body{
    background-color: #1c2323; 
}
.calculator {
    background-color: darkgray;
    width: 400px;
    height: 400px;
    margin: auto;
    padding: 10px;
    border-radius: 1em;
    margin-top: 100px;
}
.display-box {
    border: solid black 0.5px;
    width: 100%;
    height: 65%;    
}
#btn {
    background-color: red;
}
#result {
    font-family:'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    font-size: 2rem;
    color: black;
    padding-left: 10px;
}
input[type=button] {
    background-color: grey;
    border: solid black 0.5px;
    width: 100%;
    height: 70%;
    outline:none;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    font-weight: normal;
    font-size: 2rem;
}