ttkでボタンのテキストカラーを変更したい

Question

概要

Tkinterを使って、○✖️ゲームを作っています。
勝敗がついたら、揃ったマークの色が変わり、ゲーム終了となります。

上画像の場合では、斜めの○が揃っているので、この3つの○の色を赤色にしたいのですが、変更されませんでした。
何故うまく変更されないのかわからないため、教えていただきたいです。

ソースコード

from tkinter import *
from tkinter import ttk


class MyGame(ttk.Frame):

  SETTLEMENT_PATERN = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6]
  ]

  def __init__(self, master=None):
    super().__init__(master)
    master.title('課題04_01')
    master.columnconfigure(0, weight=1)
    master.rowconfigure(0, weight=1)

    self.style = ttk.Style()
    self.style.configure("Red.TButton", foreground="red")

    self["padding"] = 10
    self.grid(sticky=(E, W, S, N))
    self.columnconfigure(0, weight=1)
    self.rowconfigure(0, weight=1)

    self.label1 = ttk.Label(self, text="○のターンです")
    self.label1.grid(row=0, column=0, columnspan=3, stick=(N, S))

    self.button00 = ttk.Button(self, padding=5)
    self.button00["command"] = lambda: self.set_text2b(self.button00)
    self.button00.grid(row=1, column=0, stick=(E, W, S, N))
    self.button01 = ttk.Button(self, padding=5)
    self.button01["command"] = lambda: self.set_text2b(self.button01)
    self.button01.grid(row=1, column=1, stick=(E, W, S, N))
    self.button02 = ttk.Button(self, padding=5)
    self.button02["command"] = lambda: self.set_text2b(self.button02)
    self.button02.grid(row=1, column=2, stick=(E, W, S, N))

    self.button10 = ttk.Button(self, padding=5)
    self.button10["command"] = lambda: self.set_text2b(self.button10)
    self.button10.grid(row=2, column=0, stick=(E, W, S, N))
    self.button11 = ttk.Button(self, padding=5)
    self.button11["command"] = lambda: self.set_text2b(self.button11)
    self.button11.grid(row=2, column=1, stick=(E, W, S, N))
    self.button12 = ttk.Button(self, padding=5)
    self.button12["command"] = lambda: self.set_text2b(self.button12)
    self.button12.grid(row=2, column=2, stick=(E, W, S, N))

    self.button20 = ttk.Button(self, padding=5)
    self.button20["command"] = lambda: self.set_text2b(self.button20)
    self.button20.grid(row=3, column=0, stick=(E, W, S, N))
    self.button21 = ttk.Button(self, padding=5)
    self.button21["command"] = lambda: self.set_text2b(self.button21)
    self.button21.grid(row=3, column=1, stick=(E, W, S, N))
    self.button22 = ttk.Button(self, padding=5)
    self.button22["command"] = lambda: self.set_text2b(self.button22)
    self.button22.grid(row=3, column=2, stick=(E, W, S, N))

    self.button_array = [
      self.button00,
      self.button01,
      self.button02,
      self.button10,
      self.button11,
      self.button12,
      self.button20,
      self.button21,
      self.button22
    ]

  def set_text2b(self, btn):
    next_str = self.label1["text"][0]
    btn["text"] = next_str
    btn["state"] = "disabled"
    next_str = "×" if next_str == "○" else "○"
    for pattern in self.SETTLEMENT_PATERN:
      if self.button_array[pattern[0]]["text"] == self.button_array[pattern[1]]["text"] == self.button_array[pattern[2]]["text"]:
        if self.button_array[pattern[0]]["text"] == "○":
          self.button_array[pattern[0]].config(style="Red.TButton")
          self.button_array[pattern[1]].config(style="Red.TButton")
          self.button_array[pattern[2]].config(style="Red.TButton")
          for button in self.button_array:
            button["state"] = "disabled"
          self.label1["text"] = "○の勝利です"
          return
        elif self.button_array[pattern[0]]["text"] == "×":
          self.button_array[pattern[0]].config(style="Red.TButton")
          self.button_array[pattern[1]].config(style="Red.TButton")
          self.button_array[pattern[2]].config(style="Red.TButton")
          for button in self.button_array:
            button["state"] = "disabled"
          self.label1["text"] = "×の勝利です"
          return
    self.label1["text"] = f'{next_str}のターンです'

if __name__ == '__main__':
    root = Tk()
    app = MyGame(root)
    root.mainloop()