:root {
  color-scheme: light;
  --bg: #f4fbff;
  --panel: #ffffff;
  --text: #111827;
  --muted: #5f6f7a;
  --line: #cfe5ec;
  --accent: #0bb7d5;
  --accent-strong: #087c96;
  --ink: #071923;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  color: var(--text);
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    "PingFang SC",
    "Hiragino Sans GB",
    "Microsoft YaHei",
    sans-serif;
  line-height: 1.65;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

.site-header,
.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
  padding: 24px 0;
}

.brand {
  color: var(--ink);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0;
  text-decoration: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 15px;
}

.nav-links a {
  color: var(--ink);
  text-decoration: none;
}

.nav-links a[aria-current="page"] {
  color: var(--accent-strong);
  font-weight: 700;
}

main {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
}

.hero {
  min-height: 56vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 56px 0 72px;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent-strong);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  max-width: 780px;
  margin: 0;
  color: var(--ink);
  font-size: clamp(48px, 8vw, 92px);
  line-height: 0.95;
  letter-spacing: 0;
}

.hero-copy {
  max-width: 690px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: 20px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.button.primary {
  border-color: var(--accent);
  background: var(--accent);
  color: #00141a;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}

.feature-grid article,
.status-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.84);
  padding: 22px;
}

h2 {
  margin: 0 0 10px;
  color: var(--ink);
  font-size: 22px;
  line-height: 1.25;
}

h3 {
  margin: 22px 0 6px;
  color: var(--ink);
  font-size: 17px;
}

p {
  margin: 0 0 14px;
}

.feature-grid p,
.status-panel p,
.document p {
  color: var(--muted);
}

.document {
  max-width: 820px;
  padding: 64px 0 76px;
}

.document h1 {
  margin-bottom: 28px;
  font-size: clamp(38px, 6vw, 64px);
}

.document h2 {
  margin-top: 34px;
}

.site-footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 860px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 620px) {
  .site-header,
  .site-footer {
    width: min(100% - 28px, 1080px);
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  main {
    width: min(100% - 28px, 1080px);
  }

  .hero {
    min-height: auto;
    padding: 44px 0 48px;
  }

  .hero-copy {
    font-size: 17px;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }
}