body{
    font-family: sans-serif;
    background-color: rgb(110, 149, 165);

}
.calculator{
    width: 300px;
    height: 500px;
    background-color: rgb(22, 14, 14);
    margin: 100px auto;
    box-shadow: 0 5px 10px 0 black;
    border-radius: 10px;
}
.output{
    text-align: right;
    height: 60px;
    padding-top: 10px;
    margin: 10px 20px;
    font-size: 25px;
    color: white;
}
.keyboard{
    margin-top: 20px;
    height: 410px;
}
button{
    width: 55px;
    height: 60px;
    float: left;
    margin: 10px;
    border-radius: 50%;
    border: none;
    font-size: 20px;
    cursor: pointer;
    color: white;
}
button:active{
    font-size: 15px;
}
.operator{
    background-color: rgba(130, 128, 128, 0.735);
}
.number{
    background-color: rgba(94, 91, 91, 0.605);
}
.empty{
    background-color: rgba(94, 91, 91, 0.605);
}