/* PREVIEW 1 */
.preview1 {
    min-height: 25vh;
}

.preview1 .box {
  width: 100px;
  height: 100px;
  background-color: red;
}

/* PREVIEW 2 */
.preview2 {
    min-height: 25vh;
}

.preview2 .box {
  width: 100px;
  height: 100px;
  background-color: red;
  margin: 10px;
}