nav {
  background: rgba(0, 128, 128, 0.85);
  padding: 1.5em 0;
  text-align: center;
}

nav a {
  margin: 0 25px;
  color: white;
  text-decoration: none;
  font-weight: bold;
  font-size: 2.4em;
}

nav ul {
  list-style: none;
  padding: 0;
}

@media (max-width: 768px) {
  nav {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1em 0.5em;
  }

  nav a {
    display: block;
    margin: 10px 0;
    font-size: 1.6em;
  }
}