from tkinter import *
import datetime

root = Tk()
root.geometry("400x400")
root.resizable(0, 0)
root.config(bg="#103030")
root.title("Como Cumprimentar Agora")

titulo = Label(text="Como Cumprimentar Agora",
               font=("Arial", "20", "bold"), bg="#103030", fg="#49e3e3")
titulo.place(relx=0.05, rely=0.05)

sub1 = Label(text="Nome: ", font=("Arial", "18", "bold"), bg="#103030", fg="#49e3e3")
sub1.place(relx=0.05, rely=0.25)
nome = StringVar()
nome_entrada = Entry(textvariable=nome, font=("Arial", "12", "bold"),
                         bg="white", fg="blue", justify='center')
nome_entrada.place(relx=0.3, rely=0.26, relwidth=0.65)
nome_entrada.focus()
def limpar():
    nome_entrada.delete(0,END)
    resultado_texto.config(text="")

def app():
    hora_atual = datetime.datetime.now().hour
    n =nome.get()

    if 6 <= hora_atual < 12:
         saudacao= "Bom dia!"
    elif 12 <= hora_atual < 18:
         saudacao = "Boa tarde!"
    else:
         saudacao = "Boa noite!"

    text=f"{saudacao}.\nSr(a).{n},obrigado por ter vindo!!"
    resultado_texto.config(text=text)

but1 = Button(text="Mostrar", bd=2, bg='#107db2', fg='white',
              font=('verdana', 12, 'bold'), command=app)
but1.place(relx=0.1, rely=0.4, 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=0.4, rely=0.4, 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=0.7, rely=0.4, relwidth=0.25, relheight=0.1)

resultado_texto = Label(font=("Arial", 12, "bold"), bg="#cfe2f3")
resultado_texto.place(relx=0.05, rely=0.55, relwidth=0.9, relheight=0.38)

root.mainloop()