style.css

*{
    box-sizing: border-box;
}
body {
    padding: 0;
    margin: 0;
}
.calc{
    width: 300px;
    padding: 0;
    margin: 0;
}
.display{
    color: white;
    background-color: black;
    text-align: right;
    padding: 5px 5px;
    font-size: 30px;
}
.calc-button{
    width: 24%;
    height: 60px;
    padding: 15px;
    border: none;
    border-radius: 5px;
    font-size: 17px;
    background-color: rgb(172, 169, 169);
    cursor: pointer;
}
.calc-button:hover{
    background-color: rgb(212, 208, 208);
}


.calc-button:active {
    background-color: #bbbcbe;
}

.calc-button:last-child {
    background-color: #df974c;
    color: white;
}

.calc-button:last-child:hover {
    background-color: #dfb07e;   
}
.calc-button:last-child:active {
    background-color: #dd8d37;
}
.double {
    width: 49.3%;
}
.calc-row {
    align-content: stretch;
    justify-content: space-between;
    margin-bottom: 0.5%;
    
}