body{
  background-color: beige;
  justify-items: center;
  align-content: center;
}

#screen{
  display: flex;
  flex-direction: column;
  width: 100px;
  border: 2px solid black;
  margin: 5px;
  background-color: aliceblue;
}
.calculatorContainer{
  display: flex;
  flex-direction: column;
  border: 3px solid black;
  width: 120px;
  height: 150px;
}

#firstRow, #secondRow, #thirdRow, #fourthRow{
  margin: 5px;
}

button{
  width: 150;
  height: 50;
}