body {
  margin: 0;
  font-family: sans-serif;
  line-height: 1.7;
  color: #222;
}

/* 左右の余白 */
.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
}

nav {
  padding: 24px 0;
  border-bottom: 1px solid #ddd;
}

nav a {
  margin-right: 20px;
  color: #222;
  text-decoration: none;
}

nav a:hover {
  text-decoration: underline;
}

main {
  padding: 32px 0;
}