbar{grid-template-columns:1fr auto;row-gap:12px;padding-bottom:12px}
  .tabs{grid-column:1 / -1;grid-row:2;justify-self:center;max-width:100%;overflow-x:auto}
  .top-actions{grid-column:2;grid-row:1}
}
@media(max-width:900px){
  .grid-3{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--header-height:72px;--anchor-offset:88px;--toc-offset:152px;--h1-size:38px;--section-space:56px}
  .topbar{display:flex;flex-wrap:nowrap;gap:12px;min-height:72px;padding:12px 16px;z-index:63;background:var(--bg)}
  .topbar>.tabs{display:none}
  .top-actions{margin-left:auto;gap:6px}
  .menu-toggle{display:inline-flex}
  .lang-text{display:none}
  .lang{padding:0 8px}
  .login{padding-inline:16px}
  .mobile-drawer{position:fixed;top:var(--header-height);left:0;right:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));z-index:62;padding:16px var(--gutter) 40px;background:var(--bg-panel);overflow-y:auto;overscroll-behavior:contain;border-top:1px solid var(--border)}
  .mobile-drawer.is-open{display:block}
  .mobile-drawer a{display:flex;width:100%;align-items:center;min-height:48px;padding:12px 16px;text-decoration:none;border-radius:var(--radius-md)}
  .mobile-drawer a.is-active{background:var(--bg-panel-2);color:var(--accent-dark);font-weight:var(--bold-weight)}
  .drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
  .nav-veil{position:fixed;inset:var(--header-height) 0 0;z-index:61;background:var(--veil);border:0;width:100%}
  .nav-veil.is-open{display:block}
  .grid-2,.grid-3{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:640px){
  :root{--gutter:16px}
  .no-break{white-space:normal}
  .tilt,.micro-tilt{transform:none}
  .decor-section,.stripe-halo{max-width:100%;overflow-x:clip}
  .brand{gap:7px}
  .brand img{width:30px;height:30px}
  .brand-word{font-size:19px}
  .topbar{gap:6px}
  .top-actions{gap:4px}
  .lang{min-width:36px;padding-inline:5px}
  .login{padding-inline:12px;font-size:14px}
  .btn{min-height:48px;font-size:17px;padding-inline:22px}
  .btn-primary{padding:0 18px 0 24px}
  .panel{padding:24px}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:359px){
  .brand-word{font-size:17px}
  .brand img{width:26px;height:26px}
  .brand{gap:5px}
  .lang .caret{display:none}
  .login{padding-inline:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}