div {
  width: 250px;
  height: 100px;
  border: 5px solid #000000;
  color: black;
  font-weight: bold;
  text-align: center;
}

div #d1 {
  background-color: red;
  margin: 15px;
}

div #d2 {
  background-color: green;
  margin: 15px;
}

div #d3 {
  background-color: blue;
  margin: 15px;
}

div #d4 {
  background-color: yellow;
  margin: 15px;
}