:root{
  --bg:#EAEEF6;
  --bg-top:#F2F4FA;
  --bg-bottom:#E3E8F2;
  --bg-panel:#F7F9FD;
  --bg-panel-2:#DDE3F0;
  --border:#CDD5E5;
  --accent:#D23C61;
  --accent-dark:#A62647;
  --text:#17161F;
  --text-muted:#5A6074;
  --success:#2E8B5E;
  --warn:#C08316;
  --error:#C2392E;
  --ink:#111018;
  --white:#FFFFFF;
  --black:#000000;
  --ann:#C4CFF3;
  --card-blue:#8FA5DE;
  --card-olive:#B1A877;
  --card-brick:#6B2A22;
  --card-butter:#EFDFA6;
  --card-blue-deep:#6175BF;
  --panel-cream:#FBF4E1;
  --ink-blue:#2C3B78;
  --ink-olive:#4A4528;
  --ink-tokyo:#B1461E;
  --ink-brick:#6B2A22;
  --flag-red:#D8283E;
  --flag-white:#FFFFFF;
  --flag-blue:#253A7A;
  --flag-black:#1C1B1F;
  --flag-gold:#F1C12E;
  --transparent:transparent;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --r-card:28px;
  --r-inner:18px;
  --r-sm:12px;
  --r-pill:999px;
  --r-circle:50%;
  --r-line:2px;
  --shell:1440px;
  --reading:860px;
  --gutter:64px;
  --head-height:72px;
  --anchor-space:92px;
  --toc-space:156px;
  --weight-body:400;
  --weight-medium:500;
  --weight-semibold:600;
  --weight-bold:700;
  --weight-heavy:800;
  --weight-display:900;
  --size-body:16px;
  --size-small:14px;
  --size-h1:clamp(52px,4.5vw,66px);
  --size-h2:clamp(28px,3vw,44px);
  --size-h3:22px;
  --shadow-panel:0 24px 48px color-mix(in srgb,var(--card-blue-deep) 12%,var(--transparent));
  --shadow-button:0 14px 28px -12px color-mix(in srgb,var(--ink) 55%,var(--transparent));
  --time-fast:.2s;
  --time-reveal:.35s;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-space);scroll-behavior:smooth}
body{font-family:var(--font-body);font-size:var(--size-body);font-weight:var(--weight-body);color:var(--text);background:var(--bg);line-height:1.6;overflow-x:clip;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,summary,a{-webkit-tap-highlight-color:var(--transparent)}
button{border:0}
ul{list-style:none}
img{display:block;max-width:100%;height:auto}
svg{display:block;flex-shrink:0}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px}
::selection{background:var(--ann);color:var(--ink)}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-heavy);line-height:1.2;text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--size-h1);line-height:1.1;letter-spacing:-.02em}
h2{font-size:var(--size-h2);letter-spacing:-.02em}
h3{font-size:var(--size-h3)}
p{overflow-wrap:break-word}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;border-radius:var(--r-inner);background:var(--bg-panel-2);font-family:var(--font-mono)}
pre code{overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
.shell,.wrap{width:100%;max-width:var(--shell);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:calc(var(--reading) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:72px;padding-bottom:72px}
.section-heading{margin-bottom:32px}
.section-heading p{margin-top:16px;max-width:65ch;color:var(--text-muted)}
.prose{min-width:0;line-height:1.85}
.prose p,.prose ul,.prose ol,.prose pre,.prose table{margin-block:20px}
.prose h2{margin-top:52px;margin-bottom:20px}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose a:not(.btn){text-decoration:underline;text-underline-offset:4px;color:var(--ink-blue)}
.prose li+li{margin-top:8px}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid>*{min-width:0}
.card,.panel{min-width:0;padding:28px;border-radius:var(--r-card);background:var(--bg-panel);box-shadow:inset 0 1px 0 var(--white),var(--shadow-panel)}
.panel-inset{min-width:0;padding:24px;border-radius:var(--r-inner);background:var(--bg-panel-2)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono)}
.no-break{white-space:nowrap}
.br-m{display:none}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.ic{width:18px;height:18px;flex-shrink:0}
.ico-s{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.f-red{fill:var(--flag-red)}
.f-white{fill:var(--flag-white)}
.f-blue{fill:var(--flag-blue)}
.f-black{fill:var(--flag-black)}
.f-gold{fill:var(--flag-gold)}
.flag{width:21px;height:14px;overflow:hidden;border-radius:var(--r-line);flex-shrink:0}
.flag-edge{fill:none;stroke:var(--border);stroke-width:1}
.btn,.btn-login{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;white-space:nowrap;border-radius:var(--r-pill);font-weight:var(--weight-bold)}
.btn{gap:8px;min-height:52px;padding:12px 30px;font-size:16px;letter-spacing:.01em;line-height:1.4;transition:transform var(--time-fast),background-color var(--time-fast),box-shadow var(--time-fast)}
.btn-primary{background:var(--ink);color:var(--white);box-shadow:var(--shadow-button)}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);box-shadow:0 18px 32px -12px color-mix(in srgb,var(--ink) 60%,var(--transparent))}
.btn-ghost,.btn-secondary{background:var(--transparent);color:var(--text);box-shadow:inset 0 0 0 1.5px var(--text)}
.btn-ghost:hover,.btn-secondary:hover,.btn-ghost.is-hover{background:var(--bg-panel)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none;cursor:not-allowed;transform:none}
.btn.is-focus{outline:2px solid var(--accent-dark);outline-offset:3px}
.cta-row{display:flex;flex-wrap:wrap;justify-content:center;gap:12px;margin-bottom:22px}
.btn-login{height:42px;padding-inline:24px;background:var(--ink);color:var(--white);font-size:15px;transition:transform var(--time-fast)}
.btn-login:hover{transform:translateY(-1px)}
.top-zone{background:linear-gradient(180deg,var(--bg-top) 0%,var(--bg-bottom) 100%);overflow-x:clip;max-width:100%}
.ann-toggle{position:absolute;opacity:0;width:1px;height:1px}
.ann{position:relative;min-height:40px;display:flex;align-items:center;justify-content:center;gap:10px;padding:0 64px;background:var(--ann);font-size:14px;font-weight:var(--weight-medium);color:var(--text);text-align:center}
.ann a{font-weight:var(--weight-bold);text-decoration:underline;text-decoration-thickness:1.5px;text-underline-offset:3px;min-height:24px}
.ann-close{position:absolute;right:20px;top:50%;width:32px;height:32px;margin-top:-16px;display:grid;place-items:center;border-radius:var(--r-circle);cursor:pointer;color:var(--text);background:var(--transparent)}
.ann-close:hover{background:color-mix(in srgb,var(--white) 45%,var(--transparent))}
.ann-toggle:focus-visible+.ann .ann-close{outline:2px solid var(--text);outline-offset:2px}
.ann-toggle:checked+.ann{display:none}
#site-header{position:relative;z-index:100;min-height:var(--head-height)}
.site-head{height:var(--head-height);position:relative;z-index:100;background:var(--transparent)}
.head-in{height:100%;display:flex;align-items:center;gap:24px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;flex-shrink:0}
.brand img{width:30px;height:30px;flex-shrink:0}
.brand-en{font-family:var(--font-display);font-size:21px;font-weight:var(--weight-heavy);letter-spacing:-.025em;line-height:1}
.brand-zh{font-size:13px;font-weight:var(--weight-medium);color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border);white-space:nowrap}
.nav{display:flex;align-items:center;justify-content:center;flex:1;min-width:0}
.nav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.nav-link,.nav-more-btn{position:relative;display:inline-flex;align-items:center;gap:4px;min-height:40px;padding:0 14px;border:0;background:var(--transparent);font:inherit;font-size:15px;font-weight:var(--weight-medium);color:var(--text);border-radius:var(--r-pill);white-space:nowrap}
.nav-link:hover,.nav-more-btn:hover{background:color-mix(in srgb,var(--bg-panel-2) 70%,var(--transparent))}
.nav-link[aria-current="page"],.nav-more-btn.is-active{font-weight:var(--weight-bold)}
.nav-link[aria-current="page"]::after{content:"";position:absolute;left:14px;right:14px;bottom:6px;height:2px;border-radius:var(--r-line);background:var(--text)}
.nav-more{position:relative}
.nav-more-btn{list-style:none;cursor:pointer}
.nav-more-btn::-webkit-details-marker{display:none}
.menu{position:absolute;top:100%;left:50%;width:248px;padding-top:10px;transform:translateX(-50%);z-index:120;display:none}
.nav-more.is-open>.menu,.nav-more[open]>.menu{display:block}
.menu-in{padding:10px;border-radius:var(--r-inner);background:var(--bg-panel);box-shadow:0 24px 48px color-mix(in srgb,var(--card-blue-deep) 16%,var(--transparent)),0 0 0 1px var(--border)}
.menu-group+.menu-group{margin-top:6px;padding-top:6px;border-top:1px solid var(--bg-panel-2)}
.menu-label{display:block;padding:6px 12px 4px;font-family:var(--font-mono);font-size:10.5px;letter-spacing:.1em;color:var(--text-muted)}
.menu a{display:flex;align-items:center;min-height:40px;padding:8px 12px;border-radius:var(--r-sm);font-size:14px;font-weight:var(--weight-semibold)}
.menu a:hover,.menu a[aria-current="page"]{background:var(--bg-panel-2)}
.head-right{display:flex;align-items:center;gap:8px;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;width:auto;min-height:40px;padding:0 12px;border:0;background:var(--transparent);font:inherit;font-size:14px;font-weight:var(--weight-medium);border-radius:var(--r-pill);white-space:nowrap;cursor:pointer}
.lang-text{white-space:nowrap}
.lang:hover{background:var(--bg-panel-2)}
.lang-panel{display:none;position:absolute;top:calc(100% + 10px);right:0;z-index:150;width:190px;padding:8px;border-radius:var(--r-inner);background:var(--bg-panel);box-shadow:var(--shadow-panel),0 0 0 1px var(--border)}
.lang-box.is-open .lang-panel,.lang-box[open] .lang-panel{display:block}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 14px;border-radius:var(--r-sm)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--bg-panel-2);font-weight:var(--weight-semibold)}
.lang-box>summary{list-style:none}
.lang-box>summary::-webkit-details-marker{display:none}
.burger{display:none;min-width:44px;min-height:44px;align-items:center;justify-content:center;flex-direction:column;gap:5px;background:var(--transparent);border-radius:var(--r-sm)}
.burger-line{display:block;width:20px;height:2px;background:currentColor;border-radius:var(--r-line)}
.nav-drawer{display:none;position:fixed;left:0;right:0;top:var(--head-height);height:calc(100dvh - var(--head-height));max-height:calc(100dvh - var(--head-height));overflow-y:auto;overscroll-behavior:contain;z-index:90;background:var(--bg-panel);padding:20px var(--gutter) 40px}
.nav-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-sm)}
.nav-drawer a:hover,.nav-drawer a[aria-current="page"]{background:var(--bg-panel-2);font-weight:var(--weight-bold)}
.drawer-languages{margin-top:20px;padding-top:20px;border-top:1px solid var(--border)}
.drawer-label{display:block;padding:8px 16px;font-size:12px;color:var(--text-muted)}
.nav-veil{display:none;position:fixed;inset:var(--head-height) 0 0;z-index:80;background:color-mix(in srgb,var(--ink) 25%,var(--transparent))}
html.nav-open{overflow:hidden}
.hero{position:relative;padding-top:32px;overflow-x:clip;max-width:100%}
.hero-copy{position:relative;z-index:5;display:flex;flex-direction:column;align-items:center;text-align:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;min-height:28px;padding:3px 13px 3px 8px;margin-bottom:16px;border-radius:var(--r-pill);background:var(--bg-panel);box-shadow:0 0 0 1px var(--border),0 8px 18px -10px color-mix(in srgb,var(--card-blue-deep) 30%,var(--transparent));font-size:12.5px;font-weight:var(--weight-semibold)}
.eyebrow-dots{display:flex;gap:3px;flex-shrink:0}
.eyebrow-dots i{width:7px;height:7px;border-radius:var(--r-circle)}
.eyebrow-dots i:nth-child(1){background:var(--card-blue)}
.eyebrow-dots i:nth-child(2){background:var(--card-olive)}
.eyebrow-dots i:nth-child(3){background:var(--card-brick)}
.eyebrow-dots i:nth-child(4){background:var(--card-butter)}
.eyebrow-sep{color:var(--text-muted)}
.hero h1{font-size:var(--size-h1);font-weight:var(--weight-heavy);line-height:1.1;letter-spacing:-.02em;color:var(--text);margin-bottom:14px}
.hero h1 .kw{color:var(--accent)}
.lede{font-size:17px;line-height:1.65;color:var(--text-muted);margin-bottom:24px}
.lede strong{color:var(--text);font-weight:var(--weight-bold)}
.facts{display:flex;flex-direction:column;align-items:center;gap:8px}
.chip-row{display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:8px}
.row-label{font-family:var(--font-mono);font-size:10.5px;font-weight:var(--weight-semibold);letter-spacing:.12em;color:var(--text-muted);margin-right:4px}
.chip{display:inline-flex;align-items:center;gap:6px;min-height:28px;padding:5px 12px 5px 10px;border-radius:var(--r-pill);background:color-mix(in srgb,var(--bg-panel) 72%,var(--transparent));box-shadow:inset 0 0 0 1px var(--border);font-size:12.5px;font-weight:var(--weight-medium);color:var(--text);line-height:1.35;max-width:100%;overflow-wrap:anywhere}
.chip .ic{width:14px;height:14px;color:var(--text-muted)}
.chip .flag{width:21px;height:14px}
.trust .chip{background:var(--bg-panel);font-weight:var(--weight-semibold)}
.trust .chip .ic{color:var(--text)}
.site-footer{padding-top:56px;padding-bottom:28px;background:var(--bg-panel-2);border-radius:var(--r-card) var(--r-card) 0 0;box-shadow:inset 0 1px 0 var(--white)}
.footer-grid{display:grid;grid-template-columns:1.35fr 1fr 1fr 1fr;gap:40px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:18px;max-width:30ch;color:var(--text-muted);font-size:14px}
.footer-title{font-size:14px;font-weight:var(--weight-bold);margin-bottom:12px}
.footer-links{display:grid;gap:6px}
.footer-links a{display:inline-flex;align-items:center;min-height:28px;font-size:14px;overflow-wrap:anywhere}
.footer-links a:hover{text-decoration:underline;text-underline-offset:4px}
.footer-bottom{display:flex;align-items:center;flex-wrap:wrap;gap:12px 24px;border-top:1px solid var(--border);padding-top:24px;margin-top:40px;font-size:12px;color:var(--text-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px}
.reveal{transition:opacity var(--time-reveal) ease,transform var(--time-reveal) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
.stat-number,[data-counter]{font-variant-numeric:tabular-nums;display:inline-block;min-width:3ch;text-align:right;font-family:var(--font-mono)}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:32px}
@media(max-width:1180px){
  :root{--gutter:40px}
  .nav-link,.nav-more-btn{padding-inline:10px}
  .brand-zh{display:none}
  .head-in{gap:16px}
}
@media(max-width:1080px){
  .nav{display:none}
  .head-right{margin-left:auto}
  .burger{display:flex}
  html.nav-open .nav-drawer{display:block}
  html.nav-open .nav-veil{display:block}
  .site-head{background:var(--bg-top)}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--size-h1:38px}
  .grid{grid-template-columns:1fr}
  .hero h1{font-size:38px}
  .section{padding-top:48px;padding-bottom:48px}
}
@media(max-width:640px){
  :root{--gutter:20px;--head-height:64px;--anchor-space:80px;--toc-space:140px;--size-h1:32px}
  .no-break{white-space:normal}
  .br-m{display:revert}
  .br-d{display:none}
  .ann{padding:8px 48px;font-size:12.5px;flex-wrap:wrap;gap:4px 8px}
  .ann-close{right:8px}
  .head-in{gap:8px}
  .head-right{gap:4px;margin-left:auto}
  .brand{gap:6px}
  .brand img{width:25px;height:25px}
  .brand-en{font-size:18px}
  .lang{padding-inline:6px}
  .lang-text{display:none}
  .btn-login{height:38px;padding-inline:18px;font-size:14px}
  .hero{padding-top:24px}
  .hero h1{font-size:32px;line-height:1.18}
  .lede{font-size:15px}
  .chip-row{gap:6px}
  .chip{font-size:11.5px;padding-inline:8px}
  .cta-row{gap:10px}
  .btn{padding-inline:24px}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .footer-bottom{align-items:flex-start;flex-direction:column}
  .tilt,[data-tilt]{transform:none}
  .card,.panel{padding:22px}
}
@media(max-width:359px){
  :root{--gutter:16px}
  .brand-en{font-size:16px}
  .brand img{width:23px;height:23px}
  .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{opacity:1;transform:none}
}