:root {
  --bg: #FFFFFF;
  --bg-panel: #F4F5F7;
  --bg-panel-2: #EBEDF0;
  --border: #E3E5E8;
  --border-strong: #D5D8DC;
  --accent: #2B9FD9;
  --accent-dark: #1676AD;
  --accent-soft: #E8F4FB;
  --accent-line: #BFE0F2;
  --text: #2F3439;
  --text-muted: #6B7178;
  --text-faint: #A0A5AB;
  --on-accent: #FFFFFF;
  --success: #2E9E62;
  --warn: #C98A12;
  --error: #D64545;
  --clear: transparent;
  --veil: rgba(47, 52, 57, .22);
  --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;
  --weight-normal: 400;
  --weight-medium: 600;
  --weight-bold: 700;
  --weight-display: 800;
  --size-xs: 12px;
  --size-sm: 13px;
  --size-nav: 15px;
  --size-body: 16px;
  --size-lede: 17px;
  --size-h1: clamp(34px, 3.4vw, 48px);
  --size-h2: 32px;
  --size-h3: 22px;
  --size-mobile-h1: 28px;
  --size-mobile-h2: 24px;
  --size-device-tiny: 8.5px;
  --size-device-small: 10px;
  --size-device-rule: 10.5px;
  --size-device-body: 11px;
  --r-xs: 4px;
  --r-sm: 6px;
  --r-md: 8px;
  --r-lid: 16px;
  --r-phone: 30px;
  --r-screen: 24px;
  --r-pill: 999px;
  --r-round: 50%;
  --shadow-card: 0 1px 2px rgba(47,52,57,.05);
  --shadow-btn: 0 1px 2px rgba(22,118,173,.18), 0 6px 16px -8px rgba(22,118,173,.45);
  --shadow-window: 0 1px 2px rgba(47,52,57,.06), 0 12px 28px -14px rgba(47,52,57,.22);
  --shadow-laptop: 0 46px 90px -40px rgba(47,52,57,.30);
  --shadow-base: 0 10px 18px -12px rgba(47,52,57,.28);
  --shadow-phone: 0 1px 3px rgba(47,52,57,.08), 0 22px 40px -18px rgba(47,52,57,.34), 0 60px 90px -40px rgba(47,52,57,.34);
  --shadow-knob: 0 1px 2px rgba(47,52,57,.25);
  --nav-h: 64px;
  --peek: 44px;
  --wrap: 1336px;
  --reading: 800px;
  --gutter: 48px;
  --section-space: 96px;
  --ease: cubic-bezier(.22,.61,.36,1);
  --fast: .2s;
  --reveal-time: .6s;
  --cycle: 18s;
  --feature-time: 8s;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 24px); }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--size-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
img, svg, video { max-width: 100%; vertical-align: middle; }
img { height: auto; }
svg, .pill-dot, .brand-mark { flex-shrink: 0; }
button, input, textarea, select { font: inherit; color: inherit; }
button, a { -webkit-tap-highlight-color: var(--clear); }
button { cursor: pointer; }
a { color: var(--accent-dark); text-underline-offset: .2em; }
a:hover { text-decoration-thickness: 2px; }
button:disabled { cursor: not-allowed; }
:focus-visible { outline: 2px solid var(--accent-dark); outline-offset: 3px; border-radius: var(--r-xs); }
h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.25; text-wrap: balance; }
h1, .h1 { font-size: var(--size-h1); font-weight: var(--weight-display); line-height: 1.14; letter-spacing: -.02em; }
h2 { font-size: var(--size-h2); font-weight: var(--weight-display); letter-spacing: -.02em; }
h3 { font-size: var(--size-h3); font-weight: var(--weight-bold); }
p { margin: 0 0 1em; }
h1, h2, h3 { margin: 0 0 .65em; }
ul, ol { padding-inline-start: 1.4em; }
code, pre, .mono { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; font-size: .9em; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--bg-panel);
  color: var(--text);
  font-size: var(--size-sm);
  line-height: 1.8;
}
pre code { overflow-wrap: normal; word-break: normal; white-space: pre; font-size: inherit; }
:where(main, section, article, aside, nav, div, li) { min-width: 0; }
.wrap, .dl-wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.reading { max-width: calc(var(--reading) + var(--gutter) * 2); }
.section { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.panel-section { background: var(--bg-panel); color: var(--text); }
.decorated, .hero { overflow-x: clip; }
.nowrap { white-space: nowrap; }
.muted, .eyebrow { color: var(--text-muted); }
.eyebrow { font-size: var(--size-sm); letter-spacing: .04em; }
.lede { max-width: 36em; color: var(--text-muted); font-size: var(--size-lede); line-height: 1.75; }
.lede strong { color: var(--text); font-weight: var(--weight-medium); }
.prose { line-height: 1.85; overflow-wrap: break-word; }
.prose h2 { margin-top: 2.4em; }
.prose h3 { margin-top: 1.8em; }
.prose li + li { margin-top: .5em; }
.prose :where(h2, h3, h4, [id]) { scroll-margin-top: calc(var(--nav-h) + 28px); }
.prose :not(pre) > code {
  padding: .12em .3em;
  background: var(--bg-panel);
  color: var(--text);
  border-radius: var(--r-xs);
}
.grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.grid > *, .hero-grid > * { min-width: 0; }
.card, .panel {
  padding: 28px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-card);
}
.panel { background: var(--bg-panel); color: var(--text); }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.cta, .button-row { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 10px 22px;
  border: 1px solid var(--clear);
  border-radius: var(--r-md);
  background: var(--bg);
  color: var(--text);
  font-size: var(--size-nav);
  font-weight: var(--weight-medium);
  line-height: 1.4;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--fast) var(--ease), border-color var(--fast) var(--ease), color var(--fast) var(--ease);
}
.btn svg { width: 16px; height: 16px; }
.btn-primary { background: var(--accent); color: var(--on-accent); box-shadow: var(--shadow-btn); }
.btn-primary:hover, .btn-primary.is-hover { background: var(--accent-dark); color: var(--on-accent); }
.btn-primary:active { transform: translateY(1px); }
.btn-ghost { background: var(--bg); color: var(--text); border-color: var(--border); }
.btn-ghost:hover { color: var(--accent-dark); border-color: var(--accent-line); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--bg-panel); color: var(--text-muted); border-color: var(--border); box-shadow: none; }
.btn.is-focus { outline: 2px solid var(--accent-dark); outline-offset: 3px; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--nav-h);
  background: var(--bg);
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  position: relative;
  max-width: min(100%, calc(1280px + var(--gutter) * 2));
  height: 100%;
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 20px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  color: var(--text);
  font-family: var(--font-display);
  font-size: var(--size-body);
  font-weight: var(--weight-bold);
  text-decoration: none;
}
.brand-mark { width: 30px; height: 30px; }
.nav { height: 100%; min-width: 0; margin-left: auto; }
.tabs {
  display: flex;
  align-items: center;
  list-style: none;
  height: 100%;
  gap: 2px;
  margin: 0;
  padding: 0;
}
.tabs li { height: 100%; }
.tab {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  padding: 0 16px;
  white-space: nowrap;
  color: var(--text-muted);
  font-size: var(--size-nav);
  text-decoration: none;
  transition: color var(--fast) var(--ease);
}
.tab:hover, .tab[aria-current="page"] { color: var(--text); }
.tab[aria-current="page"] { font-weight: var(--weight-medium); }
.tab[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: -1px;
  height: 2px;
  border-radius: var(--r-xs);
  background: var(--accent);
  color: var(--text);
}
.header-tools { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.language { position: relative; }
.lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  padding: 6px 0 6px 20px;
  border: 0;
  border-left: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font-size: var(--size-sm);
  white-space: nowrap;
  list-style: none;
}
.lang svg { width: 15px; height: 15px; }
.lang-short { display: none; }
.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 190px;
  padding: 6px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-window);
}
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 8px 12px; color: var(--text); text-decoration: none; }
.language-menu a:hover, .language-menu a[aria-current="true"] { background: var(--bg-panel); 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-md);
  background: var(--bg);
  color: var(--text);
}
.menu-toggle svg { width: 20px; height: 20px; }
.mobile-drawer {
  position: absolute;
  top: var(--nav-h);
  left: 0;
  right: 0;
  z-index: 3;
  max-height: calc(100dvh - var(--nav-h));
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 16px var(--gutter) 24px;
  background: var(--bg);
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 48px; padding: 12px; color: var(--text); text-decoration: none; }
.mobile-drawer a[aria-current] { color: var(--accent-dark); font-weight: var(--weight-medium); }
.drawer-languages { border-top: 1px solid var(--border); margin-top: 12px; padding-top: 12px; }
.menu-veil { position: fixed; inset: var(--nav-h) 0 0; z-index: 1; border: 0; background: var(--veil); color: var(--text); }
.mobile-drawer, .header-tools, .brand, .nav { z-index: 2; }
.preview-mobile { display: none; }
.site-footer { background: var(--bg-panel); color: var(--text); border-top: 1px solid var(--border); }
.footer-grid { display: grid; grid-template-columns: 1.4fr .8fr 1.4fr .7fr; gap: 40px; padding-top: 64px; padding-bottom: 48px; }
.footer-grid h2 { font-size: var(--size-sm); font-weight: var(--weight-bold); letter-spacing: 0; margin-bottom: 18px; }
.footer-grid p { max-width: 25em; margin-top: 18px; color: var(--text-muted); font-size: var(--size-sm); line-height: 1.85; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li + li { margin-top: 10px; }
.footer-grid a:not(.brand), .footer-bottom a { color: var(--text-muted); font-size: var(--size-sm); text-decoration: none; }
.footer-grid a:hover, .footer-bottom a:hover { color: var(--accent-dark); }
.footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; border-top: 1px solid var(--border); padding-top: 20px; padding-bottom: 24px; font-size: var(--size-xs); color: var(--text-muted); }
.reveal { opacity: 1; transform: none; }
html.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(18px); }
html.reveal-ready .reveal { transition: opacity var(--reveal-time) var(--ease), transform var(--reveal-time) var(--ease); }
.reveal.shown { opacity: 1; transform: none; }
@media (max-width: 1100px) {
  .nav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .preview-mobile { display: block; }
  .preview-mobile > summary { display: inline-flex; }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 1000px) {
  :root { --gutter: 28px; --section-space: 72px; }
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  h1, .h1 { font-size: var(--size-mobile-h1); }
  h2 { font-size: var(--size-mobile-h2); }
}
@media (max-width: 640px) {
  :root { --gutter: 20px; --section-space: 56px; }
  .grid, .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { gap: 30px; padding-top: 44px; }
  .header-inner { gap: 8px; }
  .header-tools { margin-left: auto; gap: 4px; }
  .lang { border-left: 0; padding-left: 8px; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .card, .panel { padding: 22px; }
  .tilt, [data-tilt] { transform: none !important; }
}
@media (max-width: 360px) {
  :root { --gutter: 16px; }
  .brand { font-size: var(--size-sm); gap: 7px; }
  .header-tools { gap: 2px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  html.reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}