h1 {
  text-decoration: underline;
}


.display {
    border: 1px solid black;
    font-family: Monospace;
    font-size: 2.5rem;
    line-height: 3rem;
    text-align: right;
    width: 20rem;
    height: 3rem;
}

.history {
    font-size: 1.5rem;
    width: 20rem;
    text-align: right;
    height: 2rem;
}

.button {
    width: 5rem;
    height: 5rem;
}