:root{
  color-scheme:light;
  --bg:#F8F8FB;
  --panel:#FFFFFF;
  --panel-2:#EEEFF6;
  --border:#E2E4EE;
  --accent:#5468FF;
  --accent-dark:#3A45D6;
  --text:#191B2E;
  --muted:#5F6378;
  --success:#1DB57E;
  --warn:#E8A400;
  --error:#E5484D;
  --coral:#FF5A6E;
  --sun:#FFC93C;
  --mint:#1DC28A;
  --pink:#F25BB8;
  --accent-soft:#E8EBFF;
  --accent-line:#CDD3FF;
  --accent-wash:rgba(84,104,255,.06);
  --success-soft:rgba(29,181,126,.13);
  --mint-soft:rgba(29,194,138,.20);
  --sheen:rgba(84,104,255,.035);
  --white-hl:rgba(255,255,255,.85);
  --atmo-a:rgba(84,104,255,.07);
  --atmo-b:rgba(242,91,184,.045);
  --atmo-0:rgba(248,248,251,0);
  --veil:rgba(25,27,46,.22);
  --shadow-soft:0 2px 8px -2px rgba(84,104,255,.10);
  --shadow-panel:0 34px 72px -24px rgba(84,104,255,.20),0 10px 26px -10px rgba(84,104,255,.10);
  --shadow-tray:0 44px 96px -36px rgba(84,104,255,.16);
  --shadow-float:0 18px 40px -14px rgba(84,104,255,.26),0 3px 8px -2px rgba(84,104,255,.08);
  --shadow-pop:0 22px 46px -16px rgba(84,104,255,.32),0 6px 18px -8px rgba(242,91,184,.24);
  --shadow-btn:0 12px 26px -10px rgba(84,104,255,.55);
  --shadow-ink:0 1px 3px rgba(25,27,46,.10);
  --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,'SFMono-Regular',Menlo,Consolas,monospace;
  --r-window:24px;
  --r-card:20px;
  --r-tray:40px;
  --r-md:16px;
  --r-sm:12px;
  --r-cell:8px;
  --r-row:10px;
  --r-pop:18px;
  --r-mobile-tray:32px;
  --r-pill:999px;
  --r-circle:50%;
  --r-line:2px;
  --r-group:4px;
  --gutter:48px;
  --wrap-max:1408px;
  --head-height:72px;
  --anchor-offset:88px;
  --toc-offset:156px;
  --cols:128px 118px minmax(0,1fr) 140px;
  --ease-ui:.2s ease;
  --ease-reveal:.45s ease;
}
*,*::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:16px;line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
a{color:inherit}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
ul{margin:0;padding:0;list-style:none}
p{margin:0 0 1em}
h1,h2,h3{font-family:var(--font-display);overflow-wrap:break-word;text-wrap:balance}
h1{margin:24px 0 0;font-size:clamp(52px,4.4vw,64px);font-weight:800;line-height:1.1;letter-spacing:-.02em}
h2{margin:0 0 24px;font-size:clamp(28px,3vw,40px);font-weight:800;line-height:1.2;letter-spacing:-.02em}
h3{margin:0 0 16px;font-size:24px;line-height:1.35}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-cell)}
[hidden]{display:none!important}
.wrap{width:min(var(--wrap-max),100%);margin-inline:auto;padding-inline:var(--gutter)}
.wrap>*{min-width:0}
.section{padding-top:64px;padding-bottom:64px}
.section-title{text-align:center}
.reading-wrap{max-width:880px;margin-inline:auto;min-width:0}
.prose{min-width:0;overflow-wrap:break-word;line-height:1.85}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose ul{list-style:disc;padding-left:24px;margin-bottom:24px}
.prose ol{padding-left:24px;margin-bottom:24px}
.prose a{color:var(--accent-dark);text-underline-offset:4px}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere;background:var(--panel-2);border-radius:var(--r-group);padding:2px 5px}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:20px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-sm)}
pre code{padding:0;overflow-wrap:normal;white-space:pre;background:none}
.no-break{white-space:nowrap}
.kw{color:var(--accent)}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.vh{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip{position:absolute;left:16px;top:-48px;z-index:80;padding:8px 16px;background:var(--panel);border-radius:var(--r-pill);box-shadow:var(--shadow-float);text-decoration:none}
.skip:focus{top:12px}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.ln{fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.f-w{fill:var(--panel)}
.f-r{fill:var(--error)}
.f-b{fill:var(--accent-dark)}
.f-g{fill:var(--success)}
.f-ring{fill:none;stroke:var(--border);stroke-width:1;vector-effect:non-scaling-stroke}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;height:56px;padding:0 28px;border:0;border-radius:var(--r-pill);font-size:17px;font-weight:600;text-decoration:none;flex-shrink:0;white-space:nowrap;transition:transform var(--ease-ui),box-shadow var(--ease-ui),background-color var(--ease-ui)}
.btn svg{width:18px;height:18px}
.btn-primary{background:linear-gradient(135deg,var(--accent),var(--accent-dark));color:var(--panel);box-shadow:var(--shadow-btn)}
.btn-primary:hover{transform:translateY(-1px)}
.btn-primary:active{transform:translateY(0);background:var(--accent-dark)}
.btn-ghost,.btn-secondary{background:var(--panel);color:var(--text);border:1.5px solid var(--border)}
.btn-ghost:hover,.btn-secondary:hover{border-color:var(--accent-line);background:var(--accent-soft)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--panel-2);color:var(--muted);box-shadow:none;transform:none}
.btn-small{height:44px;padding-inline:20px;font-size:15px}
.card,.panel{min-width:0;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);padding:28px;box-shadow:var(--shadow-soft)}
.panel{border-radius:var(--r-window);box-shadow:var(--shadow-panel)}
.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.card-grid>*{min-width:0}
.decorative-section{position:relative;overflow-x:clip;max-width:100%}
.reveal{transition:opacity var(--ease-reveal),transform var(--ease-reveal)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{display:block;position:relative;min-width:0;max-width:100%;overflow:hidden;margin-top:32px;margin-bottom:32px}
#server-status+*{margin-top:32px}
#server-status>*{min-width:0;max-width:100%}
.site-head,#site-header{position:relative;z-index:60;min-height:var(--head-height)}
.head-in{position:relative;display:flex;align-items:center;height:var(--head-height);gap:24px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex:none}
.brand-mark{width:34px;height:34px;flex:none;display:block}
.brand-en{font-family:var(--font-display);font-weight:800;font-size:20px;letter-spacing:-.02em;line-height:1}
.brand-zh{font-size:14px;font-weight:500;color:var(--muted);line-height:1;padding-left:10px;border-left:1px solid var(--border)}
.nav{display:flex;align-items:center;gap:4px;margin-left:24px}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px}
.nav> a,.nav li>a,.nav-more>button{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:38px;padding:0 16px;border-radius:var(--r-pill);font-size:15px;font-weight:500;color:var(--text);text-decoration:none;background:none;border:0;cursor:pointer;transition:background-color var(--ease-ui),color var(--ease-ui)}
.nav a:hover,.nav-more>button:hover{background:var(--panel-2)}
.nav a[aria-current="page"],.nav-more>button.is-current{background:var(--accent-soft);color:var(--accent-dark);font-weight:600}
.nav-more{position:relative}
.nav-more svg{width:14px;height:14px;color:var(--muted)}
.nav-menu{position:absolute;top:calc(100% + 10px);left:0;min-width:248px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-md);box-shadow:var(--shadow-float)}
.nav-menu-label{margin:4px 10px 6px;font-size:12px;font-weight:600;color:var(--muted)}
.nav .nav-menu a{display:block;height:auto;padding:10px 12px;border-radius:var(--r-sm);text-decoration:none}
.nav-menu b{display:block;font-size:14.5px;font-weight:600;color:var(--text)}
.nav-menu span{display:block;font-size:12.5px;color:var(--muted);line-height:1.5}
.head-end{margin-left:auto;display:flex;align-items:center;gap:12px}
.lang-wrap{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;width:auto;height:38px;padding:0 12px;background:none;border:0;border-radius:var(--r-pill);font-size:14px;color:var(--muted);cursor:pointer}
.lang span{white-space:nowrap}
.lang:hover{background:var(--panel-2)}
.lang svg{width:16px;height:16px}
.lang-menu{position:absolute;right:0;top:calc(100% + 10px);min-width:180px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-md);padding:8px;box-shadow:var(--shadow-float)}
.lang-menu a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-sm)}
.lang-menu a:hover,.lang-menu a[aria-current="true"]{background:var(--accent-soft);color:var(--accent-dark)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:40px;padding:0 22px;border:1.5px solid var(--accent);border-radius:var(--r-pill);background:var(--panel);color:var(--accent-dark);font-size:15px;font-weight:600;text-decoration:none;white-space:nowrap;flex:none;transition:background-color var(--ease-ui)}
.btn-login:hover{background:var(--accent-soft)}
.burger{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:8px;border:1px solid var(--border);border-radius:var(--r-pill);background:var(--panel)}
.burger svg{width:20px;height:20px}
.mobile-drawer{display:none}
.nav-veil{position:fixed;inset:var(--head-height) 0 0;z-index:-1;border:0;background:var(--veil)}
html.nav-open{overflow:hidden}
.site-footer,#site-footer{background:var(--panel-2);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px;padding-top:48px;padding-bottom:32px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:30em;color:var(--muted);font-size:14px}
.footer-title{font-size:15px;font-weight:700;margin:0 0 14px}
.footer-links{display:flex;flex-wrap:wrap;gap:6px 16px}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;font-size:14px;text-decoration:none;color:var(--muted)}
.footer-links a:hover{color:var(--accent-dark);text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;border-top:1px solid var(--border);padding-top:20px;padding-bottom:24px;font-size:13px;color:var(--muted)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px;text-underline-offset:4px}
@media(max-width:900px){
  .nav{margin-left:8px}
  .nav li>a,.nav-more>button{padding-inline:12px}
  .brand-zh{display:none}
  .head-in{gap:12px}
}
@media(max-width:768px){
  :root{--gutter:20px;--head-height:64px;--anchor-offset:80px;--toc-offset:148px}
  h1{font-size:clamp(28px,9vw,40px)}
  h2{font-size:30px}
  .head-in{gap:12px}
  .nav{display:none}
  .head-end{margin-left:auto;gap:6px}
  .lang span{display:none}
  .lang{padding-inline:8px;min-height:44px}
  .btn-login{padding-inline:16px}
  .burger{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block;position:absolute;top:var(--head-height);left:var(--gutter);right:var(--gutter);z-index:2;max-height:calc(100dvh - var(--head-height) - 16px);overflow-y:auto;overscroll-behavior:contain;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);padding:12px;box-shadow:var(--shadow-float)}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 14px;border-radius:var(--r-sm);text-decoration:none}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current]{background:var(--accent-soft);color:var(--accent-dark)}
  .drawer-label{font-size:12px;font-weight:600;color:var(--muted);padding:12px 14px 4px;margin:0}
  .btn{height:52px;font-size:16px;padding-inline:24px}
  .btn-small{height:44px;font-size:14px;padding-inline:18px}
  .section{padding-top:48px;padding-bottom:48px}
  .card-grid{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:24px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,.decorative-tilt{transform:none}
  .decorative-section{max-width:100%;overflow-x:clip}
  .card,.panel{padding:22px}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .brand-en{font-size:18px}
  .brand-mark{width:28px;height:28px}
  .brand{gap:7px}
  .head-in{gap:6px}
  .head-end{gap:2px}
  .btn-login{padding-inline:12px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}