:root {
  --bg: #f6f8fb;
  --ink: #162033;
  --muted: #667085;
  --line: #dfe6ef;
  --panel: #ffffff;
  --accent: #1769e0;
  --accent-soft: #eaf2ff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
}

.site-header {
  height: 68px;
  padding: 0 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #fff;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 800;
}

.brand span {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: #fff;
}

nav {
  display: flex;
  gap: 18px;
}

nav a,
footer a {
  color: var(--muted);
  text-decoration: none;
}

main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 48px 28px;
}

.hero {
  padding: 54px 0 46px;
}

.eyebrow {
  margin: 0 0 16px;
  color: var(--accent);
  font-weight: 800;
}

h1 {
  max-width: 880px;
  margin: 0;
  font-size: 48px;
  line-height: 1.15;
  letter-spacing: 0;
}

.lead {
  max-width: 760px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.8;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.primary,
.secondary {
  min-height: 42px;
  padding: 0 18px;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  font-weight: 800;
}

.primary {
  background: var(--accent);
  color: #fff;
}

.secondary {
  background: var(--accent-soft);
  color: var(--accent);
}

.grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

article,
.doc {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
}

article {
  padding: 22px;
}

article h2,
.doc h2 {
  margin: 0 0 12px;
  font-size: 20px;
}

article p,
.doc p {
  margin: 0;
  color: var(--muted);
  line-height: 1.75;
}

.doc {
  max-width: 900px;
  padding: 36px;
}

.doc h1 {
  font-size: 34px;
}

.doc h2 {
  margin-top: 28px;
}

.muted {
  margin-top: 12px;
  color: var(--muted);
}

footer {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px 28px 46px;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  color: var(--muted);
}

@media (max-width: 880px) {
  .site-header {
    height: auto;
    padding: 18px;
    align-items: flex-start;
    gap: 14px;
    flex-direction: column;
  }

  h1 {
    font-size: 34px;
  }

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

  footer {
    flex-direction: column;
  }
}