code: def addStyle(w):
      
      # access global container in root widget
      root = get_root(w)
      g = root.globals
      fsize = g.cpars['font_size']
      family = g.cpars['font_family']
  
      # Default font
      g.DEFAULT_FONT = font.nametofont("TkDefaultFont")
      g.DEFAULT_FONT.configure(size=fsize, weight='bold', family=family)
      w.option_add('*Font', g.DEFAULT_FONT)
  
      # Menu font
      g.MENU_FONT = font.nametofont("TkMenuFont")
      g.MENU_FONT.configure(family=family)
      w.option_add('*Menu.Font', g.MENU_FONT)
  
      # Entry font
      g.ENTRY_FONT = font.nametofont("TkTextFont")
      g.ENTRY_FONT.configure(size=fsize, family=family)
      w.option_add('*Entry.Font', g.ENTRY_FONT)
  
      # position and size
      # root.geometry("320x240+325+200")
  
      # Default colours. Note there is a difference between
      # specifying 'background' with a capital B or lowercase b
      w.option_add('*background', g.COL['main'])
      w.option_add('*HighlightBackground', g.COL['main'])
      w.config(background=g.COL['main'])
docs: Styles the GUI: global fonts and colours.
  
      Parameters
      ----------
      w : tkinter.tk
          widget element to style