body {
    font-family: Arial, sans-serif;
    margin: 20px;
}

button {
    margin-left: 8px;
    cursor: pointer;
}

#treeContainer div {
    margin-top: 5px;
}

pre {
    background: #f4f4f4;
    padding: 10px;
    white-space: pre-wrap;
}