title: How to add a border color to a button in tkinter python3
body: <p>How do I set the border color (default, not if mouse is hovering above) of a button?
  I have searched the internet but found nothing.</p>
  <pre><code>from tkinter import *
  
  root = Tk()
  bindings = {
      '&lt;FocusIn&gt;': {'default': 'active'},
      '&lt;FocusOut&gt;': {'default': 'active'}
  }
  
  for k, v in bindings.items():
      root.bind_class('Button', k, lambda e, kwarg=v: e.widget.config(**kwarg))
  
  root.title('Calculator')
  root.config(bg='black')
  
  x = Button(root, text='tgrsj', padx=50, bg='black', fg='lime',
             highlightcolor=&quot;blue&quot;,
             highlightbackground=&quot;blue&quot;,
             highlightthickness=10,
             relief=SOLID).grid(row=0, column=0)
  
  root.mainloop()
  
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Kebh9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Kebh9.png" alt="here is the new image" /></a></p>