body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f4f4f4;
  color: #222;
}

header {
  background: #111;
  color: white;
  padding: 20px;
  text-align: center;
}

nav a {
  color: white;
  text-decoration: none;
  margin: 0 10px;
}

main {
  max-width: 900px;
  margin: 20px auto;
  padding: 20px;
  background: white;
}

img {
  max-width: 100%;
  height: auto;
}

footer {
  text-align: center;
  padding: 15px;
  background: #111;
  color: white;
}

@media (max-width: 600px) {
  nav a {
    display: block;
    margin: 10px 0;
  }
}