body {
    font-family: sans-serif;
    background: whitesmoke;
}

h1 {
    font-size: 30px;
    color: blueviolet;
    text-align: center;
}

input[type=number] {
  width: 300px;
  font-size: 1rem;
}

input[type="button"] {
    border: 0;
    background: whitesmoke;
    display: block;
    margin: 20px auto;
    border: 5px solid rebeccapurple;
    padding: 15px 10px;
    width: 200px;
    outline: none;
    color: blueviolet;
    border-radius: 25px;
    transition: 0.25s;
    text-align: center;
    cursor: pointer;
}