#parentbox {
  display: flex;
  flex-direction: row-reverse;
}
#parentbox > div {
  height: 145px;
  margin: 5px;
  background-color: #CCCCCC;
}
#box-1 {
  flex: 1;
}
#box-2 {
  flex: 1;
}
#box-3 {
  flex: 1;
}
#box-4 {
  flex: 1;
}