:root{
  --bg:#EEEEFB;--panel:#F8F8FF;--groove:#E3E3F6;--border:#D6D6EE;--white:#FFFFFF;
  --accent:#6A3DF2;--accent-dark:#4B22C9;--magenta:#D84FC4;--coral:#FF7452;
  --text:#17152E;--muted:#5C5A78;--success:#1F9D6B;--warn:#D98A12;--error:#D63A4A;
  --hero-top:#F6F6FE;--hero-bottom:#E9E9F8;--lavender:#ECE7FF;--transparent:transparent;
  --accent-rgb:106 61 242;--magenta-rgb:216 79 196;--coral-rgb:255 116 82;--white-rgb:255 255 255;--text-rgb:23 21 46;--success-rgb:31 157 107;
  --flag-red:#E0283C;--flag-white:#FFFFFF;--flag-blue:#2B3F8F;--flag-navy:#1F2F6E;--flag-black:#1C1B22;--flag-gold:#F2C230;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --r-window:28px;--r-inner:22px;--r-float:18px;--r-card:16px;--r-row:12px;--r-chip:6px;--r-pill:999px;
  --r-brand:10px;--r-flag:3px;--r-bubble:14px;--r-tail:5px;--r-bar:8px;--r-bar-top:7px;--r-refund:9px;--r-round:50%;
  --shadow-window:0 60px 120px -40px rgb(var(--accent-rgb) / .12),0 24px 56px -24px rgb(var(--accent-rgb) / .12);
  --shadow-float:0 22px 44px -16px rgb(var(--accent-rgb) / .14),0 6px 14px -6px rgb(var(--accent-rgb) / .12);
  --shell:1280px;--gutter:80px;--header-height:64px;--anchor-offset:88px;--toc-offset:88px;--section-anchor:164px;
  --text-xs:12px;--text-sm:14px;--text-body:16px;--text-lead:20px;--text-h3:26px;--text-h2:40px;--text-h1:64px;
  --weight-body:400;--weight-medium:550;--weight-bold:700;--weight-display:800;
  --ease:200ms ease;--reveal-time:550ms;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;color-scheme:light;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-body);line-height:1.6;-webkit-font-smoothing:antialiased}
html.nav-open{overflow:hidden}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a,input,summary,select,textarea{-webkit-tap-highlight-color:rgb(var(--accent-rgb) / .12)}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
button{border:0}
img,svg,video{max-width:100%;vertical-align:middle}
img{height:auto}
svg{flex-shrink:0}
p{margin:0 0 1.2em}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--text-h1);font-weight:var(--weight-display);line-height:1.1;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:var(--text-h2);font-weight:var(--weight-display);line-height:1.2;letter-spacing:-.02em;margin:0 0 24px}
h3{font-size:var(--text-h3);line-height:1.3;margin:0 0 16px}
h4{font-size:var(--text-lead);margin:0 0 12px}
ul,ol{padding-left:1.4em}
li+li{margin-top:4px}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
code{font-family:var(--font-mono);font-size:.88em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;border-radius:var(--r-card);background:var(--groove);color:var(--text)}
pre code{overflow-wrap:normal;white-space:pre}
[hidden]{display:none!important}
.no-break{white-space:nowrap}
.shell,.wrap{width:100%;max-width:calc(var(--shell) + var(--gutter) * 2);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:80px;padding-bottom:80px}
.section--compact{padding-top:40px;padding-bottom:40px}
.section-head{max-width:760px;margin-bottom:32px}
.section-head p,.muted{color:var(--muted)}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid>*{min-width:0}
:where(main,article,section,aside,nav,header,footer,div){min-width:0}
.surface{background:var(--white);border:1px solid var(--border);border-radius:var(--r-window);padding:28px;box-shadow:var(--shadow-float),inset 0 1px 0 var(--white)}
.panel{background:var(--panel);border:1px solid var(--border);border-radius:var(--r-inner);padding:24px}
.decoration-zone{position:relative;overflow-x:clip;max-width:100%}
.prose{max-width:840px;overflow-wrap:break-word}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose a:not(.btn){color:var(--accent-dark);text-decoration:underline;text-underline-offset:3px}
.prose li{margin-bottom:10px}
.prose blockquote{margin-inline:0}
.reading-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(200px,280px);gap:40px;align-items:start}
.help-section{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,2fr);gap:40px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.skip-link{position:absolute;z-index:100;left:var(--gutter);top:8px;transform:translateY(-160%);background:var(--white);padding:10px 20px;border-radius:var(--r-pill)}
.skip-link:focus{transform:none}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.ico-s{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.icon{width:20px;height:20px;flex:none}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:48px;padding:0 26px;border:0;border-radius:var(--r-pill);font-size:var(--text-body);font-weight:var(--weight-bold);letter-spacing:-.005em;white-space:nowrap;flex-shrink:0;transition:background-color var(--ease),box-shadow var(--ease),transform var(--ease)}
.btn--primary,.btn-primary{background:var(--accent);color:var(--white);box-shadow:inset 0 1px 0 rgb(var(--white-rgb) / .28),0 12px 26px -12px rgb(var(--accent-rgb) / .7)}
.btn--primary:hover,.btn-primary:hover{background:var(--accent-dark)}
.btn--primary:active,.btn-primary:active{transform:translateY(1px);box-shadow:inset 0 1px 0 rgb(var(--white-rgb) / .28)}
.btn--ghost,.btn-secondary{background:var(--groove);color:var(--text);box-shadow:inset 0 0 0 1px rgb(var(--accent-rgb) / .06)}
.btn--ghost:hover,.btn-secondary:hover{background:var(--border)}
.btn--small{height:38px;padding-inline:18px;font-size:var(--text-sm)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;cursor:not-allowed;pointer-events:none}
.cta-row{display:flex;align-items:center;flex-wrap:wrap;gap:12px;margin-top:24px}
.reveal{transition:opacity var(--reveal-time) ease,transform var(--reveal-time) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:static;display:block;min-width:0;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}
.topbar{position:relative;z-index:40;background:rgb(var(--white-rgb) / .72);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);border-bottom:1px solid rgb(var(--text-rgb) / .06)}
.topbar__row{position:relative;display:flex;align-items:center;gap:32px;height:var(--header-height)}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none;min-height:38px}
.brand__mark{width:32px;height:32px;border-radius:var(--r-brand);flex:none}
.brand__name{font-family:var(--font-display);font-weight:var(--weight-display);font-size:19px;letter-spacing:-.02em}
.brand__zh{color:var(--muted);font-weight:var(--weight-medium)}
.mainnav{display:flex;align-items:center;gap:2px;margin-right:auto}
.mainnav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.mainnav li{margin:0}
.mainnav a{display:inline-flex;align-items:center;min-height:38px;padding:7px 13px;border-radius:var(--r-pill);font-size:14.5px;font-weight:500;color:var(--muted);white-space:nowrap;transition:color var(--ease),background-color var(--ease)}
.mainnav a:hover{color:var(--text);background:rgb(var(--accent-rgb) / .06)}
.mainnav a[aria-current="page"]{color:var(--accent-dark);background:rgb(var(--accent-rgb) / .11);font-weight:650}
.tools{display:flex;align-items:center;gap:8px;flex:none;margin-left:auto}
.lang-menu{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:38px;min-width:44px;width:auto;padding:0 12px;border:0;border-radius:var(--r-pill);background:var(--transparent);font-size:14px;color:var(--muted);white-space:nowrap}
.lang:hover{background:rgb(var(--accent-rgb) / .06);color:var(--text)}
.lang__caret{font-size:11px}
.lang-popover{position:absolute;z-index:45;right:0;top:calc(100% + 8px);min-width:176px;padding:8px;background:var(--white);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-float)}
.lang-popover a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-row)}
.lang-popover a:hover,.lang-popover a[aria-current]{background:var(--lavender);color:var(--accent-dark)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:38px;padding:0 20px;border-radius:var(--r-pill);background:var(--text);color:var(--white);font-size:14px;font-weight:650;white-space:nowrap;box-shadow:inset 0 1px 0 rgb(var(--white-rgb) / .18);transition:background-color var(--ease)}
.btn-login:hover{background:var(--accent-dark)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:8px;border-radius:var(--r-row);background:var(--groove);color:var(--text)}
.mobile-nav{display:none}
.nav-veil{position:fixed;z-index:35;inset:var(--header-height) 0 0;background:rgb(var(--text-rgb) / .25)}
.site-footer{padding-top:64px;padding-bottom:28px;background:var(--panel);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr) minmax(0,1fr);gap:48px}
.footer-brand p{max-width:340px;margin-top:20px;color:var(--muted);font-size:var(--text-sm)}
.footer-title{font-size:var(--text-body);margin:0 0 16px}
.footer-links{display:flex;flex-wrap:wrap;gap:4px 18px;list-style:none;padding:0;margin:0}
.footer-links li{margin:0}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--text-sm);color:var(--muted)}
.footer-links a:hover{color:var(--accent-dark)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px}
.footer-languages a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--text-sm)}
.footer-languages a[aria-current]{color:var(--accent-dark);font-weight:var(--weight-bold)}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:24px;padding-top:24px;border-top:1px solid var(--border);font-size:var(--text-sm);color:var(--muted)}
.footer-bottom p{margin:0}
@media(max-width:1360px){:root{--gutter:56px}}
@media(max-width:1180px){
  .topbar__row{gap:16px}
  .mainnav{display:none}
  .menu-toggle{display:inline-flex}
  .tools{margin-left:auto}
  .mobile-nav:not([hidden]){display:block;position:absolute;z-index:42;top:100%;left:0;right:0;background:var(--white);padding:16px var(--gutter) 24px;max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;border-bottom:1px solid var(--border);box-shadow:var(--shadow-float)}
  .mobile-nav ul{list-style:none;padding:0;margin:0}
  .mobile-nav li{margin:0}
  .mobile-nav a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 14px;border-radius:var(--r-row)}
  .mobile-nav a:hover,.mobile-nav a[aria-current]{background:var(--lavender);color:var(--accent-dark)}
  .mobile-languages{margin-top:16px;padding-top:16px;border-top:1px solid var(--border)}
}
@media(max-width:768px){
  :root{--gutter:20px;--text-h1:38px;--text-h2:30px;--text-h3:23px}
  h1{line-height:1.12}
  .section{padding-top:48px;padding-bottom:48px}
  .section--compact{padding-top:28px;padding-bottom:28px}
  .grid,.reading-layout,.help-section,.footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-grid{gap:28px}
  .site-footer{padding-top:40px}
  .surface{padding:24px}
  .decoration-zone{max-width:100%}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none!important}
  .tools{gap:4px;margin-left:auto}
  .topbar__row{gap:8px}
  .lang{padding-inline:8px}
  .btn-login{padding-inline:14px}
  .brand{gap:8px}
  .brand__name{font-size:17px}
  .brand__mark{width:28px;height:28px}
  .panel{padding:20px}
  .footer-bottom{align-items:flex-start;flex-direction:column}
}
@media(max-width:360px){.tools .lang{font-size:12px;padding-inline:5px}.tools{gap:2px}.brand__name{font-size:16px}}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none}
}