from tkinter import *
root= Tk()
root.geometry("400x400")
root.resizable(0,0)
root.configure(bg="#f8f1fe")
root.title("Consumo médio de combustível")
def app(*args):
    d = distancia.get()
    c = combustivel.get()
    consumo = d/c
    consumoarr = round(consumo,6)
    mensagem = f'O consumo médio foi de {consumoarr} km/l'
    resultado.set(mensagem)
def limpar():
        distancia_entrada.delete(0, END)
        combustivel_entrada.delete(0, END)
titulo = Label(text="Consumo médio de combustível ",bg="#f8f1fe",fg="#ba990a",
               font=("Arial","14","bold"))
titulo.place(relx=0.15,rely=0.05)
distancia = DoubleVar()
combustivel = DoubleVar()
distancia_texto= Label(text="Distância percorrida (em km) ",bg="#f8f1fe",fg="#ba990a",
               font=("Arial","12","bold"))
distancia_texto.place(relx=0.05,rely=0.3)

combustivel_texto= Label(text="Combustível Gasto ",bg="#f8f1fe",fg="#ba990a",
               font=("Arial","12","bold"))
combustivel_texto.place(relx=0.23,rely=0.45)

distancia_entrada= Entry(textvariable=distancia,
                            font=("Arial","12","bold"),
                     bg="white",fg="blue",justify='center')
distancia_entrada.place(relx=0.65,rely=0.3,relwidth=0.2)

combustivel_entrada= Entry(textvariable=combustivel,
                            font=("Arial","12","bold"),
                     bg="white",fg="blue",justify='center')
combustivel_entrada.place(relx=0.65,rely=0.45,relwidth=0.2)
#
but1 = Button( text="Calcular", bd=2, bg='#107db2', fg='white',
              font=('verdana', 12, 'bold'),command=app)
but1.place(relx=0.25, rely=0.6, 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=0.55, rely=0.6, relwidth=0.25, relheight=0.1)
resultado = StringVar()
resulatdoresultado =Label(textvariable=resultado,
                          font=("Arial",12,"bold"),bg="#f0f8ff")
resulatdoresultado.place(relx=0.1,rely=0.8,relwidth=0.7)
combustivel_entrada.focus()
root.bind("<Return>", app)
root.mainloop()