:root{
  --bg:#F5F6F9;
  --bg-panel:#FFFFFF;
  --bg-panel-2:#ECEEF4;
  --border:#DCE0EA;
  --border-strong:#C9CFDD;
  --accent:#3049F2;
  --accent-dark:#1F31C4;
  --accent-deep:#2638D6;
  --accent-tint:rgba(48,73,242,.08);
  --accent-tint-2:rgba(48,73,242,.14);
  --accent-soft:rgba(48,73,242,.42);
  --text:#141A2E;
  --text-muted:#5A6278;
  --success:#22B783;
  --success-soft:rgba(34,183,131,.5);
  --success-halo:rgba(34,183,131,.18);
  --warn:#E8A317;
  --error:#E0413A;
  --cta:#FA7F16;
  --cta-deep:#EE6E06;
  --cta-glow:rgba(250,127,22,.28);
  --coral:#FF8A6B;
  --rose:#F28BB8;
  --on-accent:#FFFFFF;
  --on-accent-muted:rgba(255,255,255,.8);
  --on-accent-line:rgba(255,255,255,.18);
  --hero-top:#FFFFFF;
  --hero-bottom:#EDEFF5;
  --dot-page:rgba(48,73,242,.07);
  --dot-panel:rgba(255,255,255,.09);
  --hi-edge:rgba(255,255,255,.6);
  --hi-inset:rgba(255,255,255,.9);
  --switch-off:#D3D8E4;
  --knob-shadow:rgba(20,26,46,.22);
  --veil:rgba(20,26,46,.38);
  --flag-red:#D7263D;
  --flag-white:#FFFFFF;
  --flag-blue:#1E3A8A;
  --flag-green:#129254;
  --flag-edge:rgba(20,26,46,.16);
  --flag-ring:rgba(255,255,255,.85);
  --clear:transparent;
  --shadow-soft:0 18px 48px rgba(48,73,242,.12),0 2px 6px rgba(48,73,242,.06);
  --shadow-panel:0 36px 70px -28px rgba(31,49,196,.45);
  --shadow-window:0 34px 80px rgba(48,73,242,.14),0 26px 60px -12px rgba(14,22,96,.42);
  --shadow-float:0 16px 36px rgba(14,22,96,.28),0 2px 6px rgba(48,73,242,.14);
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Malgun Gothic","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",ui-monospace,Menlo,Consolas,monospace;
  --r-xs:4px;
  --r-sm:6px;
  --r-md:8px;
  --r-lg:10px;
  --r-pill:999px;
  --r-round:50%;
  --gutter:32px;
  --content-width:1280px;
  --header-height:72px;
  --anchor-offset:156px;
  --text-size:16px;
  --small-size:14px;
  --h1-size:clamp(52px,4.6vw,66px);
  --h2-size:clamp(28px,3vw,36px);
  --h3-size:22px;
  --weight-normal:400;
  --weight-medium:500;
  --weight-bold:700;
  --weight-heavy:800;
  --weight-display:900;
  --ease-out:cubic-bezier(.2,.7,.2,1);
  --transition-fast:.18s;
  --transition-reveal:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-height) + 16px)}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-size);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,a,input,select,textarea,summary{-webkit-tap-highlight-color:var(--accent-tint)}
button{color:inherit}
img{max-width:100%;height:auto;display:block}
svg{flex-shrink:0}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--accent);outline-offset:4px}
::selection{background:var(--accent-tint-2);color:var(--text)}
h1,h2,h3{font-family:var(--font-display);line-height:1.2;text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--h1-size);font-weight:var(--weight-display);letter-spacing:-.02em;line-height:1.1;margin:0 0 24px}
h2{font-size:var(--h2-size);font-weight:var(--weight-heavy);letter-spacing:-.02em;margin:0 0 20px}
h3{font-size:var(--h3-size);font-weight:var(--weight-bold);margin:0 0 12px}
p{margin:0 0 20px}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--bg-panel-2);border:1px solid var(--border);border-radius:var(--r-md)}
pre code{white-space:pre;overflow-wrap:normal}
table{border-collapse:collapse}
th{text-align:left}
.grid>*{min-width:0}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter);min-width:0}
.section{padding-top:64px;padding-bottom:64px}
.section-heading{max-width:760px;margin-bottom:28px}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.svg-sprite{position:absolute;width:0;height:0;overflow:hidden}
.card,.surface{background:var(--bg-panel);border-radius:var(--r-lg);border:1px solid var(--border);box-shadow:var(--shadow-soft),inset 0 1px 0 var(--hi-inset);min-width:0}
.card{padding:24px}
.grid{display:grid;gap:24px;grid-template-columns:repeat(3,minmax(0,1fr))}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:12px 28px;border:1.5px solid var(--clear);border-radius:var(--r-sm);font-size:16.5px;font-weight:var(--weight-heavy);letter-spacing:.01em;white-space:nowrap;flex-shrink:0;line-height:1.3;transition:background var(--transition-fast),border-color var(--transition-fast),transform var(--transition-fast)}
.btn svg{width:18px;height:18px}
.btn-primary{background:linear-gradient(180deg,var(--cta),var(--cta-deep));color:var(--on-accent);box-shadow:0 12px 26px var(--cta-glow),inset 0 1px 0 var(--hi-edge)}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);background:var(--cta-deep)}
.btn-ghost,.btn-secondary{background:var(--bg-panel);color:var(--text);border-color:var(--border-strong)}
.btn-ghost:hover,.btn-secondary:hover,.btn-ghost.is-hover{border-color:var(--accent);color:var(--accent)}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;opacity:.6;box-shadow:none}
.btn-small{min-height:40px;padding:8px 16px;font-size:var(--small-size)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.arrow-stroke,.icon-stroke{fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
#site-header{position:sticky;top:0;z-index:100;min-height:var(--header-height);background:var(--bg-panel)}
.topbar-inner{position:relative;z-index:103;max-width:1440px;margin:0 auto;height:var(--header-height);display:flex;align-items:center;flex-wrap:nowrap;gap:24px;padding:0 32px 0 80px;background:var(--bg-panel)}
.brand{display:flex;align-items:center;gap:10px;flex:none;min-height:44px}
.brand-mark{width:34px;height:34px;border-radius:var(--r-md);flex:none}
.brand-en{font-family:var(--font-display);font-weight:var(--weight-heavy);font-size:19px;letter-spacing:-.02em;color:var(--text)}
.brand-zh{font-size:var(--small-size);font-weight:var(--weight-medium);color:var(--text-muted)}
.mainnav{margin-left:28px;flex:1;min-width:0}
.nav-list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.nav-list a{display:block;padding:7px 14px;border-radius:var(--r-pill);font-size:14.5px;font-weight:var(--weight-medium);color:var(--text-muted);white-space:nowrap;min-height:36px}
.nav-list a:hover{color:var(--text)}
.nav-list a[aria-current="page"]{background:var(--accent-tint);color:var(--accent);font-weight:var(--weight-bold);box-shadow:inset 0 0 0 1px var(--accent-tint-2)}
.bar-tools{margin-left:auto;display:flex;align-items:center;gap:14px;flex-shrink:0}
.language-control{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:36px;min-width:44px;width:auto;padding:0 10px;border:0;background:var(--clear);border-radius:var(--r-sm);font-size:var(--small-size);color:var(--text-muted);white-space:nowrap}
.lang span{white-space:nowrap}
.lang svg{width:16px;height:16px}
.language-panel{position:absolute;z-index:110;top:calc(100% + 10px);right:0;min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--r-md);box-shadow:var(--shadow-soft)}
.language-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-xs)}
.language-panel a:hover,.language-panel a[aria-current="true"]{color:var(--accent);background:var(--accent-tint)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:7px 20px;border-radius:var(--r-sm);border:1.5px solid var(--accent);color:var(--accent);font-weight:var(--weight-bold);font-size:14.5px;background:var(--bg-panel);white-space:nowrap}
.btn-login:hover{background:var(--accent);color:var(--on-accent)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--r-sm);background:var(--bg-panel);color:var(--text)}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{display:none;position:fixed;z-index:102;top:var(--header-height);left:0;right:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:20px var(--gutter) 40px}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;border-radius:var(--r-sm);color:var(--text-muted)}
.mobile-drawer a[aria-current]{background:var(--accent-tint);color:var(--accent)}
.drawer-languages{border-top:1px solid var(--border);margin-top:20px;padding-top:16px}
.menu-veil{display:none;position:fixed;z-index:101;inset:var(--header-height) 0 0;background:var(--veil)}
html.nav-open{overflow:hidden}
.site-footer{border-top:1px solid var(--border);background:var(--bg-panel-2);padding-top:48px;padding-bottom:28px}
.footer-grid{display:grid;grid-template-columns:1.15fr 1fr 1fr;gap:40px}
.footer-brand p{color:var(--text-muted);margin-top:16px;max-width:32em}
.footer-title{font-size:var(--small-size);font-weight:var(--weight-heavy);margin:0 0 12px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:30px;font-size:var(--small-size)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:28px;padding-top:20px;border-top:1px solid var(--border)}
.footer-bottom{display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-top:16px;font-size:var(--small-size);color:var(--text-muted)}
.footer-legal{display:flex;gap:24px;flex-wrap:wrap}
.reveal{transition:opacity var(--transition-reveal) var(--ease-out),transform var(--transition-reveal) var(--ease-out)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:120px;max-width:100%;min-width:0;overflow:hidden;margin-block:24px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:28px}
.prose{max-width:820px;min-width:0;overflow-wrap:break-word}
.prose p{line-height:1.85}
.prose h2{margin-top:48px}
.prose h3{margin-top:28px}
.prose a:not(.btn){color:var(--accent);text-decoration:underline;text-underline-offset:3px}
.prose li{margin-bottom:10px}
.prose img{border-radius:var(--r-md)}
[data-counter]{display:inline-block;min-width:3ch;font-family:var(--font-mono);font-variant-numeric:tabular-nums}
@media(max-width:1320px){
  .topbar-inner{padding-inline:32px;gap:16px}
  .mainnav{margin-left:8px}
  .nav-list a{padding-inline:10px}
  .bar-tools{gap:8px}
}
@media(max-width:1180px){
  .mainnav{display:none}
  .menu-toggle{display:inline-flex}
  .bar-tools{margin-left:auto}
  html.nav-open .mobile-drawer,html.nav-open .menu-veil{display:block}
}
@media(min-width:1181px){
  html.nav-open{overflow:auto}
}
@media(max-width:768px){
  :root{--gutter:20px;--header-height:64px;--h1-size:38px;--h2-size:28px}
  .topbar-inner{padding-inline:16px;gap:12px}
  .bar-tools{margin-left:auto;gap:6px}
  .brand-zh,.lang span{display:none}
  .section{padding-top:40px;padding-bottom:40px}
  .grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .footer-bottom{flex-direction:column}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .decoration,.panel-glow,.stripe-halo{max-width:100%}
}
@media(max-width:380px){
  :root{--gutter:16px}
  .topbar-inner{gap:8px;padding-inline:12px}
  .brand{gap:6px}
  .brand-en{font-size:16px}
  .brand-mark{width:28px;height:28px}
  .btn-login{padding-inline:10px;font-size:13px}
  .bar-tools{gap:2px}
  .lang{padding-inline:5px;min-width:32px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}