* {
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
}

header {
    background-color: blue;
    color: white;
    font-size: 1rem;
    padding: 1rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

.calculator {
    padding-top: 5rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

input {
    padding: 0.5rem 1rem;
    border-radius: 7px;;
    border-color: rgba(0, 0, 0, 0.2);
}

#buttons {
    padding-top: 1.5rem;
    display: flex;
    justify-content: space-between;
}

button {
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 7px;
    cursor: pointer;
    background-color: blue;
    color: white;
}