import tkinter as tk

root = tk.Tk()
# 缺少mainloop()调用

import tkinter as tk

root = tk.Tk()
root.mainloop()  # 添加主事件循环

label1.pack()
label2.grid(row=0, column=0)  # 混合使用会导致意外行为

# 统一使用pack
label1.pack()
label2.pack()

# 或统一使用grid
label1.grid(row=0, column=0)
label2.grid(row=1, column=0)

text = "初始文本"  # 普通Python变量
label = tk.Label(root, text=text)
text = "新文本"  # 不会更新标签

text_var = tk.StringVar(value="初始文本")
label = tk.Label(root, textvariable=text_var)
text_var.set("新文本")  # 会自动更新标签

def long_running_task():
    import time
    time.sleep(10)  # 阻塞主事件循环

button = tk.Button(root, text="运行", command=long_running_task)

import threading

def long_running_task():
    import time
    time.sleep(10)

button = tk.Button(root, text="运行", 
                  command=lambda: threading.Thread(target=long_running_task).start())

def calculate():
    # 复杂计算阻塞主线程
    result = sum(i*i for i in range(10**7))
    label.config(text=str(result))

button = tk.Button(root, text="计算", command=calculate)

def calculate_step(start, end, step=10000):
    total = 0
    for i in range(start, min(end, start+step)):
        total += i*i
    if end > start+step:
        root.after(10, calculate_step, start+step, end)
    else:
        label.config(text=str(total))

button = tk.Button(root, text="计算", 
                  command=lambda: calculate_step(0, 10**7))

from tkinter import ttk

style = ttk.Style()
style.configure('TButton', font=('Arial', 12))
button = ttk.Button(root, text="样式按钮")

style.theme_use('clam')  # 使用clam主题

try:
    from ctypes import windll
    windll.shcore.SetProcessDpiAwareness(1)
except:
    pass