* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }

.casing{
    background-color: aqua;
    border-color: black;
    padding: 12px;
    width: 140px;
    height: 140px;
}
.screen{
    background-color: white;
}

button{
    /* button no need to put .nani2 */
    margin: 1px;
    height: 20px;
    width: 24px;
}

.numberSet{
    margin-top: 3px;
    padding: 0;
}

.number{
    margin: 0;
    padding: 0;
    height: fit-content;
    width: fit-content;
}

.calculationOperations{
    margin-top: 3px;
}

#showScreen{ 
    /* id need to adjust using # */
    width: 115px;
}