body {
  padding: 20px;
  font-family: Verdana, Geneva, Tahoma, sans-serif;
}
nav {
  max-width: 960px;
}
nav ul {
  border: 1px solid #000;
  list-style-type: none;
  display: flex;
  flex-direction: row;
  padding: 0;
}
nav a {
  text-decoration: none;
  color: #000;
  font-size: 1.2rem;
  border: 2px solid rgb(96, 139, 168);
  border-radius: 5px;
  background-color: rgba(96, 139, 168, 0.2);
  display: block;
  padding: 10px;
  margin: 10px;
}

#nav1 > ul{
  justify-content: space-between;
}

#nav2 > ul > li{
  flex-grow: 1;
}

#nav3 > ul > li{
  flex-grow: 1;
  flex-basis: 0;
}

#nav4 > ul{
  justify-content: flex-start;
}
#nav4 > ul > li:last-of-type{
  margin-inline-start: auto;
}