<div></div>
<div></div>

<hr>

<div></div><div></div>

* {
  background: #f1f1f1;
}

div {
  display: inline-block;
  width: 200px;
  height: 100px;
  background: #212a34;
}

div:nth-child(even) {
  background: tomato;
}

hr {
  border: none;
  height: 1px;
  background: lightgray;
  margin: 20px 0;
}