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

html{
    font-size: 10px;
    font-family: Arial, Helvetica, sans-serif;
}

body{
    background-color: lightgray;
}

.base{
    margin: 125px auto;
    padding: 20px;
    width: 300px;
    height: 400px;
    background-color: gray;
    border-radius: 10px;
    box-shadow: rgb(97, 97, 97) 6px 6px 0px;
}

.display{
    display: flex;
    justify-content: end;
    overflow: hidden;
    padding: 10px;
    align-items: center;
    width: 100%;
    height: 40px;
    background-color: lightgray;
    border-radius: 5px;
    margin-top: 20px;
    margin-bottom: 30px;
    font-size: 2rem;
}

.keyboard-grid{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(5, 1fr);
    gap: 5px;
}

.keyboard-grid > button{
    height: 50px;
    text-align: center;
    border-radius: 5px;
    font-size: 2rem;
}

.keyboard-grid > .span-two{
    grid-column: span 2;
}

.keyboard-grid > .operator{
    background-color: rgb(255, 200, 98);
}