@charset "UTF-8";

/* Inter 本地托管（SIL OFL 1.1，许可见 assets/fonts/Inter-OFL.txt），不依赖外部字体服务 */
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url("assets/fonts/inter-latin-opsz.woff2") format("woff2");
}

:root {
  color-scheme: light;
  --paper: #f5f7f6;
  --ink: #173b54;
  --muted: #536774;
  --accent: #216d75;
  --line: #dbe3e5;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

* { box-sizing: border-box; }
body { margin: 0; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; }
.wrap { width: min(1184px, calc(100% - 96px)); margin-inline: auto; }
a:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; }
.skip-link { position: absolute; top: -80px; left: 24px; padding: 12px 20px; background: white; z-index: 2; }
.skip-link:focus { top: 12px; }

.site-header { border-bottom: 1px solid var(--line); background: #fff; }
.header-inner { min-height: 96px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 22px; }
.brand img { display: block; width: 144px; height: auto; }
.brand-name { border-left: 1px solid var(--line); padding-left: 22px; font-size: 15px; line-height: 1.45; font-weight: 600; letter-spacing: .01em; }
nav { display: flex; align-items: center; gap: 34px; font-size: 14px; }
nav a { min-height: 44px; display: inline-flex; align-items: center; gap: 12px; }
nav a:hover { color: var(--accent); text-decoration: underline; text-underline-offset: 5px; }

.hero { display: grid; grid-template-columns: 1fr 1.06fr; align-items: center; gap: 56px; padding-block: 64px 60px; }
.eyebrow { display: flex; align-items: center; gap: 10px; margin: 0 0 24px; font-size: 11px; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--accent); }
.eyebrow > span { display: inline-block; width: 22px; height: 2px; background: currentColor; }
h1 { margin: 0; font-size: clamp(40px, 4.6vw, 64px); line-height: 1.04; letter-spacing: -.035em; font-weight: 600; }
.intro { max-width: 365px; margin: 24px 0 28px; color: var(--muted); font-size: 16px; line-height: 1.7; }
.explore-link { display: inline-flex; align-items: center; gap: 24px; min-height: 44px; padding-block: 8px; border-bottom: 1px solid #a6b9bf; font-size: 13px; font-weight: 600; }
.explore-link > span { font-size: 19px; font-weight: 400; }
.explore-link:hover { color: var(--accent); border-color: var(--accent); }
.hero-photo { margin: 0; background: var(--ink); border-radius: 5px; overflow: hidden; }
.hero-photo > img { display: block; width: 100%; height: auto; aspect-ratio: 3 / 2; object-fit: cover; }
.hero-photo figcaption { display: flex; justify-content: space-between; align-items: center; padding: 15px 20px; color: #f1f6f8; font-size: 11px; letter-spacing: .05em; }

.collaborations { padding-bottom: 48px; }
.section-heading { display: flex; align-items: center; gap: 24px; margin-bottom: 24px; }
.section-heading h2 { margin: 0; font-size: 20px; font-weight: 600; letter-spacing: -.02em; }
.section-rule { flex: 1; height: 1px; background: var(--line); }
.network-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin: 0; padding: 0; list-style: none; }
.network { padding: 28px 24px 24px; border: 1px solid var(--line); border-radius: 5px; background: #fff; }
.flags { display: flex; align-items: center; gap: 8px; }
/* 国旗只定高度，宽度按各 SVG 自身比例计算 */
.flags img { display: block; width: auto; height: 36px; border-radius: 2px; box-shadow: 0 0 0 1px rgba(23, 59, 84, .14); }
.network h3 { margin: 22px 0 0; font-size: 17px; line-height: 1.4; font-weight: 600; letter-spacing: -.025em; }
.network h3 > span { color: #81949f; margin-inline: 3px; font-weight: 400; }

.contact { display: flex; justify-content: space-between; align-items: center; gap: 40px; padding: 36px 40px; background: #e8efef; border-radius: 5px; }
.contact h2 { max-width: 600px; margin: 0; font-size: 26px; line-height: 1.3; font-weight: 550; letter-spacing: -.02em; }
.contact-email { flex: none; margin: 0; font-size: 17px; }
.site-footer { padding-block: 28px 32px; font-size: 11px; line-height: 1.6; color: var(--muted); }
.site-footer p { margin: 0; }
.site-footer p > span { margin-inline: 10px; color: #a4b4bd; }

@media (min-width: 1500px) {
  .hero { padding-block: 80px 68px; }
}

@media (max-width: 1050px) {
  .wrap { width: calc(100% - 64px); }
  .hero { gap: 32px; padding-block: 48px; }
  .network { padding: 24px 20px 20px; }
  .network h3 { font-size: 16px; }
}

@media (max-width: 900px) {
  .network-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 760px) {
  .wrap { width: calc(100% - 40px); }
  .header-inner { min-height: 80px; gap: 16px; }
  .brand { gap: 14px; }
  .brand img { width: 116px; }
  .brand-name { padding-left: 14px; font-size: 12px; }
  nav { gap: 20px; font-size: 12px; }
  .hero { gap: 32px; grid-template-columns: 1fr; padding-block: 40px; }
  h1 { font-size: clamp(38px, 9vw, 52px); }
  .eyebrow { margin-bottom: 20px; }
  .intro { max-width: 420px; margin-block: 20px 16px; font-size: 15px; }
  .network-grid { gap: 12px; }
  .contact { flex-direction: column; align-items: flex-start; gap: 18px; padding: 28px; }
  .contact h2 { font-size: 24px; }
}

@media (max-width: 480px) {
  .brand-name { display: none; }
  .brand img { width: 104px; }
  nav { gap: 16px; font-size: 11px; }
  .hero { padding-top: 32px; gap: 28px; }
  .intro { margin-top: 18px; }
  .hero-photo figcaption { padding: 12px 16px; }
  .section-heading { margin-bottom: 18px; }
  .section-heading h2 { font-size: 19px; }
  .network-grid { grid-template-columns: 1fr; }
  .network { display: flex; align-items: center; gap: 16px; padding: 18px 20px; }
  .flags { flex: none; min-width: 104px; gap: 6px; }
  .flags img { height: 28px; }
  .network h3 { margin: 0; font-size: 15px; }
  .network h3 > span { margin-inline: 1px; }
  .collaborations { padding-bottom: 32px; }
  .contact { padding: 28px 24px; }
  .contact h2 { font-size: 22px; }
  .site-footer { padding-block: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  :root { scroll-behavior: auto; }
}