body {
  font-family: 'Roboto', Arial, sans-serif;
  margin: 0;
  background: #f8fafc;
  color: #222;
}
header {
  background: #1a237e;
  color: #fff;
  padding: 2rem 0 1rem 0;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
header h1 {
  margin: 0 0 0.5rem 0;
  font-size: 2.5rem;
  font-weight: 700;
}
header p {
  margin: 0 0 1rem 0;
  font-size: 1.2rem;
  font-weight: 400;
}
nav {
  margin: 1rem 0 0 0;
}
nav a {
  color: #fff;
  text-decoration: underline;
  margin: 0 1.5rem;
  font-weight: 500;
  font-size: 1.1rem;
}
main {
  max-width: 900px;
  margin: 2rem auto;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.06);
  padding: 2rem 2.5rem;
}
h2 {
  color: #1a237e;
  margin-top: 2rem;
}
ul {
  line-height: 1.7;
}
.footer {
  text-align: center;
  color: #888;
  font-size: 0.95rem;
  margin: 3rem 0 1rem 0;
}
.button {
  display: inline-block;
  background: #1a237e;
  color: #fff;
  padding: 0.7em 1.5em;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 600;
  margin: 1.5em 0;
  transition: background 0.2s;
}
.button:hover {
  background: #3949ab;
}
@media (max-width: 600px) {
  main { padding: 1rem; }
  header h1 { font-size: 1.5rem; }
}
pre {
  background: #f4f6fb;
  padding: 1em;
  border-radius: 6px;
  overflow-x: auto;
  font-size: 0.97em;
}