article {
  width: 720px;
  margin: 10px 0;
}
article h4 {
  margin: 0;
  padding: 5px 0;
  font-size: 1em;
  background-color: #e0ffe0;
}
article p {
  margin: 10px 0 10px 40px;
}

@media (max-width: 640px) {
  article {
    width: 100%;
  }
}