:root {
  --bg: #F5F4F0;
  --bg-panel: #FFFFFF;
  --bg-panel-2: #ECEAE3;
  --line: #E2E0D9;
  --line-strong: #D3D0C6;
  --accent: #103547;
  --accent-dark: #0A2331;
  --accent-soft: #1B4A62;
  --accent-tint: rgba(16, 53, 71, 0.07);
  --accent-ring: rgba(16, 53, 71, 0.16);
  --cta: #F5C44F;
  --cta-hover: #EDB93A;
  --coral: #DD7355;
  --coral-ink: #B4513A;
  --coral-halo: rgba(221, 115, 85, 0.45);
  --text: #0F2A3A;
  --text-muted: #5E6B73;
  --text-faint: #8C969B;
  --on-accent: #FFFFFF;
  --success: #2F8F6B;
  --warn: #E9A93A;
  --error: #C8553D;
  --icon-navy-bg: rgba(16, 53, 71, 0.09);
  --icon-coral-bg: rgba(221, 115, 85, 0.12);
  --icon-yellow-bg: rgba(245, 196, 79, 0.24);
  --icon-cool-bg: rgba(94, 107, 115, 0.12);
  --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-frame: 36px;
  --r-card: 24px;
  --r-window: 20px;
  --r-tag: 16px;
  --r-field: 10px;
  --r-tiny: 6px;
  --r-pill: 999px;
  --shadow-soft: 0 1px 2px rgba(15, 42, 58, 0.05), 0 10px 24px -14px rgba(15, 42, 58, 0.22);
  --shadow-window: 0 2px 4px rgba(5, 20, 30, 0.22), 0 34px 64px -22px rgba(3, 14, 22, 0.62);
  --shadow-tag: 0 2px 6px rgba(15, 42, 58, 0.10), 0 18px 34px -14px rgba(15, 42, 58, 0.38);
  --shadow-cta: 0 1px 0 rgba(10, 35, 49, 0.10), 0 12px 22px -12px rgba(190, 132, 20, 0.75);
  --wrap-max: 1440px;
  --gutter: 48px;
  --header-h: 72px;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  min-width: 320px;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
main, section { min-width: 0; }
a { color: inherit; }
button, input, select { font: inherit; }
button { cursor: pointer; }
img, svg { max-width: 100%; }
img { display: block; }
code, pre { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre { max-width: 100%; overflow-x: auto; white-space: pre; }
pre code { overflow-wrap: normal; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
h1, h2, h3 { font-family: var(--font-display); color: var(--accent); letter-spacing: -0.02em; text-wrap: balance; }
h1 { font-size: clamp(34px, 3.5vw, 48px); line-height: 1.18; font-weight: 800; }
h2 { font-size: clamp(25px, 2.6vw, 36px); line-height: 1.25; font-weight: 800; }
h3 { font-size: clamp(19px, 1.8vw, 24px); line-height: 1.35; font-weight: 800; }
.nowrap-term { white-space: nowrap; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip { position: absolute; left: 16px; top: -60px; z-index: 100; padding: 10px 18px; border-radius: var(--r-pill); background: var(--accent); color: var(--on-accent); font-weight: 700; text-decoration: none; }
.skip:focus { top: 12px; }
.wrap { width: 100%; max-width: var(--wrap-max); margin-inline: auto; padding-inline: var(--gutter); }
.reading { max-width: 840px; min-width: 0; }
.section-space { padding-block: 76px; }
.section-white { background: var(--bg-panel); color: var(--text); }
.section-muted { background: var(--bg-panel-2); color: var(--text); }
.section-navy { background: var(--accent); color: var(--on-accent); border-radius: var(--r-frame); }
.section-navy h2, .section-navy h3 { color: var(--on-accent); }
.panel-card { min-width: 0; padding: 28px; border: 1px solid var(--line); border-radius: var(--r-card); background: var(--bg-panel); color: var(--text); box-shadow: var(--shadow-soft); }
.section-label { margin: 0 0 12px; color: var(--coral-ink); font-size: 12.5px; font-weight: 700; letter-spacing: 0.14em; }
.prose { min-width: 0; max-width: 76ch; line-height: 1.85; }
.prose h2 { margin-block: 2.4em 0.7em; scroll-margin-top: 90px; }
.prose h3 { margin-block: 1.8em 0.6em; }
.prose p, .prose li { overflow-wrap: break-word; }
.prose a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
.prose pre { padding: 20px; border-radius: var(--r-tag); background: var(--accent-dark); color: var(--on-accent); }
.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.65s ease, transform 0.65s ease; }
.reveal.shown { opacity: 1; transform: none; }

/* The header has its own, wider measure. Its four direct children stay independent. */
.masthead {
  position: relative;
  z-index: 40;
  width: 100%;
  max-width: min(100%, calc(1280px + var(--gutter) * 2));
  min-height: var(--header-h);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 24px;
}
.brand { display: inline-flex; align-items: center; gap: 11px; flex: none; text-decoration: none; }
.brand__mark { width: 36px; height: 36px; flex: none; }
.brand__name { font-family: var(--font-display); font-size: 18px; font-weight: 800; letter-spacing: -0.01em; color: var(--accent); white-space: nowrap; }
.mainnav { margin-left: auto; min-width: 0; }
.mainnav ul { display: flex; align-items: center; gap: 2px; list-style: none; margin: 0; padding: 0; }
.mainnav a {
  display: inline-flex; align-items: center; gap: 7px; padding: 8px 12px;
  border-radius: var(--r-pill); color: var(--text); font-size: 14.5px;
  font-weight: 500; text-decoration: none; white-space: nowrap;
  transition: background-color 0.18s ease, color 0.18s ease;
}
.mainnav svg { width: 17px; height: 17px; flex: none; color: var(--text-muted); }
.mainnav a:hover, .mainnav a[aria-current="page"] { background: var(--accent-tint); color: var(--accent); }
.mainnav a[aria-current="page"] { font-weight: 700; }
.mainnav a:hover svg, .mainnav a[aria-current="page"] svg { color: var(--accent); }
.masthead__tools { display: flex; align-items: center; gap: 14px; flex: none; }
.masthead__rule { width: 1px; height: 22px; background: var(--line-strong); }
.lang-area { position: relative; }
.lang {
  display: inline-flex; align-items: center; gap: 7px; min-height: 38px;
  padding: 0 14px 0 12px; border: 1px solid var(--line-strong);
  border-radius: var(--r-pill); background: var(--bg-panel); color: var(--text);
  font-size: 14px; font-weight: 500; white-space: nowrap;
}
.lang:hover { border-color: var(--accent); }
.lang svg { width: 16px; height: 16px; flex: none; color: var(--text-muted); }
.lang__caret { font-size: 11px; color: var(--text-muted); }
.lang__short { display: none; }
.lang-menu {
  position: absolute; top: calc(100% + 10px); right: 0; width: 180px; z-index: 45;
  padding: 7px; border: 1px solid var(--line); border-radius: var(--r-tag);
  background: var(--bg-panel); color: var(--text); box-shadow: var(--shadow-tag);
}
.lang-menu[hidden], .mobile-drawer[hidden], .nav-veil[hidden] { display: none !important; }
.lang-menu a { display: block; padding: 9px 12px; border-radius: var(--r-field); text-decoration: none; }
.lang-menu a:hover, .lang-menu a[aria-current="page"] { background: var(--accent-tint); color: var(--accent); }
.menu-toggle {
  display: none; place-items: center; min-width: 44px; min-height: 44px;
  padding: 8px; border: 1px solid var(--line); border-radius: 50%;
  background: var(--bg-panel); color: var(--accent);
}
.menu-toggle svg { width: 23px; height: 23px; }
.mobile-drawer { display: none; }
.nav-veil { position: fixed; inset: 0; z-index: 30; border: 0; background: var(--accent-ring); }
#site-header { position: relative; z-index: 40; }
#site-header .masthead { max-width: min(100%, calc(1280px + var(--gutter) * 2)); }

/* Pill buttons and footer */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  min-height: 54px; padding: 0 28px; border: 1.5px solid transparent;
  border-radius: var(--r-pill); font-size: 16px; font-weight: 700;
  line-height: 1.25; text-decoration: none; text-align: center;
  transition: transform 0.18s ease, background-color 0.18s ease, box-shadow 0.18s ease;
}
.btn svg { width: 18px; height: 18px; flex: none; }
.btn--main { background: var(--cta); color: var(--accent); box-shadow: var(--shadow-cta); }
.btn--main:hover { background: var(--cta-hover); transform: translateY(-1px); }
.btn--ghost { border-color: var(--accent); color: var(--accent); background: transparent; }
.btn--ghost:hover { background: var(--accent-tint); transform: translateY(-1px); }
.btn--navy { background: var(--accent); color: var(--on-accent); }
.btn--navy:hover { background: var(--accent-dark); transform: translateY(-1px); }
.btn:disabled, .btn.is-disabled { opacity: 0.55; cursor: not-allowed; transform: none; }
.site-footer { padding-top: 64px; border-top: 1px solid var(--line); background: var(--bg-panel); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: minmax(0, 1.3fr) repeat(3, minmax(0, 1fr)); gap: 42px; }
.footer-grid > * { min-width: 0; }
.footer-grid h2 { margin: 0 0 16px; font-size: 15px; }
.footer-intro { max-width: 28em; color: var(--text-muted); font-size: 14px; }
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links a { display: inline-block; padding-block: 5px; color: var(--text-muted); text-decoration: none; font-size: 14px; }
.footer-links a:hover { color: var(--accent); text-decoration: underline; }
.footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; margin-top: 58px; padding-block: 20px; border-top: 1px solid var(--line); color: var(--text-muted); font-size: 13px; }
.footer-bottom a { margin-left: 18px; }
.footer-bottom a:hover { color: var(--accent); }

@media (max-width: 1279px) {
  .mainnav { display: none; }
  .masthead__tools { margin-left: auto; }
  .menu-toggle { display: grid; }
  .mobile-drawer {
    position: absolute; top: 100%; left: var(--gutter); right: var(--gutter);
    z-index: 45; display: block; max-height: calc(100dvh - var(--header-h) - 20px);
    overflow-y: auto; overscroll-behavior: contain; padding: 10px;
    border: 1px solid var(--line); border-radius: var(--r-card);
    background: var(--bg-panel); color: var(--text); box-shadow: var(--shadow-tag);
  }
  .mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
  .mobile-drawer a { display: flex; align-items: center; gap: 12px; width: 100%; min-height: 48px; padding: 10px 14px; border-radius: var(--r-field); text-decoration: none; }
  .mobile-drawer svg { width: 19px; height: 19px; flex: none; }
  .mobile-drawer a:hover, .mobile-drawer a[aria-current="page"] { background: var(--accent-tint); color: var(--accent); }
  .mobile-drawer__langs { margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--line); }
  .mobile-drawer__label { margin: 4px 14px; color: var(--text-muted); font-size: 13px; }
}
@media (max-width: 800px) {
  :root { --gutter: 28px; }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  h1 { font-size: clamp(24px, 4vw, 30px); }
}
@media (max-width: 640px) {
  :root { --gutter: 20px; }
  .masthead { gap: 8px; }
  .masthead__tools { gap: 8px; margin-left: auto; }
  .masthead__rule { display: none; }
  .lang__full { display: none; }
  .lang__short { display: inline; }
  .brand__name { font-size: 15px; }
  .brand__mark { width: 32px; height: 32px; }
  .lang { padding-inline: 10px; }
  .mobile-drawer { left: var(--gutter); right: var(--gutter); }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 24px; }
  .footer-bottom { margin-top: 36px; }
  .section-space { padding-block: 52px; }
  .panel-card { padding: 20px; }
  .btn { min-height: 50px; padding-inline: 20px; }
  .tilt, .card-tilt { transform: none !important; }
}
@media (max-width: 360px) {
  :root { --gutter: 16px; }
  .brand { gap: 6px; }
  .brand__name { font-size: 13px; }
  .lang { gap: 4px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .btn, .mainnav a { transition: none; }
  .btn:hover { transform: none; }
}