:root {
  --bg: #FFFFFF;
  --panel: #F6F6F4;
  --panel-2: #EDEDEA;
  --line: #E5E5E2;
  --grid: #E9E9E6;
  --accent: #1C6ED3;
  --accent-dark: #0E4FA3;
  --accent-soft: #E4EEFB;
  --accent-ring: #BCD4F3;
  --ink: #191918;
  --ink-2: #3A3A38;
  --muted: #6B6B68;
  --faint: #9A9A96;
  --success: #2E9E62;
  --success-soft: #DCF0E4;
  --warn: #D9901A;
  --error: #D6453B;
  --violet: #7C5CD6;
  --st-blue: #6FA9EE;
  --st-orange: #F0A04B;
  --st-yellow: #F5CB4C;
  --st-purple: #A98CEB;
  --st-green: #62BE8C;
  --clear: transparent;
  --veil: rgba(25, 25, 24, .28);
  --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;
  --r-container: 28px;
  --r-window: 24px;
  --r-card: 20px;
  --r-col: 16px;
  --r-inner: 12px;
  --r-field: 10px;
  --r-pill: 999px;
  --r-circle: 50%;
  --shadow-card: 0 1px 2px rgba(25,25,24,.05), 0 4px 12px -6px rgba(25,25,24,.10);
  --shadow-soft: 0 1px 2px rgba(25,25,24,.04), 0 14px 34px -14px rgba(25,25,24,.14);
  --shadow-plate: 0 40px 90px -40px rgba(25,25,24,.18);
  --shadow-window: 0 2px 0 0 var(--panel-2), 0 2px 6px rgba(25,25,24,.04), 0 28px 56px -22px rgba(25,25,24,.18), 0 70px 130px -50px rgba(25,25,24,.16);
  --shadow-fab: 0 2px 4px rgba(25,25,24,.06), 0 16px 36px -14px rgba(25,25,24,.22);
  --gutter: 24px;
  --content-width: 1200px;
  --reading-width: 800px;
  --header-height: 72px;
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 650;
  --weight-bold: 700;
  --weight-display: 800;
  --text-sm: 14px;
  --text-base: 16px;
  --text-lead: 20px;
  --title-size: clamp(34px, 3.4vw, 48px);
  --tracking-title: -.02em;
  --ease: 180ms ease;
  --section-gap: 96px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 24px; }
html, body { margin: 0; }
html.nav-open { overflow: hidden; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-normal);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
button, summary { cursor: pointer; }
button { border: 0; }
img, svg { vertical-align: middle; }
img { max-width: 100%; height: auto; }
svg, .ico, .sdot, .kicker-dot { flex-shrink: 0; }
:where(main, section, article, aside, div, nav, li) { min-width: 0; }
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: var(--weight-display); text-wrap: balance; }
h1 { font-size: var(--title-size); line-height: 1.14; letter-spacing: var(--tracking-title); }
h2 { font-size: clamp(24px, 2.5vw, 32px); line-height: 1.25; letter-spacing: var(--tracking-title); }
h3 { font-size: 21px; line-height: 1.35; letter-spacing: var(--tracking-title); }
p { margin-top: 0; }
code, pre { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  overflow-x: auto;
  padding: 20px;
  border-radius: var(--r-inner);
  background: var(--panel);
  color: var(--ink-2);
  font-size: var(--text-sm);
}
pre code { overflow-wrap: normal; word-break: normal; white-space: pre; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
::selection { background: var(--accent-ring); color: var(--ink); }
.ico { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; width: 20px; height: 20px; }
.keep { white-space: nowrap; }
.muted { color: var(--muted); }
.mono { font-family: var(--font-mono); }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0;
}
.wrap { max-width: var(--content-width); margin-inline: auto; padding-inline: var(--gutter); }
.reading { max-width: var(--reading-width); margin-inline: auto; padding-inline: var(--gutter); }
.sect { position: relative; padding-top: 24px; padding-bottom: var(--section-gap); }
.decorated { position: relative; overflow-x: clip; }
.prose { overflow-wrap: break-word; }
.prose h2 { margin-top: 56px; margin-bottom: 20px; }
.prose h3 { margin-top: 32px; margin-bottom: 12px; }
.prose p, .prose ul, .prose ol { margin-bottom: 20px; }
.prose a:not([class*="btn"]):not([class*="button"]) { color: var(--accent-dark); text-decoration: underline; text-underline-offset: 3px; }
.prose :not(pre) > code { background: var(--panel); color: var(--ink-2); padding: 2px 5px; border-radius: var(--r-field); }
.prose li + li { margin-top: 8px; }
.prose img { border-radius: var(--r-card); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 10px 24px; border: 1px solid var(--clear);
  border-radius: var(--r-pill); font-size: 15.5px; font-weight: var(--weight-semibold);
  letter-spacing: -.005em; text-align: center; transition: transform var(--ease), background var(--ease);
}
.btn svg { width: 18px; height: 18px; }
.btn:hover { transform: translateY(-1px); }
.btn--primary { background: var(--accent); color: var(--bg); }
.btn--primary:hover, .btn--primary.is-hover { background: var(--accent-dark); color: var(--bg); }
.btn--soft { background: var(--accent-soft); color: var(--accent-dark); }
.btn--soft:hover { background: var(--accent-ring); color: var(--accent-dark); }
.btn--outline { background: var(--bg); color: var(--ink-2); border-color: var(--line); }
.btn--outline:hover { background: var(--panel); color: var(--ink); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--panel-2); color: var(--muted); cursor: not-allowed; transform: none; }
.btn.is-focus { outline: 3px solid var(--accent-ring); outline-offset: 3px; }
.cta-row { margin-top: 22px; display: flex; justify-content: center; flex-wrap: wrap; gap: 12px; }
.panel { background: var(--panel); color: var(--ink); border-radius: var(--r-container); padding: 40px; }
.panel-head { display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.eyebrow { margin: 0; font-size: 15px; font-weight: var(--weight-medium); color: var(--muted); }
.panel h2 { margin: 4px 0 0; font-size: 28px; }
.round-arrow {
  flex: none; display: grid; place-items: center; width: 46px; height: 46px;
  border-radius: var(--r-circle); background: var(--ink); color: var(--bg); transition: transform var(--ease);
}
.round-arrow:hover { transform: translateX(2px); }
.round-arrow svg { width: 20px; height: 20px; stroke-width: 2.2; }
.card { padding: 24px; border-radius: var(--r-card); background: var(--bg); color: var(--ink); box-shadow: var(--shadow-soft); }
.card h3 { margin: 0 0 12px; }
.card p:last-child { margin-bottom: 0; }
.card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; margin-top: 28px; }

.topbar { position: relative; z-index: 100; height: var(--header-height); background: var(--bg); color: var(--ink); }
.topbar-inner {
  position: relative; max-width: min(100%, 1376px); height: 100%; margin-inline: auto; padding-inline: 32px;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px; flex-shrink: 0;
  font-family: var(--font-display); font-weight: var(--weight-display); font-size: 17px;
  letter-spacing: -.015em; color: var(--ink);
}
.brand-mark { width: 32px; height: 32px; flex: none; }
.desktop-nav { margin-left: auto; min-width: 0; }
.nav-list { display: flex; align-items: center; gap: 2px; list-style: none; margin: 0; padding: 0; }
.nav-link {
  display: inline-flex; align-items: center; min-height: 36px; padding: 6px 15px;
  border-radius: var(--r-pill); font-size: 14.5px; font-weight: var(--weight-medium);
  color: var(--muted); white-space: nowrap;
}
.nav-link:hover { color: var(--ink); background: var(--panel); }
.nav-link[aria-current="page"] { background: var(--accent-soft); color: var(--accent-dark); font-weight: var(--weight-semibold); }
.header-tools { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.nav-sep { width: 1px; height: 20px; background: var(--line); }
.language { position: relative; }
.lang {
  display: inline-flex; align-items: center; gap: 7px; min-height: 36px; padding: 6px 14px;
  border: 1px solid var(--line); border-radius: var(--r-pill);
  background: var(--bg); color: var(--ink-2); font-size: var(--text-sm); font-weight: var(--weight-medium); white-space: nowrap;
}
.lang svg { width: 16px; height: 16px; }
.lang-caret { font-size: 11px; color: var(--muted); }
.lang-short { display: none; }
.language-menu {
  position: absolute; right: 0; top: calc(100% + 10px); width: 184px; margin: 0; padding: 8px;
  list-style: none; border: 1px solid var(--line); border-radius: var(--r-card);
  background: var(--bg); color: var(--ink); box-shadow: var(--shadow-soft);
}
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 8px 12px; border-radius: var(--r-inner); }
.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;
  border: 1px solid var(--line); border-radius: var(--r-circle); background: var(--bg); color: var(--ink);
}
.menu-toggle svg { width: 21px; height: 21px; }
.mobile-nav { display: none; }
.nav-veil { position: fixed; inset: var(--header-height) 0 0; z-index: 90; background: var(--veil); color: var(--ink); }

.site-footer { background: var(--panel); color: var(--ink); padding-top: 56px; padding-bottom: 96px; border-radius: var(--r-container) var(--r-container) 0 0; }
.footer-grid { display: grid; grid-template-columns: 1.3fr .8fr 1.4fr .7fr; gap: 36px; }
.footer-brand p { margin-top: 18px; max-width: 320px; color: var(--muted); font-size: var(--text-sm); }
.footer-title { margin: 0 0 16px; font-size: var(--text-sm); font-weight: var(--weight-bold); }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links a { display: inline-block; padding-block: 5px; font-size: var(--text-sm); color: var(--muted); }
.footer-links a:hover { color: var(--accent-dark); text-decoration: underline; text-underline-offset: 3px; }
.footer-links a[aria-current] { color: var(--accent-dark); }
.footer-bottom { margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--line); font-size: 13px; color: var(--muted); }

.reveal { opacity: 1; transform: none; }
.reveal.is-waiting { opacity: 0; transform: translateY(14px); transition: opacity 550ms ease, transform 550ms ease; }
.reveal.shown { opacity: 1; transform: none; }

@media (max-width: 1279px) {
  .topbar .brand { min-width: 0; flex-shrink: 1; }
  .topbar .brand-text { min-width: 0; overflow-wrap: anywhere; line-height: 1.3; }
  .desktop-nav { display: none; }
  .header-tools { margin-left: auto; gap: 8px; }
  .menu-toggle { display: inline-flex; }
  .nav-sep { display: none; }
  .mobile-nav:not([hidden]) {
    display: block; position: absolute; top: var(--header-height); left: 0; right: 0;
    max-height: calc(100dvh - var(--header-height)); overflow-y: auto; overscroll-behavior: contain;
    padding: 16px var(--gutter) 24px; border-top: 1px solid var(--line);
    background: var(--bg); color: var(--ink); box-shadow: var(--shadow-soft);
  }
  .mobile-nav ul { list-style: none; margin: 0; padding: 0; }
  .mobile-nav a { display: flex; align-items: center; width: 100%; min-height: 48px; padding: 12px 16px; border-radius: var(--r-inner); }
  .mobile-nav a:hover, .mobile-nav a[aria-current] { background: var(--accent-soft); color: var(--accent-dark); }
  .mobile-nav .mobile-language-title { margin: 20px 16px 8px; color: var(--muted); font-size: 13px; }
}
@media (max-width: 860px) {
  .topbar-inner { padding-inline: 16px; gap: 12px; }
  .panel { padding: 28px 22px; }
  .card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  :root { --title-size: clamp(24px, 4vw, 30px); --section-gap: 64px; }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  .tilt, [data-tilt] { transform: none !important; }
  .card-grid { grid-template-columns: minmax(0, 1fr); }
  .panel { padding: 24px 20px; }
  .panel-head { gap: 12px; }
  .panel h2 { font-size: 22px; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang { padding-inline: 11px; }
  .brand-text { font-size: 15px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .footer-brand p { max-width: none; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal.is-waiting { opacity: 1; transform: none; }
}