body {
  font-family: Arial, sans-serif;
  margin: 0; padding: 0;
  background: #fdfdfd; color: #222;
}
header {
  background: #ffeb3b;
  padding: 20px; text-align: center;
}
header h1 { margin: 0; }
nav a { margin: 0 8px; text-decoration: none; color: #006d77; font-weight: bold; }
nav a:hover { text-decoration: underline; }
main { max-width: 900px; margin: 20px auto; padding: 0 20px; }
footer {
  text-align: center; padding: 15px; font-size: 0.9em;
  background: #eee; margin-top: 30px;
}