How do I change background colour of a button on hover in Tkinter?

Question

I want to change my background and foreground colour of a button on mouse cursor hover in the Python Tkinter module. I am able to change the background colour of the button once before packing it to the main window. But after the window.mainloop() line I cannot execute anymore line until the main window destroyed (or closed).

I am asking that is there any way to change the button colour (background and foreground) on mouse hover even after the window.mainloop() line?

My code

import tkinter

window = tkinter.Tk()
button = tkinter.Button(window, text="Test", fg='#03045e', command=terminate_instant,
                        relief=tkinter.RIDGE, bg='#caf0f8', activebackground='#ef233c',
                        activeforeground='white')
button.pack(side=tkinter.BOTTOM)
window.mainloop()

Answer 1

You can use <Enter> and <Leave> events to change the fg and bg color of the button:

import tkinter

window = tkinter.Tk()
button = tkinter.Button(window, text="Test", fg='#03045e', command=terminate_instant,
                        relief=tkinter.RIDGE, bg='#caf0f8', activebackground='#ef233c',
                        activeforeground='white')
button.pack(side=tkinter.BOTTOM)
button.bind("<Enter>", lambda e: button.config(fg='#caf0f8', bg='#03045e'))
button.bind("<Leave>", lambda e: button.config(fg='#03045e', bg='#caf0f8'))
window.mainloop()