def _df_to_html(df):
    """Converts DataFrame to HTML table with classes for formatting.

    Parameters
    ---------------
    df : pandas.DataFrame

    Returns
    ---------------
    str
        HTML table for display.
    """
    classes = ['table', 'table-hover']
    html_raw = '<div id="config_table">{src}</div>'
    src = df.to_html(index=False,
                     classes=classes,
                     justify='center',
                     escape=False)
    html = html_raw.format(src=src)
    return html