:root {
  color-scheme: dark;
  --bg: #020617;
  --surface: rgba(15, 23, 42, 0.78);
  --surface-strong: #0f172a;
  --line: rgba(148, 163, 184, 0.2);
  --text: #e2e8f0;
  --muted: #94a3b8;
  --cyan: #67e8f9;
  --blue: #60a5fa;
  --green: #86efac;
  --max: 1120px;
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at 75% 0%, rgba(14, 116, 144, 0.2), transparent 32rem),
    radial-gradient(circle at 5% 30%, rgba(30, 64, 175, 0.14), transparent 26rem),
    var(--bg);
  line-height: 1.75;
}

a { color: inherit; }

a:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 4px;
  border-radius: 4px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 1rem;
  left: 1rem;
  padding: 0.65rem 1rem;
  color: #082f49;
  background: var(--cyan);
  border-radius: 0.5rem;
  transform: translateY(-160%);
}

.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(2, 6, 23, 0.88);
  backdrop-filter: blur(16px);
}

.nav,
.page-shell,
.site-footer__inner {
  width: min(calc(100% - 2rem), var(--max));
  margin-inline: auto;
}

.nav {
  min-height: 4.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand,
.nav__links,
.actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand {
  text-decoration: none;
  font-weight: 800;
  letter-spacing: 0.04em;
}

.brand__mark {
  width: 2.1rem;
  height: 2.1rem;
  display: grid;
  place-items: center;
  color: #082f49;
  background: linear-gradient(135deg, var(--cyan), var(--blue));
  border-radius: 0.65rem;
}

.nav__links a,
.footer-links a,
.breadcrumb a {
  color: var(--muted);
  text-decoration: none;
}

.nav__links a:hover,
.footer-links a:hover,
.breadcrumb a:hover { color: var(--cyan); }

.page-shell { padding: 2rem 0 5rem; }

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.hero { padding: clamp(3rem, 9vw, 7rem) 0 4rem; }

.eyebrow {
  margin: 0 0 1rem;
  color: var(--cyan);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1,
h2,
h3 { line-height: 1.2; }

h1 {
  max-width: 1040px;
  margin: 0;
  font-size: clamp(2.25rem, 6vw, 4.8rem);
  letter-spacing: -0.04em;
  text-wrap: balance;
}

h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.55rem, 3vw, 2.35rem);
}

h3 { margin: 0 0 0.65rem; }

.lead {
  max-width: 780px;
  margin: 1.5rem 0 0;
  color: #cbd5e1;
  font-size: clamp(1.05rem, 2vw, 1.25rem);
}

.actions { margin-top: 2rem; flex-wrap: wrap; }

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.9rem;
  padding: 0.7rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  text-decoration: none;
  font-weight: 750;
}

.button--primary {
  color: #082f49;
  background: linear-gradient(135deg, var(--cyan), #a5f3fc);
  border-color: transparent;
}

.button:hover { transform: translateY(-1px); }

.section {
  padding: 3.5rem 0;
  border-top: 1px solid var(--line);
}

.section__intro {
  max-width: 760px;
  margin-bottom: 1.75rem;
  color: var(--muted);
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.card,
.fact,
.note {
  padding: 1.35rem;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
}

.card p,
.fact p { margin: 0; color: var(--muted); }

.card__number {
  display: block;
  margin-bottom: 1rem;
  color: var(--cyan);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}

.fact strong {
  display: block;
  color: var(--cyan);
  font-size: clamp(1.35rem, 3vw, 2rem);
}

.note {
  border-left: 3px solid var(--cyan);
  color: #cbd5e1;
}

.check-list {
  padding: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  margin: 0.75rem 0;
  padding-left: 1.75rem;
}

.check-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--green);
  font-weight: 800;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: rgba(2, 6, 23, 0.72);
}

.site-footer__inner {
  padding: 2.2rem 0;
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  color: var(--muted);
}

.footer-links { display: flex; flex-wrap: wrap; gap: 1rem; }

@media (max-width: 760px) {
  .nav { align-items: flex-start; padding: 1rem 0; }
  .nav__links { display: none; }
  .grid,
  .grid--2,
  .facts { grid-template-columns: 1fr; }
  .site-footer__inner { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}