:root {
  --bg: #f7f8fa;
  --card: #fff;
  --text: #172033;
  --muted: #5d6678;
  --border: #e3e7ee;
  --accent: #3157d5;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}
header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
}
nav {
  max-width: 920px;
  margin: auto;
  padding: 18px 22px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  font-size: 1.35rem;
  font-weight: 750;
  color: var(--text);
  text-decoration: none;
}
nav div {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}
nav div a {
  color: var(--muted);
  text-decoration: none;
}
main {
  max-width: 920px;
  margin: 36px auto;
  padding: 0 22px;
}
article, .hero {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 34px;
}
h1 { margin-top: 0; line-height: 1.2; }
h2 { margin-top: 34px; line-height: 1.3; }
a { color: var(--accent); }
.meta, .muted { color: var(--muted); }
.button {
  display: inline-block;
  margin: 8px 8px 0 0;
  padding: 11px 17px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
}
.button.secondary {
  background: #eef1f7;
  color: var(--text);
}
footer {
  max-width: 920px;
  margin: 28px auto;
  padding: 0 22px 30px;
  color: var(--muted);
  font-size: .92rem;
}
@media (max-width: 640px) {
  nav { flex-direction: column; }
  article, .hero { padding: 23px; }
  main { margin-top: 22px; }
}