:root {
  --bg: #FFFFFF;
  --bg-panel: #F5F6F8;
  --bg-panel-2: #EDEFF3;
  --border: #E3E6EB;
  --neutral-300: #D3D7DE;
  --accent: #1A54D6;
  --accent-dark: #0F3A9E;
  --accent-2: #8F4BE8;
  --accent-tint: rgba(26, 84, 214, 0.07);
  --text: #16181D;
  --text-muted: #5B616E;
  --text-faint: #8C929E;
  --on-accent: #FFFFFF;
  --success: #1F8A4C;
  --warn: #B86E00;
  --error: #D13B3B;
  --clear: transparent;
  --veil: rgba(22, 24, 29, 0.24);
  --font-display: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans', 'Malgun Gothic', 'Microsoft YaHei', system-ui, sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans', 'Apple SD Gothic Neo', 'Malgun Gothic', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', Menlo, Consolas, 'Noto Sans SC', monospace;
  --weight-body: 400;
  --weight-medium: 500;
  --weight-strong: 600;
  --weight-brand: 800;
  --weight-display: 900;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lead: 1.0625rem;
  --text-h1: clamp(34px, 2.2vw + 16px, 48px);
  --text-h2: clamp(28px, 3vw, 40px);
  --text-h3: clamp(20px, 2vw, 26px);
  --leading-body: 1.65;
  --leading-display: 1.12;
  --tracking-display: -0.015em;
  --radius-pill: 999px;
  --radius-round: 50%;
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 16px;
  --radius-sm: 12px;
  --radius-xs: 6px;
  --radius-mark: 9px;
  --radius-index: 4px;
  --shadow-device: 0 1px 2px rgba(22, 24, 29, 0.04), 0 12px 28px -14px rgba(22, 24, 29, 0.10), 0 40px 90px -36px rgba(22, 24, 29, 0.20);
  --shadow-float: 0 2px 6px rgba(22, 24, 29, 0.06), 0 24px 48px -16px rgba(22, 24, 29, 0.30);
  --shadow-cta: 0 10px 22px -10px rgba(26, 84, 214, 0.55);
  --shadow-card: 0 2px 4px rgba(22, 24, 29, 0.03), 0 18px 46px -26px rgba(22, 24, 29, 0.18);
  --gutter: 24px;
  --content-width: 1128px;
  --reading-width: 800px;
  --nav-width: 1280px;
  --nav-h: 68px;
  --section-space: clamp(64px, 8vw, 120px);
  --ease: cubic-bezier(.2, .7, .2, 1);
  --speed-fast: 150ms;
  --speed-ui: 180ms;
  --speed-reveal: 600ms;
  --focus-ring: 2px solid var(--accent);
}
*, *::before, *::after { box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
  background: var(--bg);
  color: var(--text);
}
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
[hidden] { display: none !important; }
img, svg { max-width: 100%; vertical-align: middle; }
img { height: auto; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
a { color: var(--accent); text-underline-offset: 0.2em; }
a:hover { color: var(--accent-dark); }
:focus-visible { outline: var(--focus-ring); outline-offset: 3px; }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--text);
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1, h2 {
  font-weight: var(--weight-display);
  line-height: var(--leading-display);
  letter-spacing: var(--tracking-display);
}
h1 { font-size: var(--text-h1); margin: 0 0 24px; }
h2 { font-size: var(--text-h2); margin: 0 0 24px; }
h3 { font-size: var(--text-h3); font-weight: var(--weight-brand); line-height: 1.3; margin: 0 0 16px; }
p { margin: 0 0 20px; }
ul, ol { padding-inline-start: 1.5em; }
li + li { margin-top: 0.35em; }
code, pre, kbd, samp { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; font-size: 0.92em; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--bg-panel);
  color: var(--text);
  font-size: var(--text-sm);
  line-height: 1.75;
  tab-size: 2;
}
pre code { font-size: inherit; overflow-wrap: normal; word-break: normal; white-space: pre; }
hr { border: 0; border-top: 1px solid var(--border); margin-block: 32px; }
.wrap {
  width: 100%;
  max-width: calc(var(--content-width) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.reading { max-width: calc(var(--reading-width) + var(--gutter) * 2); }
.section { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.section--panel { background: var(--bg-panel); color: var(--text); }
.section-heading { max-width: 760px; margin: 0 auto 40px; text-align: center; }
.lead { font-size: var(--text-lead); color: var(--text-muted); }
.muted { color: var(--text-muted); }
.mono { font-family: var(--font-mono); }
.keep { white-space: nowrap; }
.grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.grid--three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid > *, .wrap > *, .card > *, .panel > *, .prose > * { min-width: 0; }
.stack > * + * { margin-top: 24px; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 16px; }
.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: absolute;
  left: var(--gutter);
  top: -100px;
  z-index: 100;
  padding: 12px 20px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  color: var(--on-accent);
}
.skip-link:focus { top: 8px; color: var(--on-accent); }
.btn, .btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 52px;
  max-width: 100%;
  padding: 12px 30px;
  border: 1px solid var(--clear);
  border-radius: var(--radius-pill);
  background: var(--accent);
  color: var(--on-accent);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-strong);
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  box-shadow: var(--shadow-cta);
  transition: background-color var(--speed-ui) var(--ease), transform var(--speed-ui) var(--ease);
}
.btn svg, .btn-primary svg { width: 18px; height: 18px; flex-shrink: 0; }
.btn:hover, .btn-primary:hover, .btn.is-hover {
  background: var(--accent-dark);
  color: var(--on-accent);
  transform: translateY(-1px);
}
.btn:active, .btn-primary:active, .btn.is-active { transform: translateY(1px); }
.btn--secondary {
  background: var(--bg);
  color: var(--text);
  border-color: var(--border);
  box-shadow: none;
}
.btn--secondary:hover { background: var(--bg-panel-2); color: var(--text); }
.btn--quiet { background: var(--bg-panel); color: var(--text); box-shadow: none; }
.btn--quiet:hover { background: var(--bg-panel-2); color: var(--text); }
.btn:disabled, .btn[aria-disabled="true"] {
  background: var(--bg-panel-2);
  color: var(--text-muted);
  border-color: var(--border);
  box-shadow: none;
  cursor: not-allowed;
  transform: none;
}
.btn.is-focus { outline: var(--focus-ring); outline-offset: 3px; }
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent);
  font-size: var(--text-base);
  font-weight: var(--weight-strong);
  text-decoration: none;
}
.link-arrow__mark { transition: transform var(--speed-ui) var(--ease); }
.link-arrow:hover .link-arrow__mark { transform: translateX(3px); }
.card, .panel {
  padding: 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-card);
}
.panel { border-radius: var(--radius-xl); background: var(--bg-panel); color: var(--text); }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.card__head { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; margin-bottom: 16px; }
.card__head h3 { margin: 0; }
.prose { min-width: 0; line-height: 1.85; }
.prose h2 { margin-top: 64px; scroll-margin-top: 24px; }
.prose h3 { margin-top: 32px; scroll-margin-top: 24px; }
.prose li { margin-bottom: 8px; }
.prose img { border-radius: var(--radius-md); }
.prose :not(pre) > code {
  padding: 0.1em 0.3em;
  border-radius: var(--radius-index);
  background: var(--bg-panel);
  color: var(--text);
}
.topbar { position: relative; z-index: 30; height: var(--nav-h); background: var(--bg); color: var(--text); }
.topbar__inner {
  position: relative;
  max-width: min(100%, calc(var(--nav-width) + var(--gutter) * 2));
  height: 100%;
  margin: 0 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);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: var(--weight-brand);
  font-size: 18px;
  letter-spacing: var(--tracking-display);
  white-space: nowrap;
}
.brand:hover { color: var(--text); }
.brand__mark { width: 32px; height: 32px; flex-shrink: 0; border-radius: var(--radius-mark); }
.mainnav { margin-left: auto; min-width: 0; }
.mainnav ul {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 2px;
}
.mainnav li { margin: 0; }
.mainnav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 38px;
  padding: 8px 13px;
  border-radius: var(--radius-pill);
  color: var(--text);
  font-size: 14.5px;
  font-weight: var(--weight-medium);
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--speed-fast) var(--ease), color var(--speed-fast) var(--ease);
}
.mainnav a:hover { background: var(--bg-panel); color: var(--text); }
.ico { width: 16px; height: 16px; flex-shrink: 0; color: var(--text-muted); }
.mainnav a[aria-current="page"], .mobile-drawer a[aria-current="page"] {
  color: var(--accent);
  background: var(--accent-tint);
}
.mainnav a[aria-current="page"] .ico { color: var(--accent); }
.topbar__end { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.topbar__sep { width: 1px; height: 22px; background: var(--border); flex-shrink: 0; }
.language { position: relative; }
.lang, .menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 38px;
  padding: 7px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  background: var(--bg);
  color: var(--text);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  white-space: nowrap;
  text-decoration: none;
}
.lang:hover, .menu-toggle:hover { background: var(--bg-panel); color: var(--text); }
.lang__caret { color: var(--text-muted); font-size: 11px; }
.lang__short { display: none; }
.language__list {
  position: absolute;
  right: 0;
  top: calc(100% + 10px);
  z-index: 45;
  width: 190px;
  margin: 0;
  padding: 8px;
  list-style: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-card);
}
.language__list li { margin: 0; }
.language__list a { display: flex; align-items: center; min-height: 44px; padding: 10px 14px; border-radius: var(--radius-xs); color: var(--text); text-decoration: none; }
.language__list a:hover, .language__list a[aria-current="true"] { background: var(--bg-panel); color: var(--accent); }
.menu-toggle { display: none; min-width: 44px; min-height: 44px; padding: 10px; }
.menu-toggle svg { width: 21px; height: 21px; flex-shrink: 0; }
.mobile-drawer { display: none; }
.nav-veil { position: fixed; inset: var(--nav-h) 0 0; z-index: 20; border: 0; background: var(--veil); color: var(--text); }
.preview-language > summary { list-style: none; }
.preview-language > summary::-webkit-details-marker { display: none; }
.preview-menu { display: none; }
.site-footer { background: var(--bg-panel); color: var(--text); padding-top: 64px; padding-bottom: 28px; }
.footer-grid { display: grid; grid-template-columns: 1.3fr 1fr 1.3fr 0.9fr; gap: 36px; }
.footer-grid > * { min-width: 0; }
.footer-brand p { margin-top: 18px; color: var(--text-muted); font-size: var(--text-sm); max-width: 290px; }
.footer-heading { font-size: var(--text-sm); margin: 0 0 18px; font-weight: var(--weight-strong); }
.footer-links { margin: 0; padding: 0; list-style: none; }
.footer-links li { margin: 0 0 8px; }
.footer-links a { display: inline-block; padding-block: 3px; color: var(--text-muted); font-size: var(--text-sm); text-decoration: none; overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--accent); text-decoration: underline; }
.footer-links a[aria-current="true"] { color: var(--accent); }
.footer-bottom { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 16px; margin-top: 44px; padding-top: 24px; border-top: 1px solid var(--border); color: var(--text-muted); font-size: var(--text-sm); }
.footer-bottom p { margin: 0; }
.footer-bottom a { color: var(--text-muted); }
.reveal { opacity: 1; transform: none; }
.reveal.is-pending { opacity: 0; transform: translateY(14px); }
.reveal.shown { opacity: 1; transform: none; transition: opacity var(--speed-reveal) var(--ease), transform var(--speed-reveal) var(--ease); }
@media (max-width: 1200px) {
  .mainnav { display: none; }
  .topbar__end { margin-left: auto; }
  .topbar__sep { display: none; }
  .menu-toggle { display: inline-flex; }
  .mobile-drawer:not([hidden]) {
    display: block;
    position: absolute;
    top: 100%;
    inset-inline: 0;
    z-index: 40;
    max-height: calc(100dvh - var(--nav-h));
    overflow-y: auto;
    overscroll-behavior: contain;
    padding: 16px var(--gutter) 24px;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    background: var(--bg);
    color: var(--text);
    box-shadow: var(--shadow-card);
  }
  .mobile-drawer ul { padding: 0; margin: 0; list-style: none; }
  .mobile-drawer li { margin: 0; }
  .mobile-drawer a { display: flex; align-items: center; gap: 12px; width: 100%; min-height: 46px; padding: 11px 14px; border-radius: var(--radius-xs); color: var(--text); text-decoration: none; }
  .mobile-drawer a:hover { background: var(--bg-panel); color: var(--accent); }
  .mobile-drawer__title { margin: 16px 14px 6px; color: var(--text-muted); font-size: var(--text-sm); }
  .preview-menu { display: block; }
  .preview-menu > summary { list-style: none; display: inline-flex; }
  .preview-menu > summary::-webkit-details-marker { display: none; }
  .preview-menu .mobile-drawer { top: var(--nav-h); }
}
@media (max-width: 800px) {
  .grid--three { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  h1 { font-size: clamp(24px, 4vw, 30px); }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  .grid, .grid--three { grid-template-columns: minmax(0, 1fr); }
  .card, .panel { padding: 22px; }
  .brand { font-size: 15px; gap: 8px; }
  .topbar__inner { gap: 10px; }
  .topbar__end { gap: 8px; margin-left: auto; }
  .lang { padding-inline: 11px; }
  .lang__full { display: none; }
  .lang__short { display: inline; }
  .lang .ico { display: none; }
  .tilt, .cmd--right, [data-tilt] { transform: none; }
  .footer-grid { gap: 28px 20px; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-bottom { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal.is-pending { opacity: 1; transform: none; }
}