:root {
  --bg: #F0F2F1;
  --bg-panel: #FFFFFF;
  --bg-panel-2: #E6E9E8;
  --border: #D9DDDC;
  --accent: #0E52E6;
  --accent-dark: #0A3BB0;
  --wine: #6E1A3A;
  --text: #15191A;
  --text-muted: #5B6463;
  --success: #1F9D61;
  --warn: #C98A12;
  --error: #C7362F;
  --on-accent: #FFFFFF;
  --clear: transparent;
  --accent-a00: rgba(14, 82, 230, 0);
  --accent-a05: rgba(14, 82, 230, 0.05);
  --accent-a08: rgba(14, 82, 230, 0.08);
  --accent-a12: rgba(14, 82, 230, 0.12);
  --accent-a16: rgba(14, 82, 230, 0.16);
  --accent-a24: rgba(14, 82, 230, 0.24);
  --accent-a36: rgba(14, 82, 230, 0.36);
  --white-a55: rgba(255, 255, 255, 0.55);
  --white-a80: rgba(255, 255, 255, 0.8);
  --ink-a05: rgba(21, 25, 26, 0.05);
  --ink-a08: rgba(21, 25, 26, 0.08);
  --ink-a14: rgba(21, 25, 26, 0.14);
  --ink-a36: rgba(21, 25, 26, 0.36);
  --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;
  --weight-regular: 400;
  --weight-medium: 500;
  --weight-strong: 600;
  --r-ctl: 6px;
  --r-card: 10px;
  --r-hero: 14px;
  --r-pill: 999px;
  --r-round: 50%;
  --r-mark: 2px;
  --shadow-card: 0 1px 2px var(--ink-a05), 0 16px 34px -14px var(--ink-a14);
  --shadow-float: 0 1px 2px var(--ink-a08), 0 22px 40px -18px var(--ink-a14);
  --shadow-btn: 0 1px 2px var(--ink-a08), 0 10px 22px -10px var(--accent-a36);
  --nav-h: 72px;
  --gutter: clamp(16px, 5vw, 72px);
  --inset: clamp(24px, 4.5vw, 64px);
  --read-width: 1120px;
  --nav-width: 1280px;
  --space-section: clamp(56px, 7vw, 104px);
  --ease-out: cubic-bezier(0.2, 0.7, 0.2, 1);
  --duration-fast: 0.18s;
  --duration-reveal: 0.6s;
}
*, *::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-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
main, section, article, aside, nav, div, li { min-width: 0; }
img, svg, video { max-width: 100%; }
img { height: auto; }
svg { flex-shrink: 0; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button, summary { -webkit-tap-highlight-color: var(--accent-a12); }
button:disabled { cursor: not-allowed; }
a:focus-visible, button:focus-visible, summary:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--r-ctl);
}
[hidden] { display: none !important; }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-regular);
  letter-spacing: -0.02em;
  text-wrap: balance;
  overflow-wrap: normal;
}
h1 { font-size: clamp(34px, 3.4vw, 48px); line-height: 1.12; }
h2 { font-size: clamp(26px, 2.6vw, 36px); line-height: 1.25; }
h3 { font-size: 22px; line-height: 1.35; }
p { margin-top: 0; }
strong { font-weight: var(--weight-strong); }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; font-size: 0.88em; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  background: var(--bg-panel-2);
  color: var(--text);
  line-height: 1.7;
}
pre code { 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(--read-width) + var(--gutter) * 2);
  padding-inline: var(--gutter);
  margin-inline: auto;
}
.section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.section-band { background: var(--bg-panel-2); color: var(--text); }
.decorated, .hero, .grid-stage { overflow-x: clip; }
.nowrap { white-space: nowrap; }
.muted { color: var(--text-muted); }
.mono { font-family: var(--font-mono); }
.text-link, .prose a { color: var(--accent); text-decoration: underline; text-underline-offset: 4px; }
.text-link:hover, .prose a:hover { color: var(--accent-dark); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.prose { max-width: 76ch; }
.prose p, .prose li { line-height: 1.9; }
.prose h2 { margin-top: 2em; scroll-margin-top: 24px; }
.prose h3 { margin-top: 1.7em; }
.prose img { display: block; }
.prose blockquote { margin-inline: 0; }
.card, .panel {
  padding: 28px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  box-shadow: var(--shadow-card);
}
.panel-soft { background: var(--bg-panel-2); color: var(--text); }
.card h3, .panel h3 { margin-top: 0; }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.cta-row { margin-top: 32px; display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 52px;
  padding: 10px 28px;
  border: 1px solid var(--clear);
  border-radius: var(--r-pill);
  font-size: 16px;
  font-weight: var(--weight-medium);
  line-height: 1.4;
  text-align: center;
  transition: background-color var(--duration-fast) ease, color var(--duration-fast) ease, border-color var(--duration-fast) ease, transform var(--duration-fast) ease;
}
.btn svg { width: 18px; height: 18px; }
.btn svg path { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.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); transform: translateY(-1px); }
.btn-ghost { border-color: var(--accent); color: var(--accent); background: var(--accent-a00); }
.btn-ghost:hover, .btn-ghost.is-hover { background: var(--accent-a05); color: var(--accent-dark); border-color: var(--accent-dark); }
.btn:active, .btn.is-active { transform: translateY(1px); box-shadow: none; }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--bg-panel-2); color: var(--text-muted); border-color: var(--border); box-shadow: none; transform: none; }
.btn.is-focus { outline: 2px solid var(--accent); outline-offset: 3px; }
.btn-small { min-height: 44px; padding: 8px 20px; font-size: 14px; }
.topbar {
  height: var(--nav-h);
  width: 100%;
  max-width: min(100%, calc(var(--nav-width) + var(--gutter) * 2));
  padding-inline: var(--gutter);
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: 40px;
  position: relative;
  z-index: 60;
}
#site-header { position: relative; z-index: 60; }
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: var(--weight-medium);
  letter-spacing: -0.01em;
  color: var(--text);
  flex-shrink: 0;
}
.brand-mark { width: 30px; height: 30px; display: block; flex-shrink: 0; }
.mainnav { flex: 1; min-width: 0; display: flex; justify-content: center; }
.mainnav-list { display: flex; align-items: center; list-style: none; margin: 0; padding: 0; gap: 6px; }
.mainnav-link, .nav-more > summary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 40px;
  padding: 0 14px;
  border-radius: var(--r-ctl);
  font-size: 15px;
  white-space: nowrap;
  color: var(--text-muted);
  cursor: pointer;
  transition: color var(--duration-fast) ease, background-color var(--duration-fast) ease;
}
.mainnav-link:hover, .nav-more > summary:hover { color: var(--text); background: var(--white-a55); }
.mainnav-link[aria-current="page"], .nav-more.is-current > summary { color: var(--text); }
.mainnav-link[aria-current="page"]::before {
  content: "";
  width: 5px;
  height: 5px;
  flex-shrink: 0;
  border-radius: var(--r-round);
  background: var(--accent);
}
.nav-more, .lang-switch { position: relative; }
summary { cursor: pointer; }
.nav-more > summary, .lang-switch > summary, .static-mobile > summary { list-style: none; }
.nav-more > summary::-webkit-details-marker, .lang-switch > summary::-webkit-details-marker, .static-mobile > summary::-webkit-details-marker { display: none; }
.chev { width: 12px; height: 12px; transition: transform var(--duration-fast) ease; }
.chev path { fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
details[open] > summary .chev { transform: rotate(180deg); }
.dropdown {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  min-width: 232px;
  max-width: calc(100vw - 32px);
  padding: 6px;
  margin: 0;
  list-style: none;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  box-shadow: var(--shadow-float);
  z-index: 4;
}
.dropdown a { display: block; min-height: 44px; padding: 10px 12px; border-radius: var(--r-ctl); }
.dropdown a:hover, .dropdown a[aria-current="page"] { background: var(--bg); color: var(--text); }
.dd-title { display: block; font-size: 14px; color: var(--text); }
.dd-note { display: block; font-size: 12.5px; color: var(--text-muted); line-height: 1.45; white-space: normal; }
.topbar-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; margin-left: auto; }
.lang-switch > summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 40px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: var(--r-pill);
  background: var(--bg-panel);
  color: var(--text);
  font-size: 14px;
  white-space: nowrap;
}
.lang-switch > summary:hover { border-color: var(--accent-a36); }
.globe { width: 16px; height: 16px; }
.globe circle, .globe path { fill: none; stroke: currentColor; stroke-width: 1.3; }
.lang-switch .dropdown { left: auto; right: 0; min-width: 160px; }
.lang-switch .dropdown a { font-size: 14px; }
.lang-short { display: none; }
.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-ctl);
  background: var(--bg-panel);
  color: var(--text);
}
.menu-toggle svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.6; }
.mobile-drawer {
  position: absolute;
  top: var(--nav-h);
  left: var(--gutter);
  right: var(--gutter);
  padding: 16px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  box-shadow: var(--shadow-float);
  max-height: calc(100dvh - var(--nav-h) - 16px);
  overflow-y: auto;
  overscroll-behavior: contain;
  z-index: 5;
}
.mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
.mobile-drawer a { display: flex; width: 100%; align-items: center; min-height: 44px; padding: 10px 12px; border-radius: var(--r-ctl); }
.mobile-drawer a:hover, .mobile-drawer a[aria-current="page"] { background: var(--bg); color: var(--accent-dark); }
.drawer-label { margin: 16px 12px 6px; padding-top: 16px; border-top: 1px solid var(--border); font-size: 13px; color: var(--text-muted); }
.nav-veil { position: fixed; inset: var(--nav-h) 0 0; z-index: 50; border: 0; background: var(--ink-a36); color: var(--text); }
.static-mobile { display: none; }
.site-footer { margin-top: 40px; padding-top: 64px; padding-bottom: 96px; border-top: 1px solid var(--border); background: var(--bg-panel-2); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: 1.25fr 0.8fr 1.4fr 0.7fr; gap: 40px; }
.footer-brand p { max-width: 28em; margin-top: 20px; font-size: 14px; color: var(--text-muted); }
.footer-title { margin: 0 0 16px; font-size: 15px; font-weight: var(--weight-medium); }
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links a { display: inline-block; padding-block: 5px; font-size: 14px; color: var(--text-muted); }
.footer-links a:hover { color: var(--accent-dark); text-decoration: underline; text-underline-offset: 3px; }
.footer-bottom { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 16px; margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--border); font-size: 13px; color: var(--text-muted); }
.footer-bottom p { margin: 0; }
.footer-legal { display: flex; flex-wrap: wrap; gap: 20px; }
.reveal { opacity: 1; transform: none; }
.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(18px); }
.reveal-ready .reveal { transition: opacity var(--duration-reveal) var(--ease-out), transform var(--duration-reveal) var(--ease-out); }
.reveal.shown { opacity: 1; transform: none; }
@media (max-width: 1100px) {
  .topbar { gap: 20px; }
  .mainnav { display: none; }
  .topbar-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .static-mobile { display: block; }
  .static-mobile .mobile-drawer { z-index: 5; }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 1101px) {
  .mobile-drawer, .nav-veil { display: none !important; }
}
@media (max-width: 768px) {
  h1 { font-size: clamp(24px, 4vw, 30px); }
  .card-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .topbar { gap: 8px; }
  .brand { font-size: 16px; gap: 7px; }
  .brand-mark { width: 26px; height: 26px; }
  .topbar-tools { gap: 6px; margin-left: auto; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang-switch > summary { padding-inline: 10px; gap: 5px; }
  .card, .panel { padding: 20px; }
  .tilt, [data-tilt] { transform: none !important; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .btn { min-height: 48px; padding-inline: 22px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}