Haz un diseño minimalista de los botones y la pantalla de una calculadora

from tkinter import *

root = Tk()
root.title("Calculator")
bttn_list = [
"7", "8", "9", "+", "*", 
"4", "5", "6", "-", "/", 
"1", "2", "3",  "=", "x²",
"0", ".", "C",  "±", "√"
]

r = 1
c = 0

for i in bttn_list:
    rel = ""
    cmd=lambda x=i: calc(x)
    ttk.Button(root, text=i, command = cmd, width = 10).grid(row=r, column = c)
    
    c += 1
    if c > 4:
        c = 0
        r += 1

def calc(key):
    global memory
    if key == "=":
        str1 = "-+0123456789.*/)("
        if calc_entry.get()[0] not in str1:
            calc_entry.