* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Segoe UI', sans-serif;
  line-height: 1.6;
  background: #f4f4f4;
  padding: 20px;
}

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

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

nav {
  margin-top: 10px;
}

main {
  margin-top: 20px;
}

figure {
  margin-bottom: 20px;
}

img {
  width: 100%;
  max-width: 500px;
  height: auto;
  display: block;
}

figcaption {
  text-align: center;
  font-style: italic;
  margin-top: 5px;
}

footer {
  margin-top: 40px;
  text-align: center;
  color: #555;
}

@media (max-width: 600px) {
  nav a {
    display: block;
    margin: 5px 0;
  }

  img {
    max-width: 100%;
  }
}