from tkinter import *
root = Tk()
root.geometry("300x300")
root.resizable(0, 0)
root.config(bg="#116363")
root.title("Reversão do IVA")
titulo = Label(text="Reversão do IVA",
               font=("Arial", "25", "bold"),bg="#116363",fg="#35f2f2")
titulo.place(relx=0.05, rely=0.05)
texto_sub1  = Label(text="Preço:",
                    font=("Arial", "12", "bold"),bg="#116363",fg="#35f2f2")
texto_sub1.place(relx=0.2, rely=0.25)
Preço = DoubleVar()
Preço_entrada = Entry(textvariable=Preço,
                             font=("Arial", "12", "bold"),
                             bg="white", fg="blue", justify='center')
Preço_entrada.place(relx=0.5, rely=0.25, relwidth=0.35)
def app():
    p = Preço.get()
    pcomiva = p*1.06
    mensagem = f"Preço com IVA a 6%: {round(pcomiva,2)}"
    resultado.set(mensagem)
def limpar():
    Preço_entrada.delete(0, END)
    resultado.set("")

but1 = Button(text="Calcular", bd=2, bg='#107db2', fg='white',
              font=('verdana', 12, 'bold'), command=app)
but1.place(relx=0.05, rely=0.45, relwidth=0.25, relheight=0.1)
but_limpar = Button(text="Limpar", bd=2, bg='#107db2', fg='white',
                    font=('verdana', 12, 'bold'), command=limpar)
but_limpar.place(relx=0.35, rely=0.45, relwidth=0.25, relheight=0.1)

but_sair = Button(text="Sair", bd=2, bg='#107db2', fg='white',
                    font=('verdana', 12, 'bold'), command=root.destroy)
but_sair.place(relx=0.65, rely=0.45, relwidth=0.25, relheight=0.1)

resultado = StringVar()
resultado_texto = Label(textvariable=resultado,
                           font=("Arial", 12, "bold"), bg="#cfe2f3")
resultado_texto.place(relx=0.05, rely=0.6, relwidth=0.9,relheight=0.3)
root.mainloop()