:root {
  color-scheme: light;
  --background: #f5f6f7;
  --surface: #ffffff;
  --ink: #1d1d1f;
  --muted: #5f636a;
  --line: #d9dde1;
  --accent: #9bdbea;
  --action: #076c91;
  --action-hover: #05536f;
  --font-body: 16px;
  --font-lead: 20px;
  --font-display: clamp(64px, 5.3vw, 76px);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --content-width: 1200px;
  --gutter: 32px;
  --button-radius: 999px;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--background); color: var(--ink); font: var(--font-body)/1.75 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif; }
main, .site-header, .site-footer { max-width: calc(var(--content-width) + 2 * var(--gutter)); margin-inline: auto; padding: var(--space-4) var(--gutter); }
.site-header { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: var(--space-2) var(--space-4); padding-block: 20px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: var(--space-1); color: var(--ink); font-size: 24px; font-weight: 650; letter-spacing: -.03em; text-decoration: none; }
.brand img { width: 34px; height: 34px; object-fit: contain; }
.site-nav { display: flex; flex-wrap: wrap; gap: var(--space-1) var(--space-4); margin: 0; padding: 0; list-style: none; }
.site-nav a { display: inline-flex; align-items: center; min-height: 44px; color: var(--ink); font-size: 14px; text-decoration: none; }
.site-nav a:hover { text-decoration: underline; text-underline-offset: 5px; }
a { color: var(--action); text-underline-offset: 4px; }
a:focus-visible, summary:focus-visible { outline: 3px solid var(--action); outline-offset: 5px; border-radius: 3px; }
.support-nav { display: flex; align-items: center; gap: var(--space-3); }
.language-menu { position: relative; }
.language-menu summary { display: flex; align-items: center; gap: 8px; min-height: 44px; font-size: 14px; cursor: pointer; list-style: none; }
.language-menu summary::-webkit-details-marker { display: none; }
.language-menu summary::after { content: ""; width: 6px; height: 6px; border-right: 1px solid currentColor; border-bottom: 1px solid currentColor; transform: rotate(45deg); margin-top: -4px; }
.language-options { position: absolute; z-index: 3; top: 100%; right: 0; min-width: 132px; margin: 4px 0 0; padding: 8px; list-style: none; background: var(--surface); border: 1px solid var(--line); border-radius: 8px; box-shadow: 0 8px 24px #1d1d1f14; }
.language-options a { display: flex; padding-inline: 12px; border-radius: 4px; }
.language-options a:hover, .language-options a[aria-current="page"] { background: var(--background); }
[aria-current="page"] { font-weight: 700; }
.skip-link { position: absolute; z-index: 2; top: var(--space-1); left: var(--space-1); padding: var(--space-1) var(--space-2); background: var(--surface); transform: translateY(-200%); }
.skip-link:focus { transform: translateY(0); }
h1 { font-size: var(--font-display); font-weight: 650; line-height: 1.15; letter-spacing: -.04em; margin: var(--space-2) 0 var(--space-3); }
h2 { font-size: 23px; margin: 0 0 18px; }
p { color: var(--muted); margin: 14px 0; }
.eyebrow { font-size: 14px; font-weight: 600; letter-spacing: .08em; color: var(--muted); }
.lead { font-size: var(--font-lead); max-width: 680px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; background: var(--action); color: var(--surface); text-decoration: none; padding: 11px 26px; border-radius: var(--button-radius); font-weight: 600; }
.button:hover { background: var(--action-hover); }
.secondary-action { display: inline-flex; align-items: center; gap: var(--space-1); min-height: 48px; text-decoration: none; }
.secondary-action:hover { text-decoration: underline; }
.site-footer { border-top: 1px solid var(--line); font-size: 13px; color: var(--muted); display: flex; align-items: baseline; justify-content: space-between; gap: var(--space-3) var(--space-4); flex-wrap: wrap; padding-block: var(--space-4); }
.site-footer p { margin: 0; }
.site-footer a { color: var(--muted); }

@media (max-width: 720px) {
  :root { --gutter: 24px; --font-display: clamp(36px, 9.7vw, 44px); --font-lead: 18px; }
  .site-header { padding-block: var(--space-2); gap: var(--space-1) var(--space-2); }
  .brand { font-size: 22px; }
  .site-nav { gap: var(--space-2); }
  .site-nav a { font-size: 13px; }
  .support-nav { gap: var(--space-2); }
  .language-menu summary { font-size: 13px; }
  .site-footer { flex-direction: column; gap: var(--space-2); }
}

@media (max-width: 380px) {
  .site-header nav { width: 100%; }
  .site-nav { justify-content: space-between; }
}