:root{
  --bg:#F5EFE3;
  --bg-panel:#FFFBF4;
  --bg-panel-2:#ECE4D3;
  --border:#DDD2BE;
  --border-soft:#E8DFCF;
  --accent:#5B47A6;
  --accent-dark:#3D2E78;
  --accent-2:#8A78D0;
  --text:#2A231B;
  --text-hover:#3B3227;
  --text-muted:#6E6355;
  --text-faint:#988C7B;
  --success:#2F7D4F;
  --warn:#B7791F;
  --error:#B83A2E;
  --hero-top:#FAF6EE;
  --hero-bottom:#EFE7D7;
  --row:#FFFFFF;
  --on-dark:#FFFBF4;
  --on-dark-line:rgba(255,251,244,.28);
  --hairline:rgba(42,35,27,.08);
  --side-on:rgba(42,35,27,.07);
  --grp-bg:rgba(42,35,27,.045);
  --chrome-dot:#CBBFA9;
  --band-tint:rgba(138,120,208,.075);
  --sel-fill:linear-gradient(90deg,rgba(91,71,166,.085),rgba(138,120,208,.035));
  --sel-glow:0 6px 16px -8px rgba(91,71,166,.28);
  --kw-block:linear-gradient(90deg,rgba(91,71,166,.30),rgba(138,120,208,.24));
  --glint:linear-gradient(90deg,rgba(138,120,208,0),rgba(138,120,208,.75) 42%,rgba(91,71,166,.55) 68%,rgba(138,120,208,0));
  --glint-wash:linear-gradient(180deg,rgba(138,120,208,.085),rgba(138,120,208,0) 104px);
  --hi-edge:inset 0 1px 0 rgba(255,255,255,.78);
  --shadow-lift:0 1px 2px rgba(61,46,120,.06),0 14px 28px -14px rgba(91,71,166,.12),0 44px 100px -18px rgba(91,71,166,.12);
  --shadow-float:0 2px 4px rgba(61,46,120,.06),0 20px 44px -12px rgba(91,71,166,.16);
  --shadow-seg:0 1px 2px rgba(42,35,27,.10);
  --mask-on:#FFFFFF;
  --mask-off:#000000;
  --flag-red:#C2453A;
  --flag-white:#FFFDF8;
  --flag-blue:#2E3F78;
  --flag-navy:#25306A;
  --flag-edge:rgba(42,35,27,.18);
  --clear:transparent;
  --radius:6px;
  --radius-sm:4px;
  --radius-inline:2px;
  --radius-round:50%;
  --radius-button:0;
  --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,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --w:1280px;
  --gutter:80px;
  --space-unit:8px;
  --section-space:80px;
  --anchor-offset:80px;
  --toc-offset:16px;
  --toc-landing:96px;
  --ease-out:cubic-bezier(.2,.7,.2,1);
  --duration-fast:200ms;
  --duration-reveal:600ms;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:15px;line-height:1.6;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
p{margin:0}
h1,h2,h3{font-family:var(--font-display);font-weight:400;overflow-wrap:break-word;text-wrap:balance}
h1{font-size:clamp(52px,4.45vw,64px);line-height:1.1;letter-spacing:-.02em}
h2{margin:0 0 24px;font-size:36px;line-height:1.25;letter-spacing:-.015em}
h3{margin:0 0 16px;font-size:23px;line-height:1.35}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
:where(button,summary){min-height:24px}
[hidden]{display:none!important}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere;word-break:break-word}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--bg-panel-2);border:1px solid var(--border);border-radius:var(--radius)}
pre code{overflow-wrap:normal;word-break:normal;white-space:pre}
.wrap{width:100%;max-width:calc(var(--w) + var(--gutter) * 2);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.reading-wrap{max-width:900px;margin-inline:auto;min-width:0}
.prose{min-width:0;overflow-wrap:break-word;line-height:1.85}
.prose p,.prose ul,.prose ol,.prose blockquote{margin-top:0;margin-bottom:24px}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose li+li{margin-top:8px}
.prose a{text-underline-offset:4px}
.prose img{border-radius:var(--radius)}
.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}
.sr-defs{position:absolute;width:0;height:0;overflow:hidden}
.mono-label{font-family:var(--font-mono);font-size:11px;font-weight:500;letter-spacing:.16em;text-transform:uppercase;color:var(--text-faint);line-height:1}
.ico{flex:none;width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.4;stroke-linecap:round;stroke-linejoin:round}
.num{font-family:var(--font-mono);font-weight:500;letter-spacing:.02em;font-variant-numeric:tabular-nums}
.muted{color:var(--text-muted)}
.panel{min-width:0;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--hi-edge);padding:24px}
.panel-lift{box-shadow:var(--shadow-lift),var(--hi-edge)}
.decorated,.tilt-zone{position:relative;overflow-x:clip;max-width:100%}
.btn,.btn-primary,.btn-secondary,.btn-main,.login{display:inline-flex;align-items:center;justify-content:center;min-height:44px;gap:12px;padding:12px 22px;border:1px solid var(--text);border-radius:var(--radius-button);text-decoration:none;font-weight:500;flex-shrink:0;white-space:nowrap;max-width:100%;transition:background-color var(--duration-fast),color var(--duration-fast)}
.btn,.btn-primary,.btn-main,.login{background:var(--text);color:var(--on-dark)}
.btn:hover,.btn-primary:hover,.btn-main:hover,.login:hover{background:var(--text-hover)}
.btn-secondary{background:var(--clear);color:var(--text)}
.btn-secondary:hover{background:var(--bg-panel-2)}
.btn:disabled,.btn-primary:disabled,.btn-secondary:disabled,.btn[aria-disabled="true"]{opacity:.5;pointer-events:none}
.btn-main{height:52px;padding:0 22px 0 24px;gap:16px;font-size:15.5px;border:0}
.btn-tag{padding-left:16px;border-left:1px solid var(--on-dark-line);font-family:var(--font-mono);font-size:11.5px;letter-spacing:.16em;line-height:20px}
.btn-link{display:inline-flex;align-items:center;min-height:28px;font-size:15.5px;font-weight:500;color:var(--text);text-decoration:none;padding-bottom:4px;border-bottom:1.5px solid var(--text)}
.btn-link:hover{color:var(--text-muted);border-color:var(--text-muted)}
.cta-row{display:flex;align-items:center;gap:32px;flex-wrap:wrap}
.notice{background:var(--text);color:var(--on-dark)}
.notice-in{display:flex;align-items:center;justify-content:center;gap:16px;min-height:36px;font-size:13.5px;letter-spacing:.01em}
.notice a{display:inline-flex;align-items:center;min-height:24px;color:var(--on-dark);text-decoration:underline;text-underline-offset:4px;text-decoration-thickness:1px}
.notice a:hover{text-decoration-thickness:2px}
.screen{background:linear-gradient(180deg,var(--hero-top) 0%,var(--hero-bottom) 100%)}
.topbar{position:relative;z-index:20;border-bottom:1px solid var(--hairline);background:var(--hero-top)}
.screen>.topbar{background:var(--clear)}
.topbar-in{position:relative;display:flex;align-items:center;gap:40px;min-height:64px}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;flex:none;min-height:30px}
.brand-mark{width:30px;height:30px;display:block}
.brand-word{font-family:var(--font-display);font-size:18px;font-weight:600;letter-spacing:.02em}
.brand-zh{font-weight:400;color:var(--text-muted)}
.tabs{min-width:0}
.tabs ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;white-space:nowrap}
.tabs a{position:relative;display:block;padding:0 13px;line-height:64px;font-size:14.5px;color:var(--text-muted);text-decoration:none}
.tabs a::after{content:"";position:absolute;left:13px;right:13px;bottom:-1px;height:2px;background:var(--text);transform:scaleX(0);transform-origin:left center;transition:transform var(--duration-fast)}
.tabs a:hover{color:var(--text)}
.tabs a:hover::after{transform:scaleX(.35)}
.tabs a[aria-current="page"]{color:var(--text);font-weight:500}
.tabs a[aria-current="page"]::after{transform:scaleX(1)}
.topbar-end{display:flex;align-items:center;gap:8px;margin-left:auto;flex:none}
.lang-control{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:44px;width:auto;height:36px;padding:0 12px;border:0;background:var(--clear);font:inherit;font-size:14px;color:var(--text-muted);cursor:pointer}
.lang span{white-space:nowrap}
.lang:hover{color:var(--text)}
.login{height:36px;min-height:36px;padding:0 20px;font-size:14px;border:0}
.language-menu{position:absolute;right:0;top:calc(100% + 8px);min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-float);z-index:24}
.language-menu a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none}
.language-menu a:hover,.language-menu a[aria-current]{background:var(--bg-panel-2)}
.menu-toggle{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid var(--border);background:var(--bg-panel);border-radius:var(--radius);font-size:22px}
.mobile-drawer{display:none}
.site-footer{border-top:1px solid var(--border);background:var(--bg-panel-2);padding-top:56px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.35fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:340px;color:var(--text-muted)}
.footer-heading{font-family:var(--font-mono);font-size:12px;font-weight:500;letter-spacing:.12em;text-transform:uppercase;margin:0 0 16px}
.footer-links{display:grid;gap:4px;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;padding-block:2px;text-decoration:none;color:var(--text-muted)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{text-decoration:underline;color:var(--text)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:32px}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;border-top:1px solid var(--border);padding-top:24px;margin-top:24px;font-size:13px;color:var(--text-muted)}
.footer-legal{display:flex;gap:24px;flex-wrap:wrap}
.reveal{transition:opacity var(--duration-reveal) var(--ease-out),transform var(--duration-reveal) var(--ease-out)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:flow-root;min-height:160px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:32px}
@media(max-width:1200px){
  :root{--gutter:40px}
  .topbar-in{gap:24px}
  .tabs a{padding-inline:10px}
  .tabs a::after{left:10px;right:10px}
}
@media(max-width:1024px){
  .topbar-in{flex-wrap:wrap;gap:0 24px;padding-top:12px}
  .tabs{order:3;width:100%;overflow-x:auto}
  .tabs a{line-height:44px}
  .footer-grid{gap:32px}
}
@media(max-width:768px){
  :root{--section-space:56px}
  h1{font-size:40px}
  h2{font-size:30px}
  .topbar-in{flex-wrap:nowrap;padding-top:0;gap:12px;min-height:64px}
  .topbar-end{margin-left:auto;gap:4px}
  .topbar-in>.tabs{display:none}
  .menu-toggle{display:inline-flex}
  .mobile-drawer:not([hidden]){display:block;position:absolute;top:100%;left:0;right:0;z-index:25;background:var(--bg-panel);border-top:1px solid var(--border);border-bottom:1px solid var(--border);padding:12px var(--gutter) 24px;max-height:calc(100dvh - 100px);overflow-y:auto;overscroll-behavior:contain;box-shadow:var(--shadow-float)}
  .mobile-drawer ul{list-style:none;margin:0;padding:0}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 12px;text-decoration:none;border-bottom:1px solid var(--border-soft)}
  .mobile-drawer a[aria-current]{background:var(--bg-panel-2);font-weight:500}
  .mobile-drawer .footer-heading{margin-top:24px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:20px}
  .no-break{white-space:normal}
  .notice-in{flex-wrap:wrap;gap:4px 12px;padding-top:8px;padding-bottom:8px;font-size:12.5px;text-align:center}
  .lang span{display:none}
  .lang{padding-inline:8px}
  .login{padding-inline:14px}
  .brand-word{font-size:17px}
  .brand{gap:8px}
  .topbar-in{gap:8px}
  .tilt,.float-refund,.float-signup{transform:none}
  .decorated>*{max-width:100%}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
  .cta-row{gap:20px 28px}
  pre{padding:16px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}