body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: aqua;  
}

.calculator{
    width: 30%;
}

.screen{
    background-color: beige;
    height: 2rem;
    display: flex;
    justify-content: right;
    padding-right: 5px;
    align-items: center;
}

.buttons{
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
}

.buttons button{
    height: 2rem;
}