:root {
  --bg: #FFFFFF;
  --bg-panel: #F6F7F7;
  --bg-panel-2: #EDEFEF;
  --border: #E3E5E6;
  --border-strong: #D3D7D9;
  --accent: #0A9396;
  --accent-dark: #06696B;
  --accent-soft: #E4F2F2;
  --accent-on-dark: #3DB7B9;
  --accent-tint-dark: rgba(10,147,150,.18);
  --amber: #FFC83D;
  --text: #111416;
  --text-muted: #5F676B;
  --text-faint: #8C9396;
  --success: #2FB36B;
  --success-halo: rgba(47,179,107,.22);
  --warn: #E3A008;
  --error: #D64545;
  --ink: #111416;
  --ink-hover: #2A3034;
  --on-ink: #FFFFFF;
  --win: #0F1214;
  --win-2: #181C1F;
  --win-3: #20252A;
  --win-line: #262B2E;
  --win-text: #E7EAEB;
  --win-muted: #8B9498;
  --win-dim: #4E565A;
  --win-direct: #C9CFD1;
  --win-key: #7FD0D2;
  --dot-a: #5E4A4A;
  --dot-b: #5E5843;
  --dot-c: #44564A;
  --clear: transparent;
  --veil: rgba(17,20,22,.28);
  --shadow-window: 0 48px 90px -48px rgba(17,20,22,.34), 0 2px 8px rgba(17,20,22,.04);
  --shadow-btn: 0 1px 2px rgba(17,20,22,.10);
  --shadow-float: 0 12px 32px rgba(17,20,22,.12);
  --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-xl: 28px;
  --r-lg: 16px;
  --r-md: 12px;
  --r-sm: 9px;
  --r-xs: 6px;
  --r-code: 8px;
  --r-mobile: 20px;
  --r-pill: 999px;
  --r-round: 50%;
  --wrap: 1180px;
  --wrap-nav: 1280px;
  --read: 800px;
  --gutter: 32px;
  --header-height: 76px;
  --fs-xs: 12px;
  --fs-small: 13px;
  --fs-label: 12.5px;
  --fs-badge: 13.5px;
  --fs-ui: 14px;
  --fs-nav: 15px;
  --fs-body: 16px;
  --fs-lede: 17px;
  --fs-link: 19px;
  --fs-card: 20px;
  --fs-h3: 24px;
  --fs-h2: clamp(26px,3vw,36px);
  --fs-h1: clamp(34px,3.6vw,48px);
  --fs-statement: clamp(22px,2.4vw,34px);
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --weight-heavy: 800;
  --weight-display: 900;
  --leading-body: 1.6;
  --leading-title: 1.15;
  --tracking-title: -.02em;
  --speed: .15s;
  --reveal-speed: .55s;
  --tab-cycle: 8s;
  --layer-veil: 30;
  --layer-header: 40;
  --layer-menu: 45;
  --layer-fab: 20;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 24px; }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: var(--weight-normal) var(--fs-body)/var(--leading-body) var(--font-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
img, svg { vertical-align: middle; max-width: 100%; }
img { height: auto; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button, a { -webkit-tap-highlight-color: var(--clear); }
a { color: inherit; text-decoration: none; }
button { color: inherit; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
::selection { background: var(--accent-soft); color: var(--text); }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  line-height: var(--leading-title);
  letter-spacing: var(--tracking-title);
  text-wrap: balance;
}
h1 { font-size: var(--fs-h1); font-weight: var(--weight-display); }
h2 { font-size: var(--fs-h2); font-weight: var(--weight-display); }
h3 { font-size: var(--fs-h3); font-weight: var(--weight-heavy); }
p { margin: 0 0 1.25em; }
strong { font-weight: var(--weight-bold); }
small { font-size: var(--fs-small); }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 24px;
  border: 1px solid var(--win-line);
  border-radius: var(--r-lg);
  background: var(--win);
  color: var(--win-text);
  font-size: var(--fs-small);
  line-height: 1.9;
  tab-size: 2;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
hr { border: 0; border-top: 1px solid var(--border); margin-block: 40px; }
.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }
.wrap--flush { max-width: calc(var(--wrap) + var(--gutter) * 2); }
.reading { max-width: calc(var(--read) + var(--gutter) * 2); }
.section { padding-top: 96px; padding-bottom: 96px; }
.section__head { max-width: 720px; margin-bottom: 40px; }
.section__head h2 { margin: 0 0 18px; }
.section__head p, .muted { color: var(--text-muted); }
.section--panel { background: var(--bg-panel); color: var(--text); }
.keep { white-space: nowrap; }
.grid { display: grid; gap: 24px; }
.grid--two { grid-template-columns: repeat(2,minmax(0,1fr)); }
.grid--three { grid-template-columns: repeat(3,minmax(0,1fr)); }
.grid > *, .win__body > *, .duo > *, .footer-grid > *, .tabs > *, .prose, .prose div { min-width: 0; }
.cluster { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.stack > * + * { margin-top: 24px; }
.icon { width: 20px; height: 20px; flex-shrink: 0; }
.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: fixed;
  left: 16px;
  top: 12px;
  z-index: var(--layer-menu);
  transform: translateY(-180%);
  padding: 12px 20px;
  background: var(--ink);
  color: var(--on-ink);
  border-radius: var(--r-pill);
}
.skip-link:focus { transform: none; }
.topbar { position: relative; z-index: var(--layer-header); border-bottom: 1px solid var(--clear); background: var(--bg); color: var(--text); }
.topbar__in {
  max-width: min(100%,calc(var(--wrap-nav) + var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
  height: var(--header-height);
  display: flex;
  align-items: center;
  gap: 28px;
}
.brand { display: inline-flex; align-items: center; gap: 11px; flex-shrink: 0; }
.brand__mark { display: block; width: 34px; height: 34px; flex-shrink: 0; }
.brand__name { font: var(--weight-heavy) var(--fs-lede)/1.3 var(--font-display); letter-spacing: -.01em; }
.desktop-nav { margin-left: auto; min-width: 0; }
.navlist { display: flex; align-items: center; list-style: none; margin: 0; padding: 0; gap: 2px; }
.navlist a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 14px;
  border-radius: var(--r-pill);
  font-size: var(--fs-nav);
  font-weight: var(--weight-medium);
  color: var(--text-muted);
  white-space: nowrap;
  transition: color var(--speed),background-color var(--speed);
}
.navlist a:hover { background: var(--bg-panel); color: var(--text); }
.navlist a[aria-current="page"] { background: var(--accent-soft); color: var(--accent-dark); font-weight: var(--weight-semibold); }
.header-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.language { position: relative; }
.lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  height: 38px;
  padding-inline: 14px;
  border: 1px solid var(--border);
  border-radius: var(--r-pill);
  background: var(--bg);
  color: var(--text);
  font: var(--weight-medium) var(--fs-ui)/1 var(--font-body);
  white-space: nowrap;
}
.lang svg { width: 15px; height: 15px; color: var(--text-muted); flex-shrink: 0; }
.lang__caret { color: var(--text-muted); font-size: var(--fs-xs); }
.lang__short { display: none; }
.language-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  min-width: 190px;
  margin: 0;
  padding: 8px;
  list-style: none;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-float);
  z-index: var(--layer-menu);
}
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 10px 14px; border-radius: var(--r-sm); }
.language-menu a:hover, .language-menu a[aria-current] { background: var(--accent-soft); color: var(--accent-dark); }
.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: var(--r-pill);
  background: var(--bg);
  color: var(--text);
}
.menu-toggle svg { width: 22px; height: 22px; flex-shrink: 0; }
.nav-veil { position: fixed; inset: var(--header-height) 0 0; z-index: var(--layer-veil); border: 0; background: var(--veil); color: var(--text); }
.mobile-drawer {
  position: absolute;
  top: var(--header-height);
  left: 0;
  right: 0;
  z-index: var(--layer-menu);
  padding: 16px var(--gutter) 24px;
  max-height: calc(100dvh - var(--header-height));
  overflow-y: auto;
  overscroll-behavior: contain;
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
}
.mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
.mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 46px; padding: 11px 16px; border-radius: var(--r-md); }
.mobile-drawer a:hover, .mobile-drawer a[aria-current] { background: var(--accent-soft); color: var(--accent-dark); }
.mobile-drawer__label { margin: 20px 16px 8px; color: var(--text-muted); font-size: var(--fs-small); }
.preview-language { position: relative; }
.preview-language summary { list-style: none; cursor: pointer; }
.preview-language summary::-webkit-details-marker { display: none; }
.actions { display: flex; justify-content: center; gap: 12px; margin-top: 28px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 52px;
  padding: 12px 26px;
  border: 1px solid var(--clear);
  border-radius: var(--r-pill);
  font-size: var(--fs-body);
  font-weight: var(--weight-bold);
  letter-spacing: .005em;
  text-align: center;
  transition: background-color var(--speed),border-color var(--speed),transform var(--speed);
}
.btn svg { width: 18px; height: 18px; flex-shrink: 0; }
.btn--ink { background: var(--ink); color: var(--on-ink); box-shadow: var(--shadow-btn); }
.btn--ink:hover, .btn--ink.is-hover { background: var(--ink-hover); color: var(--on-ink); }
.btn--line { background: var(--bg); color: var(--text); border-color: var(--border-strong); }
.btn--line:hover, .btn--line.is-hover { background: var(--bg-panel); color: var(--text); border-color: var(--text-faint); }
.btn--small { min-height: 44px; padding: 10px 20px; font-size: var(--fs-ui); }
.btn:active, .btn.is-pressed { transform: translateY(1px); }
.btn.is-focus { outline: 2px solid var(--accent); outline-offset: 3px; }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--bg-panel-2); color: var(--text-muted); border-color: var(--border); cursor: not-allowed; box-shadow: none; }
.text-link { color: var(--accent-dark); font-weight: var(--weight-semibold); }
.text-link:hover { text-decoration: underline; text-underline-offset: 4px; }
.card { padding: 28px; border: 1px solid var(--border); border-radius: var(--r-xl); background: var(--bg); color: var(--text); }
.card h3 { margin: 0 0 16px; font-size: var(--fs-card); }
.card p:last-child { margin-bottom: 0; }
.card--panel { background: var(--bg-panel); color: var(--text); }
.dark-panel { padding: 28px; border: 1px solid var(--win-line); border-radius: var(--r-xl); background: var(--win); color: var(--win-text); }
.dark-panel pre { margin: 0; padding: 0; border: 0; background: var(--win); color: var(--win-text); }
.prose { line-height: 1.85; }
.prose h2 { margin-top: 2.5em; margin-bottom: 1em; scroll-margin-top: 28px; }
.prose h3 { margin-top: 1.8em; margin-bottom: .8em; }
.prose a:not(.btn) { color: var(--accent-dark); text-decoration: underline; text-underline-offset: 3px; }
.prose :not(pre) > code { padding: 2px 5px; border-radius: var(--r-xs); background: var(--bg-panel); color: var(--text); font-size: .9em; }
.prose li + li { margin-top: 10px; }
.reveal { opacity: 1; transform: none; }
.reveal.reveal-ready { opacity: 0; transform: translateY(18px); transition: opacity var(--reveal-speed),transform var(--reveal-speed); }
.reveal.shown { opacity: 1; transform: none; }
.site-footer { border-top: 1px solid var(--border); padding-top: 64px; padding-bottom: 28px; background: var(--bg); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: 1.35fr 1fr 1.3fr .75fr; gap: 40px; }
.footer-brand p { max-width: 310px; margin-top: 20px; color: var(--text-muted); font-size: var(--fs-ui); }
.site-footer h2 { font-size: var(--fs-ui); letter-spacing: 0; margin: 4px 0 18px; font-weight: var(--weight-bold); }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links li + li { margin-top: 10px; }
.footer-links a { color: var(--text-muted); font-size: var(--fs-ui); overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--accent-dark); }
.footer-bottom { border-top: 1px solid var(--border); margin-top: 48px; padding-top: 24px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; font-size: var(--fs-small); color: var(--text-muted); }
.footer-bottom p { margin: 0; }
@media (max-width: 1199px) {
  .desktop-nav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
}
@media (min-width: 1200px) {
  .mobile-drawer, .nav-veil { display: none !important; }
}
@media (max-width: 860px) {
  .grid--three { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .footer-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
}
@media (max-width: 768px) {
  :root { --fs-h1: clamp(24px,5vw,30px); }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; --fs-h2: 26px; --fs-h3: 22px; }
  .topbar__in { gap: 10px; }
  .brand { gap: 8px; }
  .brand__name { font-size: var(--fs-ui); }
  .brand__mark { width: 30px; height: 30px; }
  .lang { padding-inline: 10px; min-height: 44px; }
  .lang__full { display: none; }
  .lang__short { display: inline; }
  .header-tools { margin-left: auto; gap: 6px; }
  .section { padding-top: 64px; padding-bottom: 64px; }
  .grid--two, .grid--three { grid-template-columns: minmax(0,1fr); }
  .card, .dark-panel { padding: 22px; }
  .actions { flex-direction: column; align-items: stretch; padding-inline: 8px; }
  .footer-grid { gap: 32px 20px; }
  .footer-brand { grid-column: 1 / -1; }
  .tilt, [data-tilt] { transform: none !important; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal.reveal-ready { opacity: 1; transform: none; }
}