:root {
  --bg:#E6E9F5;
  --bg-panel:#F7F8FD;
  --bg-panel-2:#D9DEF0;
  --hero-top:#EEF0FA;
  --hero-bottom:#E1E5F3;
  --border:#C9CFE6;
  --line-soft:rgba(201,207,230,.75);
  --accent:#7A1C5E;
  --accent-2:#B8367F;
  --accent-dark:#5A1244;
  --periwinkle:#8E9AE0;
  --text:#161A2E;
  --text-muted:#565C78;
  --success:#1F8A5B;
  --warn:#B7791F;
  --error:#C2362F;
  --white:#FFFFFF;
  --clear:transparent;
  --accent-a05:rgba(122,28,94,.05);
  --accent-a10:rgba(122,28,94,.10);
  --accent-a12:rgba(122,28,94,.12);
  --accent-a18:rgba(122,28,94,.18);
  --accent-a40:rgba(122,28,94,.40);
  --peri-a06:rgba(142,154,224,.06);
  --success-a12:rgba(31,138,91,.12);
  --ink-a05:rgba(22,26,46,.05);
  --ink-a08:rgba(22,26,46,.08);
  --veil:rgba(22,26,46,.32);
  --white-a18:rgba(255,255,255,.18);
  --white-a35:rgba(255,255,255,.35);
  --white-a70:rgba(255,255,255,.70);
  --flag-red:#D3263A;
  --flag-blue:#24418F;
  --flag-green:#1E7A48;
  --flag-white:#FFFFFF;
  --flag-edge:rgba(22,26,46,.16);
  --font-display:'Inter','Noto Sans SC','PingFang SC','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Microsoft YaHei',system-ui,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --text-base:16px;
  --text-small:14px;
  --text-display:clamp(52px,4.72vw,68px);
  --text-h2:clamp(28px,3vw,40px);
  --text-h3:21px;
  --r-xs:5px;
  --r-sm:6px;
  --r:8px;
  --r-lg:20px;
  --r-pill:999px;
  --shadow-card:0 18px 36px -18px var(--accent-a18),0 2px 6px var(--ink-a05);
  --shadow-win:0 34px 56px -24px var(--accent-a18),0 10px 22px -14px var(--accent-a12),0 1px 2px var(--ink-a05);
  --shadow-plate:0 48px 84px -36px var(--accent-a12);
  --shadow-button:0 16px 30px -16px var(--accent-a40),inset 0 1px 0 var(--white-a18);
  --shadow-button-hover:0 20px 34px -16px var(--accent-a40),inset 0 1px 0 var(--white-a18);
  --gutter:32px;
  --wrap-max:1296px;
  --header-height:72px;
  --anchor-offset:88px;
  --toc-offset:88px;
  --toc-landing:160px;
  --speed-fast:.2s;
  --speed-reveal:.35s;
  --logo-white:brightness(0) invert(1);
}
*,*::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(--text-base);line-height:1.6;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
html.nav-open{overflow:hidden}
[hidden]{display:none!important}
img{max-width:100%;height:auto;display:block}
svg{vertical-align:middle;flex-shrink:0}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,a,summary{-webkit-tap-highlight-color:var(--accent-a10)}
button{color:inherit}
a{color:inherit;text-underline-offset:.22em}
a:hover{ text-decoration-thickness:2px}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
h1,h2,h3,h4{font-family:var(--font-display);line-height:1.2;overflow-wrap:break-word}
h1,.h1{font-size:var(--text-display);font-weight:900;letter-spacing:-.02em;line-height:1.1;margin:0 0 32px}
h2{font-size:var(--text-h2);font-weight:900;letter-spacing:-.02em;margin:0 0 24px;text-wrap:balance}
h3{font-size:var(--text-h3);font-weight:750;margin:0 0 12px}
p{margin:0 0 20px}
ul,ol{padding-left:1.4em}
li+li{margin-top:6px}
code{font-family:var(--font-mono);overflow-wrap:anywhere;font-size:.9em}
pre{max-width:100%;overflow-x:auto;background:var(--bg-panel-2);padding:20px;border-radius:var(--r);font-family:var(--font-mono)}
pre code{overflow-wrap:normal;white-space:pre}
blockquote{margin:0}
section[id],h2[id],h3[id]{scroll-margin-top:var(--anchor-offset)}
body:has(.toc-tabs) section[id]{scroll-margin-top:var(--toc-landing)}
.wrap{width:100%;max-width:var(--wrap-max);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:80px;padding-bottom:80px}
.section-head{max-width:760px;margin-bottom:40px}
.reading-wrap{max-width:880px}
.prose{line-height:1.9;overflow-wrap:break-word}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose p:last-child{margin-bottom:0}
.prose li{margin-bottom:8px}
.no-break{white-space:nowrap}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.svg-defs{position:absolute;width:0;height:0;overflow:hidden}
.grid-2,.grid-3,.grid-5{display:grid;gap:24px}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-5{grid-template-columns:repeat(5,minmax(0,1fr))}
:where(.grid-2,.grid-3,.grid-5,.hero-grid,.feature-layout,.feature-items,.footer-grid)>*{min-width:0}
.panel,.card{background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r);padding:28px;box-shadow:var(--shadow-card)}
.panel-inset{background:var(--bg-panel-2);border-radius:var(--r);padding:24px}
.card h3:last-child,.card p:last-child,.panel p:last-child{margin-bottom:0}
.badge,.tag{display:inline-flex;align-items:center;gap:6px;max-width:100%;min-height:24px;padding:2px 9px;border:1px solid var(--border);border-radius:var(--r-pill);background:var(--bg-panel);font-size:12px;font-weight:600;overflow-wrap:anywhere}
.tag{font-family:var(--font-mono);border-radius:var(--r-xs)}
.badge-success{background:var(--success-a12);color:var(--success)}
.fact-pills{display:flex;flex-wrap:wrap;gap:8px}
.fact-pill{padding:6px 10px;border-radius:var(--r-sm);background:var(--white);border:1px solid var(--border);font-size:13px}
[data-count]{display:inline-block;min-width:3ch;text-align:end;font-variant-numeric:tabular-nums;font-family:var(--font-mono)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:12px 26px;border:0;border-radius:var(--r);font-size:16px;font-weight:600;line-height:1.5;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--speed-fast) ease,box-shadow var(--speed-fast) ease,background var(--speed-fast) ease}
.btn svg{width:16px;height:16px}
.btn-primary{color:var(--white);background:linear-gradient(135deg,var(--accent) 0%,var(--accent) 50%,var(--accent-2) 122%);box-shadow:var(--shadow-button)}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);box-shadow:var(--shadow-button-hover)}
.btn-primary:active{transform:translateY(0);background:var(--accent-dark)}
.btn-ghost,.btn-secondary{color:var(--text);background:var(--white);border:1.5px solid var(--text)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--bg-panel)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;cursor:not-allowed;transform:none;box-shadow:none}
.btn-small{min-height:40px;padding:8px 16px;font-size:14px}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin:0 0 28px}
.shell{position:relative;background:linear-gradient(180deg,var(--hero-top) 0%,var(--hero-bottom) 100%);overflow-x:clip;max-width:100%}
.shell::before{content:"";position:absolute;inset:0;background:linear-gradient(118deg,var(--accent-a05) 0%,var(--clear) 46%,var(--peri-a06) 100%);pointer-events:none}
.site-head,#site-header{position:relative;z-index:50}
.site-head{border-bottom:1px solid var(--line-soft)}
.head-row{display:flex;align-items:center;min-height:var(--header-height);gap:24px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex:none}
.brand-mark{width:30px;height:30px;flex:none}
.brand-en{font-family:var(--font-display);font-weight:900;font-size:21px;letter-spacing:-.02em;line-height:1}
.brand-zh{font-size:14px;font-weight:500;color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border);line-height:1.2}
.tabs{flex:1;align-self:stretch;min-width:0}
.tabs ul{display:flex;align-items:center;height:100%;list-style:none;margin:0;padding:0;gap:4px}
.tabs li{height:100%;margin:0}
.tab{position:relative;display:flex;align-items:center;height:100%;min-height:44px;padding:0 10px;font-size:15px;font-weight:500;color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--speed-fast) ease}
.tab::after{content:"";position:absolute;left:10px;right:10px;bottom:-1px;height:2px;border-radius:var(--r-xs);background:var(--text);transform:scaleX(0);transform-origin:center;transition:transform .25s ease}
.tab:hover{color:var(--text)}
.tab:hover::after{transform:scaleX(.45)}
.tab.is-active{color:var(--text);font-weight:600}
.tab.is-active::after{transform:scaleX(1)}
.head-tools{display:flex;align-items:center;gap:16px;flex-shrink:0;margin-left:auto}
.lang-box{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;min-height:38px;width:auto;padding:0 6px;border:0;background:var(--clear);font-size:14px;color:var(--text-muted);text-decoration:none;white-space:nowrap}
.lang svg{width:16px;height:16px}
.lang-label{white-space:nowrap}
.lang:hover{color:var(--text)}
.lang-panel{position:absolute;right:0;top:calc(100% + 10px);min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r);box-shadow:var(--shadow-card);z-index:80}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-xs)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--bg-panel-2)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:6px 18px;border:1.5px solid var(--text);border-radius:var(--r);background:var(--white);color:var(--text);font-size:14px;font-weight:600;text-decoration:none;white-space:nowrap;transition:background var(--speed-fast) ease,color var(--speed-fast) ease}
.btn-login:hover{background:var(--text);color:var(--white)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:10px;border:1px solid var(--border);border-radius:var(--r);color:var(--text);background:var(--bg-panel)}
.menu-toggle svg{width:22px;height:22px}
.nav-drawer{display:none}
.nav-veil{display:none}
.drawer-languages{padding-top:16px;margin-top:12px;border-top:1px solid var(--border)}
.static-language{position:relative}
.static-language>summary{list-style:none;cursor:pointer}
.static-language>summary::-webkit-details-marker{display:none}
.site-footer{position:relative;background:var(--bg-panel-2);border-top:1px solid var(--border);padding-top:56px;padding-bottom:28px}
.footer-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:26em;margin-top:20px;color:var(--text-muted);font-size:14px}
.footer-title{font-size:15px;font-weight:750;margin:0 0 16px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 16px;list-style:none;margin:0;padding:0}
.footer-links li{margin:0}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;font-size:14px;text-decoration:none}
.footer-links a:hover{text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;padding-top:32px}
.footer-languages a{display:inline-flex;align-items:center;min-height:32px;font-size:14px}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px 24px;border-top:1px solid var(--border);margin-top:24px;padding-top:20px;font-size:13px;color:var(--text-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:8px 20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px}
.reveal{transition:opacity var(--speed-reveal) ease,transform var(--speed-reveal) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-width:0;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}
.decorated-section{position:relative;overflow-x:clip;max-width:100%}
@media (max-width:1250px) and (min-width:1101px){
  .head-row{gap:16px}
  .tab{padding-inline:7px;font-size:14px}
  .head-tools{gap:8px}
}
@media (max-width:1100px){
  .head-row{flex-wrap:nowrap;gap:16px;height:var(--header-height)}
  #site-header .tabs{display:none}
  .head-tools{margin-left:auto;gap:10px}
  .menu-toggle{display:inline-flex}
  .nav-drawer{position:fixed;top:var(--header-height);inset-inline:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;padding:20px var(--gutter) 40px;background:var(--bg-panel);z-index:60}
  .nav-drawer:not([hidden]){display:block}
  .nav-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-sm);text-decoration:none;color:var(--text)}
  .nav-drawer a.is-active,.nav-drawer a:hover{background:var(--bg-panel-2)}
  .nav-veil:not([hidden]){display:block;position:fixed;inset:var(--header-height) 0 0;background:var(--veil);z-index:55;border:0}
  .site-head{z-index:70;background:var(--hero-top)}
  .static-head .head-row{flex-wrap:wrap;height:auto;padding-top:14px;gap:12px 16px}
  .static-head .tabs{order:3;flex:0 0 100%;height:48px;overflow-x:auto}
  .static-head .tabs ul{height:48px}
  .footer-grid{gap:32px}
}
@media (max-width:768px){
  :root{--gutter:20px;--text-display:40px;--text-h2:30px}
  h1,.h1{margin-bottom:24px}
  .sec{padding-top:48px;padding-bottom:48px}
  .grid-3{grid-template-columns:1fr}
  .grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
  .panel,.card{padding:24px}
}
@media (max-width:640px){
  .no-break{white-space:normal}
  .tilt,.tilt-card{transform:none}
  .decorated-section{max-width:100%}
  .grid-2{grid-template-columns:1fr}
  .head-row{gap:8px}
  .head-tools{gap:6px;margin-left:auto}
  .lang-label{display:none}
  .brand-en{font-size:19px}
  .brand-mark{width:26px;height:26px}
  .brand{gap:7px}
  .btn-login{padding-inline:12px}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
}
@media (max-width:360px){
  :root{--gutter:16px}
  .brand-en{font-size:17px}
  .head-tools{gap:4px}
  .btn-login{padding-inline:10px}
  .brand-mark{width:24px;height:24px}
  .btn{padding-inline:20px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}