<ul class='posts'>
  <li class='post'>
    <h2>Post Title</h2>
  </li>
  <li class='post'>
    <h2>Post Title</h2>
  </li>
  <li class='post'>
    <h2>Post Title</h2>
  </li>
</ul>

.posts {
  list-style: none;
  margin: 0;
  padding: 20px;
  max-width: 650px;
  margin: 4rem auto;
  background: #f8f8f8;
}

.post {
  color: red;
}

.post:not(:last-of-type) {
  border-bottom: 1px solid #eee;
  margin-bottom: .5rem;
  padding-bottom: .5rem;
}
body{margin:30px;}