* {
  box-sizing: border-box;
}

body {
  margin: 0;
}

wrapper {
  display: flex;
  flex-direction: column;
}

header {
  background-color: lightgreen;
  padding: 10px;
}

nav {
  background-color: green;
  padding: 10px;
}

nav a {
  display: inline-block;
  text-decoration: none;
  color: white;
  border: 2px solid lightgreen;
  border-radius: 2px;
  padding: 10px;
  margin: 10px;
}

main img {
  width: 30%;
}