:root {
  --bg: #f4f7fb;
  --surface: #ffffff;
  --text: #172033;
  --muted: #5c667a;
  --border: #dbe2ec;
  --accent: #234a78;
  --accent-dark: #173553;
  --max: 900px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}
header {
  background: linear-gradient(135deg, var(--accent-dark), var(--accent));
  color: white;
  padding: 20px 24px;
}
nav {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}
.brand {
  color: white;
  text-decoration: none;
  font-weight: 750;
  font-size: 1.25rem;
  letter-spacing: .2px;
}
.links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}
.links a {
  color: #e8f0fb;
  text-decoration: none;
  font-size: .93rem;
}
.links a:hover { text-decoration: underline; }
main {
  max-width: var(--max);
  margin: 36px auto;
  padding: 0 20px;
}
article, .hero, .card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  box-shadow: 0 8px 26px rgba(31, 45, 61, .06);
}
.hero { padding: 42px 32px; }
h1 { line-height: 1.2; margin-top: 0; font-size: clamp(2rem, 5vw, 3.25rem); }
article h1 { font-size: clamp(1.85rem, 4vw, 2.6rem); }
h2 { margin-top: 2.1rem; line-height: 1.3; color: var(--accent-dark); }
h3 { margin-top: 1.5rem; }
p, li { color: var(--text); }
.muted { color: var(--muted); }
.notice {
  border-left: 4px solid var(--accent);
  background: #edf4fc;
  padding: 14px 16px;
  border-radius: 8px;
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 16px;
  margin-top: 24px;
}
.card { padding: 20px; }
.button {
  display: inline-block;
  background: var(--accent);
  color: white;
  text-decoration: none;
  padding: 11px 18px;
  border-radius: 9px;
  font-weight: 650;
}
.button:hover { background: var(--accent-dark); }
a { color: #1d5b98; }
footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 22px 20px 40px;
  color: var(--muted);
  font-size: .9rem;
}
code {
  background: #edf1f6;
  padding: 2px 5px;
  border-radius: 5px;
}
@media (max-width: 680px) {
  nav { align-items: flex-start; flex-direction: column; }
  article, .hero { padding: 22px; }
}