I am working on a tkinter python app using ttkbootstrap to have better styling and am trying to use round toggle check buttons to make it look nicer. By default these have a smaller font size than what I have been using for the rest of the app, and I want to increase it.

I tried the code below to change the font size of all round toggle tool buttons in my code but instead it cause my object to turn into just text of that font without the actual toggle showing up. How can I fix this so it works as intended?

import tkinter as tk
import ttkbootstrap as tb

root = tb.Window(themename="superhero", title="NuMercy Functions")
root.state("zoomed")
tb.Style().configure('Roundtoggle.Toolbutton', font=(FONT, 16))

autosave_state = tk.BooleanVar(value=True)
autosave_checkbox = tb.Checkbutton(root, style="Roundtoggle.Toolbutton", text="Autosave", variable=autosave_state)
autosave_checkbox.pack()