from tkinter import *
root = Tk()
root.geometry("400x400")
root.resizable(0, 0)
root.config(bg="#093670")
root.title("Peso Corporal")
titulo = Label(text="Peso Corporal",
               font=("Arial", "40", "bold"),bg="#093670",fg="#05edca")
titulo.place(relx=0.05, rely=0.05)
texto_sub1  = Label(text="Massa (em kg):",
                    font=("Arial", "18", "bold"),bg="#093670",fg="#05edca")
texto_sub1.place(relx=0.05, rely=0.35)

Massa = DoubleVar()
Massa_entrada = Entry(textvariable=Massa,
                             font=("Arial", "12", "bold"),
                             bg="white", fg="blue", justify='center')
Massa_entrada.place(relx=0.55, rely=0.36, relwidth=0.35)
def limpar():
    Massa_entrada.delete(0, END)
    resultado.set("")

def app():
    m = Massa.get()
    aceleracao_gravidade = 9.81
    peso = m * aceleracao_gravidade
    pesoarr = round(peso,2)
    mensagem = f"Seu peso corporal é de {pesoarr} Newtons."
    resultado.set(mensagem)
but1 = Button(text="Verificar", bd=2, bg='#107db2', fg='white',
              font=('verdana', 12, 'bold'), command=app)
but1.place(relx=0.05, rely=0.55, 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=0.55, 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=0.55, 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=0.7, relwidth=0.9,relheight=0.25)
root.mainloop()