.div-playground {
  border: 1px solid #555;
  padding: 5px;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: stretch;
  gap: 5px;
  min-height: 50px;
}

.div-playground > div {
  height: 50px;
  display: flex;
  justify-content: center;
  align-items: center;
  border: 1px solid #999;
  text-shadow: -1px 0 #fff, 0 1px #fff, 1px 0 #fff, 0 -1px #fff;
  font-weight: 700;
}