body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #fff;
  color: #000;
}
header {
  background: #000;
  color: #fff;
  text-align: center;
  padding: 20px 10px 10px;
}
nav {
  background: #111;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  padding: 10px 0;
}
nav a {
  color: #fff;
  text-decoration: none;
  margin: 0 15px;
  padding: 8px;
}
nav a:hover {
  background: #444;
  border-radius: 5px;
}
.section {
  padding: 30px;
  text-align: center;
}
ul {
  list-style-type: disc;
  padding-left: 20px;
  text-align: left;
  display: inline-block;
}
footer {
  text-align: center;
  padding: 20px;
  background: #eee;
  color: #555;
}
img {
  width: 90%;
  max-width: 700px;
  border-radius: 10px;
  margin-top: 20px;
}
@media (max-width: 600px) {
  nav {
    flex-direction: column;
  }
}