:root{
  --bg:#E9EDF9;
  --bg-top:#F3F5FD;
  --bg-bottom:#E4E9F7;
  --halo:#DCE6FF;
  --halo-fade:rgba(220,230,255,0);
  --panel:#F7F8FE;
  --panel-2:#DCE2F4;
  --border:#CDD4EC;
  --accent:#1A2152;
  --accent-dark:#0E1334;
  --deep:#2A3478;
  --peri:#6C7FE0;
  --peri-hi:#C9D3FF;
  --text:#0F1226;
  --muted:#565C7A;
  --success:#1E8A5A;
  --success-ring:rgba(30,138,90,.16);
  --warn:#B7791F;
  --error:#C2413A;
  --white:#FFFFFF;
  --clear:transparent;
  --ink-06:rgba(26,33,82,.06);
  --ink-10:rgba(26,33,82,.10);
  --ink-14:rgba(26,33,82,.14);
  --ink-22:rgba(26,33,82,.22);
  --ink-30:rgba(26,33,82,.30);
  --hi-edge:rgba(255,255,255,.92);
  --btn-sheen:rgba(255,255,255,.14);
  --on-deep:rgba(255,255,255,.94);
  --on-deep-muted:rgba(201,211,255,.76);
  --on-deep-sep:rgba(201,211,255,.42);
  --on-deep-faint:rgba(201,211,255,.16);
  --on-deep-hair:rgba(201,211,255,.08);
  --deep-veil:rgba(14,19,52,.58);
  --tile:rgba(255,255,255,.06);
  --star:rgba(255,255,255,.92);
  --star-faint:rgba(255,255,255,.55);
  --flag-red:#D3302F;
  --flag-blue:#27408B;
  --flag-black:#17171D;
  --flag-gold:#F0B92B;
  --flag-white:#FFFFFF;
  --r-card:10px;
  --r-tile:8px;
  --r-query-small:20px;
  --r-pill:999px;
  --r-circle:50%;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Malgun Gothic","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Malgun Gothic","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",Menlo,Consolas,"Liberation Mono",monospace;
  --weight-regular:400;
  --weight-medium:500;
  --weight-semibold:600;
  --weight-bold:700;
  --size-body:16px;
  --size-small:13px;
  --size-h1:64px;
  --size-h2:32px;
  --size-h3:20px;
  --gutter:40px;
  --content-width:1440px;
  --reading-width:820px;
  --header-height:72px;
  --anchor-space:96px;
  --toc-space:148px;
  --ease:ease;
  --speed-fast:.15s;
  --speed-reveal:.35s;
  --shadow-panel:0 28px 64px -22px var(--ink-10),0 8px 20px -12px var(--ink-06),inset 0 1px 0 var(--hi-edge);
  --shadow-float:0 16px 32px -12px var(--ink-22),0 2px 6px var(--ink-06),inset 0 1px 0 var(--hi-edge);
  --shadow-deep:0 36px 80px -32px var(--ink-30),0 14px 30px -18px var(--ink-22);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-space);scroll-behavior:smooth}
body{margin:0;min-height:100vh;font-family:var(--font-body);font-size:var(--size-body);line-height:1.5;color:var(--text);background:linear-gradient(180deg,var(--bg-top) 0%,var(--bg) 48%,var(--bg-bottom) 100%);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration-thickness:1px}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a,input,select,textarea,summary{-webkit-tap-highlight-color:var(--ink-10)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
[hidden]{display:none!important}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
h1,h2,h3,h4,p{overflow-wrap:break-word}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-bold);text-wrap:balance}
h1{font-size:var(--size-h1);line-height:1.12;letter-spacing:-.02em}
h2{font-size:var(--size-h2);line-height:1.25;letter-spacing:-.015em;margin:0 0 24px}
h3{font-size:var(--size-h3);line-height:1.35;margin:0 0 12px}
p{margin:0 0 16px}
ul,ol{padding-inline-start:24px}
code{font-family:var(--font-mono);overflow-wrap:anywhere;background:var(--panel-2);border-radius:var(--r-tile);padding:2px 5px}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-card)}
pre code{white-space:pre;overflow-wrap:normal;padding:0}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
.no-break{white-space:nowrap}
.wrap{width:min(100%,var(--content-width));margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{max-width:var(--reading-width);margin-inline:auto}
.section{padding-top:72px;padding-bottom:72px}
.section-head{max-width:var(--reading-width);margin-bottom:32px}
.section-head p,.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.panel,.card{min-width:0;padding:24px;border:1px solid var(--border);border-radius:var(--r-card);background:var(--panel);box-shadow:var(--shadow-panel)}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.grid>*{min-width:0}
.stack{display:grid;gap:20px;min-width:0}
.action-row{display:flex;align-items:center;flex-wrap:wrap;gap:12px}
.prose{min-width:0;line-height:1.85}
.prose h2{margin-top:48px}
.prose h3{margin-top:28px}
.prose a{text-decoration:underline;text-underline-offset:3px}
.prose li+li{margin-top:8px}
.prose blockquote{margin-inline:0}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.stage{position:relative;overflow-x:clip;max-width:100%}
.stage::before{content:"";position:absolute;inset:-200px -14% 34% 50%;background:radial-gradient(closest-side,var(--halo) 0%,var(--halo) 38%,var(--halo-fade) 100%);pointer-events:none;z-index:0}
.site-head{position:relative;z-index:40}
.head-row{position:relative;display:flex;align-items:center;gap:44px;height:var(--header-height)}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;color:var(--text)}
.brand-mark{width:30px;height:30px;flex:none;display:block}
.brand-en{font-family:var(--font-display);font-weight:var(--weight-bold);font-size:18px;letter-spacing:-.015em;color:var(--text);white-space:nowrap}
.brand-zh{font-weight:var(--weight-medium);font-size:15px;color:var(--muted);white-space:nowrap}
.nav{flex:1;min-width:0}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:28px}
.nav a{display:inline-flex;align-items:center;min-height:24px;font-size:15px;font-weight:var(--weight-medium);color:var(--muted);white-space:nowrap;transition:color var(--speed-fast) var(--ease)}
.nav a:hover{color:var(--text)}
.nav a[aria-current="page"]{color:var(--text);font-weight:var(--weight-semibold)}
.head-tools{display:flex;align-items:center;gap:10px;flex-shrink:0}
.language-control,.nav-more{position:relative}
.nav-more button{cursor:pointer}
.nav-more-panel{position:absolute;top:calc(100% + 8px);right:0;z-index:80;min-width:200px;padding:8px;border:1px solid var(--border);border-radius:var(--r-card);background:var(--panel);box-shadow:var(--shadow-float)}
.nav-more-panel a{display:flex;min-height:44px;padding:8px 14px}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:38px;padding:0 10px;border:0;background:var(--clear);cursor:pointer;font:inherit;font-size:14px;color:var(--muted);white-space:nowrap;min-width:44px;width:auto}
.lang:hover{color:var(--text)}
.lang-panel{position:absolute;right:0;top:calc(100% + 8px);z-index:80;min-width:180px;padding:8px;border:1px solid var(--border);border-radius:var(--r-card);background:var(--panel);box-shadow:var(--shadow-float)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 14px;border-radius:var(--r-tile);color:var(--text)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--panel-2)}
.pill{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:38px;padding:0 18px;border:0;border-radius:var(--r-pill);font-size:14px;font-weight:var(--weight-semibold);white-space:nowrap;transition:background-color var(--speed-fast) var(--ease),color var(--speed-fast) var(--ease)}
.pill--soft{background:var(--panel-2);color:var(--text);box-shadow:inset 0 1px 0 var(--hi-edge)}
.pill--soft:hover{background:var(--border)}
.pill--ink{background:var(--accent);color:var(--white);box-shadow:inset 0 1px 0 var(--btn-sheen),0 10px 22px -10px var(--ink-30)}
.pill--ink:hover{background:var(--accent-dark)}
.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(--r-tile);background:var(--panel);color:var(--accent)}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{position:fixed;top:var(--header-height);right:0;left:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));padding:16px var(--gutter) 32px;background:var(--panel);z-index:60;overflow-y:auto;overscroll-behavior:contain}
.mobile-drawer ul{list-style:none;margin:0;padding:0}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;color:var(--text);border-bottom:1px solid var(--border)}
.mobile-drawer a[aria-current]{font-weight:var(--weight-semibold);background:var(--panel-2)}
.drawer-languages{border-top:1px solid var(--border);margin-top:20px;padding-top:12px}
.menu-veil{position:fixed;inset:var(--header-height) 0 0;background:var(--deep-veil);z-index:50;border:0}
html.nav-open{overflow:hidden}
.btn,.btn-primary,.btn-secondary{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:48px;padding:0 22px;border:1px solid var(--clear);border-radius:var(--r-pill);font-size:15px;font-weight:var(--weight-semibold);white-space:nowrap;flex-shrink:0;transition:background-color var(--speed-fast) var(--ease),border-color var(--speed-fast) var(--ease)}
.btn svg{width:15px;height:15px;flex:none;display:block}
.btn--line,.btn-secondary{border-color:var(--ink-22);color:var(--accent);background:var(--clear)}
.btn--line:hover,.btn-secondary:hover{border-color:var(--accent);background:var(--panel-2)}
.btn--ink,.btn-primary{background:var(--accent);color:var(--white);box-shadow:inset 0 1px 0 var(--btn-sheen),0 12px 24px -12px var(--ink-30)}
.btn--ink:hover,.btn-primary:hover{background:var(--accent-dark)}
.btn:active,.pill:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;cursor:not-allowed;box-shadow:none}
.site-footer{position:relative;margin-top:48px;border-top:1px solid var(--border);background:var(--panel-2);padding-top:48px;padding-bottom:24px}
.footer-grid{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(0,1fr) minmax(0,1fr);gap:40px}
.footer-grid>*{min-width:0}
.footer-intro{margin-top:18px;max-width:400px;color:var(--muted)}
.footer-title{font-size:15px;font-weight:var(--weight-semibold);margin-bottom:14px}
.footer-links{display:flex;flex-wrap:wrap;gap:8px 20px;list-style:none;padding:0;margin:0}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;font-size:14px;color:var(--muted)}
.footer-links a:hover{color:var(--accent);text-decoration:underline}
.footer-bottom{margin-top:32px;padding-top:20px;border-top:1px solid var(--border);display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;color:var(--muted);font-size:13px}
.footer-bottom p{margin:0}
.reveal{transition:opacity var(--speed-reveal) var(--ease),transform var(--speed-reveal) var(--ease)}
.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-block:24px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:24px}
@media(min-width:1241px){.mobile-drawer,.menu-veil{display:none!important}}
@media(max-width:1240px){
  .head-row{gap:20px}
  .brand{margin-right:auto}
  .nav{display:none}
  .head-tools{margin-left:auto}
  .menu-toggle{display:inline-flex}
}
@media(max-width:768px){
  :root{--gutter:20px;--size-h1:40px;--size-h2:28px}
  .head-row{flex-wrap:nowrap;gap:10px}
  .head-tools{gap:6px;margin-left:auto}
  .lang{padding:0 6px;font-size:13px}
  .pill{padding:0 14px;height:34px;font-size:13px}
  .head-signup{display:none}
  .brand-zh{display:none}
  .section{padding-top:48px;padding-bottom:48px}
  .grid,.footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-grid{gap:28px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .stage::before{max-width:100%;inset:-120px 0 40% 35%}
}
@media(max-width:420px){
  :root{--gutter:16px;--size-h1:34px}
  .brand{gap:6px}
  .brand-en{font-size:14px}
  .brand-mark{width:26px;height:26px}
  .head-tools{gap:2px}
  .head-tools .pill{padding-inline:10px}
  .lang{font-size:12px;padding-inline:4px;gap:2px}
  .panel,.card{padding:20px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}