:root{
  --bg:#F6F7F8;
  --bg-panel:#FFFFFF;
  --bg-panel2:#EEF0F3;
  --border:#DFE2E7;
  --accent:#2A5BC8;
  --accent-dark:#1D43A0;
  --text:#16181C;
  --text-muted:#5E6470;
  --success:#1F9D6B;
  --warn:#E7843B;
  --error:#D64545;
  --on-accent:#FFFFFF;
  --tl-close:#FF5F57;
  --tl-min:#FEBC2E;
  --tl-zoom:#28C840;
  --flag-red:#D6283B;
  --flag-white:#FFFFFF;
  --flag-navy:#1B2D6B;
  --flag-blue:#253E86;
  --font-display:"Inter","Noto Sans SC",-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans","Microsoft YaHei","Malgun Gothic",sans-serif;
  --font-body:"Inter","Noto Sans SC",-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans","Microsoft YaHei","Malgun Gothic",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SF Mono",Menlo,Consolas,monospace;
  --r-btn:8px;
  --r-win:14px;
  --r-card:24px;
  --r-tag:5px;
  --r-item:8px;
  --r-chip:14px;
  --r-pill:999px;
  --r-small:6px;
  --r-region:7px;
  --r-space:10px;
  --r-now:12px;
  --r-icon:9px;
  --r-round:50%;
  --gutter:32px;
  --page-width:1240px;
  --reading-width:840px;
  --header-height:64px;
  --anchor-offset:80px;
  --toc-offset:88px;
  --toc-landing:160px;
  --size-body:17px;
  --size-display:64px;
  --size-h2:36px;
  --size-h3:24px;
  --size-small:14px;
  --weight-display:800;
  --weight-bold:700;
  --weight-medium:600;
  --atmo-top:color-mix(in srgb,var(--accent) 7%,var(--bg));
  --atmo-mid:color-mix(in srgb,var(--accent) 3%,var(--bg));
  --glow-warm:color-mix(in srgb,var(--warn) 8%,transparent);
  --tint-accent-04:color-mix(in srgb,var(--accent) 4%,var(--bg-panel));
  --tint-accent-10:color-mix(in srgb,var(--accent) 10%,var(--bg-panel));
  --tint-accent-16:color-mix(in srgb,var(--accent) 16%,var(--bg-panel));
  --tint-accent-22:color-mix(in srgb,var(--accent) 22%,var(--bg-panel));
  --tint-warm:color-mix(in srgb,var(--warn) 12%,var(--bg-panel));
  --tint-warm-soft:color-mix(in srgb,var(--warn) 3%,var(--bg-panel));
  --shadow-accent-12:color-mix(in srgb,var(--accent) 12%,transparent);
  --shadow-accent-08:color-mix(in srgb,var(--accent) 8%,transparent);
  --shadow-accent-30:color-mix(in srgb,var(--accent) 30%,transparent);
  --shadow-ink-06:color-mix(in srgb,var(--text) 6%,transparent);
  --shadow-ink-16:color-mix(in srgb,var(--text) 16%,transparent);
  --hi-line:color-mix(in srgb,var(--bg-panel) 92%,transparent);
  --hi-button:color-mix(in srgb,var(--bg-panel) 24%,transparent);
  --line-soft:color-mix(in srgb,var(--border) 65%,var(--bg-panel));
  --sep:color-mix(in srgb,var(--text-muted) 45%,var(--bg));
  --text-soft:color-mix(in srgb,var(--text) 74%,var(--bg));
  --chrome-end:color-mix(in srgb,var(--bg-panel2) 45%,var(--bg-panel));
  --side-chrome-top:color-mix(in srgb,var(--bg-panel) 40%,var(--bg-panel2));
  --side-selected:color-mix(in srgb,var(--border) 78%,var(--bg-panel2));
  --flag-edge:color-mix(in srgb,var(--text) 14%,transparent);
  --primary-top:color-mix(in srgb,var(--accent) 90%,var(--bg-panel));
  --tag-shop-bg:color-mix(in srgb,var(--accent) 11%,var(--bg-panel));
  --tag-shop-fg:var(--accent);
  --tag-ads-bg:color-mix(in srgb,var(--warn) 15%,var(--bg-panel));
  --tag-ads-fg:color-mix(in srgb,var(--warn) 74%,var(--text));
  --tag-stream-bg:color-mix(in srgb,var(--success) 13%,var(--bg-panel));
  --tag-stream-fg:color-mix(in srgb,var(--success) 86%,var(--text));
  --tag-ai-bg:var(--bg-panel2);
  --tag-ai-fg:var(--text-muted);
  --shadow-window:0 1px 2px var(--shadow-ink-06),0 22px 60px -14px var(--shadow-accent-12),0 56px 120px -28px var(--shadow-accent-12);
  --shadow-chip:0 0 0 1px var(--border),inset 0 1px 0 var(--hi-line),0 2px 6px var(--shadow-ink-06),0 14px 34px -10px var(--shadow-accent-12);
  --shadow-panel:inset 0 1px 0 var(--hi-line),0 16px 48px -24px var(--shadow-accent-12);
  --ease-duration:.15s;
}
*,*::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(--size-body);line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
p{margin:0}
ul{margin:0;padding:0;list-style:none}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);text-wrap:balance}
h1{font-size:clamp(52px,5vw,var(--size-display));font-weight:var(--weight-display);line-height:1.12;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:var(--size-h2);font-weight:var(--weight-bold);line-height:1.25;letter-spacing:-.02em;margin:0 0 24px}
h3{font-size:var(--size-h3);font-weight:var(--weight-bold);line-height:1.35;margin:0 0 16px}
h4{margin:0 0 12px;font-weight:var(--weight-bold)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:4px}
[hidden]{display:none!important}
.wrap{width:100%;max-width:var(--page-width);margin:0 auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading-width);margin:0 auto;padding-inline:var(--gutter)}
.section{padding-top:64px;padding-bottom:64px}
.section-heading{max-width:760px;margin-bottom:32px}
.section-heading p{color:var(--text-muted)}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.panel,.card{background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-card);padding:32px;box-shadow:var(--shadow-panel);min-width:0}
.panel-muted{background:var(--bg-panel2)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.icon{width:24px;height:24px;flex:none}
.svg-defs{position:absolute;width:0;height:0;overflow:hidden}
.fw{fill:var(--flag-white)}
.fr{fill:var(--flag-red)}
.fn{fill:var(--flag-navy)}
.fb{fill:var(--flag-blue)}
.sw{stroke:var(--flag-white);fill:none}
.sr{stroke:var(--flag-red);fill:none}
.flag-edge{fill:none;stroke:var(--flag-edge);stroke-width:1}
.prose{min-width:0;overflow-wrap:break-word}
.prose p,.prose ul,.prose ol,.prose blockquote{margin-bottom:24px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose a{color:var(--accent-dark);text-decoration:underline;text-underline-offset:3px}
code{font-family:var(--font-mono);font-size:.88em;overflow-wrap:anywhere;word-break:break-word;background:var(--bg-panel2);border-radius:var(--r-small);padding:2px 5px}
pre{max-width:100%;overflow-x:auto;background:var(--bg-panel2);border:1px solid var(--border);border-radius:var(--r-win);padding:24px}
pre code{background:transparent;padding:0;white-space:pre;overflow-wrap:normal;word-break:normal}
.shell{position:relative;overflow:clip;max-width:100%;background:radial-gradient(52% 60% at 6% 100%,var(--glow-warm) 0%,transparent 72%),linear-gradient(180deg,var(--atmo-top) 0%,var(--atmo-mid) 38%,var(--bg) 72%)}
.decorated-section{position:relative;overflow-x:clip}
#server-status{position:relative;display:block;min-height:64px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:24px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:0 24px;border:0;border-radius:var(--r-btn);font-family:var(--font-body);font-size:16px;font-weight:650;line-height:1.3;flex-shrink:0;white-space:nowrap;transition:background var(--ease-duration) ease,box-shadow var(--ease-duration) ease}
.btn-ico{width:16px;height:16px;flex:none}
.btn-primary{background:linear-gradient(180deg,var(--primary-top),var(--accent));color:var(--on-accent);box-shadow:inset 0 1px 0 var(--hi-button),0 1px 2px var(--shadow-accent-30),0 10px 24px -8px var(--shadow-accent-30)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent-dark)}
.btn-ghost,.btn-secondary{background:var(--bg-panel);color:var(--text);box-shadow:0 0 0 1px var(--border),inset 0 1px 0 var(--hi-line),0 1px 2px var(--shadow-ink-06)}
.btn-ghost:hover,.btn-secondary:hover,.btn-ghost.is-hover{background:var(--bg-panel2)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn.is-disabled{background:var(--bg-panel2);color:var(--text-muted);box-shadow:inset 0 0 0 1px var(--border)}
.btn.is-focus{outline:2px solid var(--accent);outline-offset:4px}
.cta-row{margin-top:22px;display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.topbar,#site-header{position:relative;z-index:50}
.topbar-inner{height:var(--header-height);display:flex;align-items:center;gap:24px;position:relative}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;min-height:34px}
.brand-mark{width:30px;height:30px;flex:none;filter:drop-shadow(0 4px 10px var(--shadow-accent-30))}
.brand-en{font-family:var(--font-display);font-weight:var(--weight-display);font-size:18px;letter-spacing:-.02em;color:var(--text)}
.brand-zh{font-size:15px;font-weight:500;color:var(--text-muted)}
.nav{margin-left:auto}
.nav-list{display:flex;align-items:center;list-style:none;margin:0;padding:0}
.nav-list li{display:flex;align-items:center;font-size:14.5px;line-height:1}
.nav-list li+li::before{content:"·";margin:0 11px;color:var(--sep)}
.nav-list a{color:var(--text-muted);padding:6px 0;min-height:24px;display:inline-flex;align-items:center;transition:color var(--ease-duration) ease}
.nav-list a:hover{color:var(--text)}
.nav-list a[aria-current="page"]{color:var(--text);font-weight:var(--weight-medium)}
.nav-tail{display:flex;align-items:center;gap:10px;flex:none}
.language-control{position:relative}
.lang{appearance:none;border:0;background:transparent;cursor:pointer;font:inherit;font-size:14px;color:var(--text-muted);min-height:34px;padding:0 10px;border-radius:var(--r-btn);display:inline-flex;align-items:center;justify-content:center;gap:6px;width:auto;white-space:nowrap}
.lang:hover{background:var(--bg-panel2);color:var(--text)}
.lang-caret{font-size:11px}
.lang-menu{position:absolute;right:0;top:calc(100% + 8px);min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-win);box-shadow:var(--shadow-chip);z-index:4}
.lang-menu a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-btn)}
.lang-menu a:hover,.lang-menu a[aria-current]{background:var(--bg-panel2)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:34px;padding:0 16px;border-radius:var(--r-btn);background:var(--accent-dark);color:var(--on-accent);font-size:14px;font-weight:var(--weight-medium);box-shadow:inset 0 1px 0 var(--hi-button),0 1px 2px var(--shadow-ink-16);transition:filter var(--ease-duration) ease;white-space:nowrap;flex:none}
.btn-login:hover{filter:brightness(1.12)}
.nav-toggle{display:none;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--r-btn);background:var(--bg-panel);align-items:center;justify-content:center}
.nav-toggle svg{width:20px;height:20px}
.mobile-drawer{display:none}
html.nav-open{overflow:hidden}
.site-footer{background:var(--bg-panel2);border-top:1px solid var(--border);padding-top:48px;padding-bottom:32px;margin-top:64px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-brand p{color:var(--text-muted);max-width:380px;margin-top:16px;font-size:15px}
.footer-title{font-size:15px;font-weight:var(--weight-bold);margin-bottom:12px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;font-size:14px;color:var(--text-muted)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--text)}
.footer-languages,.footer-legal{display:flex;flex-wrap:wrap;gap:8px 24px}
.footer-bottom{margin-top:32px;border-top:1px solid var(--border);padding-top:24px;display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px}
.copyright{color:var(--text-muted);font-size:13px}
.reveal{transition:opacity .6s ease,transform .6s ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
@media(max-width:1180px){
  .nav-list li{font-size:13.5px}
  .nav-list li+li::before{margin:0 8px}
}
@media(max-width:1080px){
  .nav{display:none}
  .nav-tail{margin-left:auto}
  .nav-toggle{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block;position:absolute;left:var(--gutter);right:var(--gutter);top:var(--header-height);background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-win);padding:12px;box-shadow:var(--shadow-chip);max-height:calc(100dvh - var(--header-height) - 16px);overflow-y:auto;overscroll-behavior:contain;z-index:6}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 12px;border-radius:var(--r-btn);font-size:15px}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current="page"]{background:var(--bg-panel2)}
  .drawer-languages{border-top:1px solid var(--border);margin-top:8px;padding-top:8px}
}
@media(max-width:768px){
  :root{--header-height:56px;--gutter:24px;--anchor-offset:72px;--toc-offset:72px;--toc-landing:144px;--size-h2:28px;--size-h3:22px}
  h1{font-size:40px;line-height:1.12}
  .section{padding-top:48px;padding-bottom:48px}
  .topbar-inner{gap:12px}
  .nav-tail{gap:8px;margin-left:auto}
  .language-control{display:none}
  .footer-grid{grid-template-columns:1fr 1fr;gap:32px}
  .footer-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:16px}
  .no-break{white-space:normal}
  .tilt,.decorative-tilt{transform:none}
  .decorated-section>*{max-width:100%}
  .panel,.card{padding:24px}
  .footer-grid{grid-template-columns:1fr;gap:24px}
  .footer-brand{grid-column:auto}
  .brand-en{font-size:17px}
  .brand-mark{width:28px;height:28px}
  .btn{padding-inline:20px}
}
@media(max-width:360px){
  h1{font-size:34px}
  .topbar-inner{gap:8px}
  .brand{gap:6px}
  .btn-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,.reveal.shown{opacity:1;transform:none}
}