:root{
  --bg:#E3E9F1;
  --bg-top:#ECF1F7;
  --bg-bottom:#DCE4EE;
  --panel:#F6F8FC;
  --panel-2:#D6DFEA;
  --tray-top:#F1F4F9;
  --tray-bottom:#E8EEF5;
  --white:#FFFFFF;
  --border:#C8D2DF;
  --border-a60:rgba(200,210,223,.6);
  --line:rgba(200,210,223,.9);
  --accent:#E2492B;
  --accent-dark:#B5361C;
  --accent-2:#F08A5A;
  --text:#131A27;
  --muted:#566175;
  --muted-2:#7A8597;
  --success:#1E8A5A;
  --warn:#C4860C;
  --error:#B4233A;
  --accent-a05:rgba(226,73,43,.05);
  --accent-a06:rgba(226,73,43,.06);
  --accent-a08:rgba(226,73,43,.08);
  --accent-a10:rgba(226,73,43,.10);
  --accent-a14:rgba(226,73,43,.14);
  --accent-a24:rgba(226,73,43,.24);
  --accent2-a05:rgba(240,138,90,.05);
  --accent2-a24:rgba(240,138,90,.24);
  --ink-a06:rgba(19,26,39,.06);
  --ink-a10:rgba(19,26,39,.10);
  --ink-a16:rgba(19,26,39,.16);
  --white-a30:rgba(255,255,255,.3);
  --white-a45:rgba(255,255,255,.45);
  --veil:rgba(19,26,39,.32);
  --flag-red:#D9343C;
  --flag-blue:#22377A;
  --flag-navy:#1B2A63;
  --flag-white:#FFFFFF;
  --clear:transparent;
  --font-display:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,-apple-system,'Segoe UI',sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --font-serif:'Iowan Old Style','Songti SC','Noto Serif SC','Source Han Serif SC',Georgia,serif;
  --r-card:10px;
  --r-tray:20px;
  --r-btn:8px;
  --r-pill:999px;
  --r-dot:50%;
  --r-square:1px;
  --container:1200px;
  --reading:800px;
  --gutter:32px;
  --header-height:64px;
  --anchor-offset:144px;
  --space-1:8px;
  --space-2:16px;
  --space-3:24px;
  --space-4:32px;
  --space-5:40px;
  --space-6:48px;
  --space-8:64px;
  --space-9:72px;
  --shadow-card:0 16px 40px var(--accent-a08);
  --shadow-tray:inset 0 1px 0 var(--white),0 0 0 1px var(--border-a60),0 24px 60px var(--accent-a10);
  --shadow-button:0 10px 26px var(--accent-a24),inset 0 1px 0 var(--white-a30);
  --duration-fast:.18s;
  --duration-reveal:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-padding-top:80px;scroll-behavior:smooth}
html,body{margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
[hidden]{display:none!important}
img,video{max-width:100%;height:auto}
svg{vertical-align:middle}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a{-webkit-tap-highlight-color:var(--accent-a10)}
button{border:0}
a{color:inherit;text-underline-offset:3px}
a,button,summary,input,select,textarea,[tabindex]{touch-action:manipulation}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--accent-dark);outline-offset:3px}
h1,h2,h3,h4,p,ul,ol,blockquote,figure{margin-top:0}
h1,h2,h3{overflow-wrap:break-word;text-wrap:balance}
h1{font-family:var(--font-display);font-size:clamp(52px,4.45vw,64px);line-height:1.1;letter-spacing:-.02em;font-weight:500}
h2{font-family:var(--font-serif);font-size:clamp(28px,3.2vw,40px);line-height:1.25;font-weight:500}
h3{font-family:var(--font-serif);font-size:26px;line-height:1.35;font-weight:500}
p{margin-bottom:var(--space-3)}
small{font-size:.8125em}
code{font-family:var(--font-mono);font-size:.875em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:var(--space-3);border:1px solid var(--border);border-radius:var(--r-card);background:var(--panel);white-space:pre}
pre code{overflow-wrap:normal}
hr{border:0;border-top:1px solid var(--border);margin-block:var(--space-4)}
.container,.wrap{width:100%;max-width:var(--container);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--space-9);padding-bottom:var(--space-9)}
.section-heading{text-align:center;margin-bottom:var(--space-5)}
.section-heading p{color:var(--muted);margin-bottom:0}
.section-heading h2{margin-bottom:var(--space-2)}
.text-accent{color:var(--accent)}
.text-muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.grid-two,.grid-three{display:grid;gap:var(--space-3)}
.grid-two{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
:where(.grid-two,.grid-three,.platforms,.footer-grid)>*{min-width:0}
.card,.panel{padding:var(--space-4);border:1px solid var(--border);border-radius:var(--r-card);background:var(--panel);box-shadow:var(--shadow-card)}
.panel-inset{padding:var(--space-3);border-radius:var(--r-card);background:var(--panel-2)}
.prose{overflow-wrap:break-word}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:var(--space-6)}
.prose h3{margin-top:var(--space-4)}
.prose li+li{margin-top:var(--space-1)}
.sq{display:inline-block;width:10px;height:10px;border-radius:var(--r-square);background:var(--accent);flex-shrink:0}
.ico{width:16px;height:16px;flex-shrink:0;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 26px;border:1px solid var(--clear);border-radius:var(--r-btn);font-size:16px;font-weight:600;line-height:26px;text-decoration:none;white-space:nowrap;flex-shrink:0}
.btn-primary{color:var(--white);background:linear-gradient(105deg,var(--accent) 0%,var(--accent) 52%,var(--accent-2) 135%);box-shadow:var(--shadow-button)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent-dark)}
.btn-primary:active{box-shadow:inset 0 2px 6px var(--ink-a16)}
.btn-ghost,.btn-secondary{color:var(--text);background:var(--white);border:1px solid var(--text)}
.btn-ghost:hover,.btn-secondary:hover{background:var(--panel)}
.btn:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;background:var(--panel-2);color:var(--muted);box-shadow:none;border-color:var(--border)}
.btn-small{min-height:36px;padding:4px 16px;font-size:14px}
.btn-arrow{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}
.cta-row{display:flex;gap:14px;justify-content:center;margin:0 0 24px}
.topbar{background:var(--bg-top);border-bottom:1px solid var(--line);position:relative;z-index:50}
.topbar-in{display:flex;align-items:center;flex-wrap:nowrap;height:var(--header-height)}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);flex-shrink:0}
.brand-mark{width:32px;height:32px;display:block;flex-shrink:0}
.brand-en{font-family:var(--font-display);font-weight:700;font-size:18px;letter-spacing:.01em;line-height:1}
.brand-zh{font-size:14px;font-weight:400;color:var(--muted);line-height:1}
.mainnav{display:flex;align-items:center;flex:1;min-width:0;margin-left:48px}
.mainnav ul{display:flex;align-items:center;gap:28px;list-style:none;margin:0;padding:0}
.mainnav li{min-width:0}
.mainnav a{display:inline-flex;align-items:center;min-height:44px;font-size:15px;color:var(--muted);text-decoration:none;font-weight:400;white-space:nowrap}
.mainnav a:hover{color:var(--text)}
.mainnav a[aria-current="page"]{color:var(--text);font-weight:600}
.topbar-end{margin-left:auto;display:flex;align-items:center;gap:20px;flex-shrink:0}
.lang{font-size:14px;color:var(--muted);white-space:nowrap}
.language-picker{position:relative}
.language-button{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-width:44px;min-height:44px;width:auto;padding:0;background:var(--clear);font-size:14px;color:var(--muted);white-space:nowrap}
.language-button span{white-space:nowrap}
.language-panel{position:absolute;right:0;top:calc(100% + 8px);z-index:70;width:180px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-card)}
.language-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-btn);font-size:14px}
.language-panel a:hover,.language-panel a[aria-current="true"]{background:var(--panel-2)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:36px;padding:0 18px;border-radius:var(--r-btn);background:var(--text);color:var(--white);font-size:14px;font-weight:500;text-decoration:none;white-space:nowrap;box-shadow:0 6px 16px var(--ink-a10)}
.btn-login:hover{background:var(--accent-dark)}
.menu-button{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;background:var(--clear);border:1px solid var(--border);border-radius:var(--r-btn)}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{display:none;position:fixed;top:var(--header-height);right:0;left:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;z-index:45;background:var(--panel);padding:16px var(--gutter) 32px}
.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;text-decoration:none;border-bottom:1px solid var(--border)}
.mobile-drawer a[aria-current]{color:var(--accent-dark);font-weight:600}
.drawer-languages{margin-top:24px;border-top:1px solid var(--border)}
.nav-veil{position:fixed;inset:var(--header-height) 0 0;z-index:40;background:var(--veil);border:0}
html.nav-open{overflow:hidden}
.site-footer{background:var(--tray-bottom);border-top:1px solid var(--border);padding-top:var(--space-6);padding-bottom:var(--space-4)}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:var(--space-6)}
.footer-brand p{max-width:340px;margin-top:var(--space-2);font-size:14px;color:var(--muted)}
.footer-title{font-family:var(--font-body);font-size:15px;font-weight:600;margin-bottom:var(--space-2)}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px;list-style:none;margin:0;padding:0}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;font-size:14px;text-decoration:none;color:var(--muted)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent-dark);text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;padding-block:var(--space-3);margin-top:var(--space-3);border-top:1px solid var(--border)}
.footer-bottom{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:16px;font-size:13px;color:var(--muted);border-top:1px solid var(--border);padding-top:var(--space-3)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.reveal{transition:opacity var(--duration-reveal) ease,transform var(--duration-reveal) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
.decor-section{position:relative;overflow-x:clip;max-width:100%;isolation:isolate}
#server-status{position:relative;display:block;min-width:0;max-width:100%;min-height:48px;overflow:hidden;margin-top:var(--space-3);margin-bottom:var(--space-3)}
#server-status+*{margin-top:var(--space-3)}
@media(min-width:901px){.mobile-drawer,.nav-veil{display:none!important}}
@media(max-width:1280px){
  .mainnav{margin-left:28px}
  .mainnav ul{gap:18px}
  .topbar-end{gap:16px}
}
@media(max-width:1100px){
  .brand-zh{display:none}
  .mainnav{margin-left:24px}
  .mainnav ul{gap:14px}
  .mainnav a{font-size:14px}
}
@media(max-width:900px){
  .mainnav{display:none}
  .topbar-end{margin-left:auto;gap:12px}
  .menu-button{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block}
}
@media(max-width:768px){
  h1{font-size:40px}
  h2{font-size:30px}
  h3{font-size:24px}
  .grid-two,.grid-three{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:24px}
  .section{padding-top:48px;padding-bottom:48px}
  .cta-row{flex-wrap:wrap}
}
@media(max-width:640px){
  :root{--gutter:20px}
  .no-break{white-space:normal}
  h1{font-size:34px}
  .tilt,[data-tilt]{transform:none}
  .decor-section{max-width:100%}
  .card,.panel{padding:24px}
  .brand-en{font-size:16px}
  .brand-mark{width:28px;height:28px}
  .brand{gap:8px}
  .topbar-end{gap:8px;margin-left:auto}
  .language-button{font-size:12px}
  .btn-login{padding:0 12px;font-size:13px}
  .lang{display:none}
}
@media(max-width:360px){
  :root{--gutter:16px}
  .topbar-end{gap:4px}
  .language-button{font-size:11px;gap:2px}
  .brand-en{font-size:15px}
  .brand-mark{width:24px;height:24px}
  .btn-login{padding:0 10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}