body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    color: white;
    background-color: black;
    font-family: Arial, sans-serif;
}

.container {
    padding: 20px;
}

.fizzbuzz pre {
    white-space: pre-wrap;
}

.rules h2 {
    margin-top: 20px;
}

.rules ul {
    padding-left: 20px;
}