Tkinter Login Screen

from tkinter import *

entry_design = {
    'font': ("Helvetica", 11),
    'insertbackground': '#ccc',
    'highlightbackground': '#ccc',
    'highlightcolor': '#ccc',
    'relief': 'flat',
    'bg': 'white',
    'fg': '#333',
    'bd': 3,
    'width': 30,
}

label_design = {
    'font': ("Helvetica", 12),
    'bg': '#3d3d3d',
    'fg': '#eee'
}

login_button_design = {
    'highlightbackground': '#c0392b',
    'activebackground': '#c0392b',
    'activeforeground': 'white',
    'relief': 'flat',
    'bg': '#e74c3c',
    'fg': 'white',
    'bd': 0,
}


class LoginFrame(Frame):
    def __init__(self, master=None, *args, **kwargs):
        Frame.__init__(self, master=master, *args, **kwargs)

        self.configure(bg='#3d3d3d')
        self.configure(border=40)

        user_var = StringVar()
        pass_var = StringVar()

        user_var.set('Username')
        pass_var.set('Password')

        image = PhotoImage(file='login_2.png')

        app_image = Label(self, **label_design, image=image)
        app_image.grid(row=0, column=0, ipady=30)
        app_image.image = image

        self.user_entry = Entry(self, name='user_entry', textvariable=user_var, **entry_design)
        self.user_entry.bind('<FocusOut>', self.event_handler)
        self.user_entry.bind('<FocusIn>', self.event_handler)
        self.user_entry.grid(row=1, column=0, ipady=10)

        self.pass_entry = Entry(self, name='pass_entry', textvariable=pass_var, **entry_design)
        self.pass_entry.bind('<FocusOut>', self.event_handler)
        self.pass_entry.bind('<FocusIn>', self.event_handler)
        self.pass_entry.grid(row=2, column=0, ipady=10)

        self.info_var = StringVar()
        info_label = Label(self, textvariable=self.info_var, fg='orange')
        info_label.grid(row=3, column=0, sticky=EW, pady=5)
        info_label.configure(bg='#3d3d3d')

        login_button = Button(self, text='Login')
        login_button.grid(row=4, column=0, pady=4, sticky=E, ipadx=30, ipady=6)
        login_button.configure(command=self.check_credentials)
        login_button.configure(**login_button_design)

    def check_credentials(self):
        username = self.user_entry.get()
        password = self.user_entry.get()

        if username and password is not None or '':
            if username == 'admin' and password == 'admin':
                self.hide_login()
                return True

            self.info_var.set("Wrong username or password")
            self.after(3000, self.info_var.set, '')
            return False

    @staticmethod
    def event_handler(event):
        if str(event.type) is 'FocusIn':
            event.widget.delete(0, 'end')
            if str(event.widget).endswith('pass_entry'):
                event.widget.configure(show='*')
                return None
            return None

        if str(event.type) is 'FocusOut':
            if event.widget.get() is '':
                if str(event.widget).endswith('user_entry'):
                    event.widget.insert('end', 'Username')
                    return None

                if str(event.widget).endswith('pass_entry'):
                    event.widget.configure(show='')
                    event.widget.insert('end', 'Password')
                    return None
                return None
            return None

    def show_login(self):
        self.master.logout_button.grid_forget()
        self.grid(row=0, column=0, sticky=NS)

    def hide_login(self):
        self.master.logout_button.grid(row=0, column=0, sticky=N)
        self.grid_forget()


class MainWindow(Frame):
    def __init__(self, master=None, *args, **kwargs):
        Frame.__init__(self, master=master, *args, **kwargs)

        self.configure(bg='#3d3d3d', bd=20)

        self.loginFrame = LoginFrame(master=self)
        self.loginFrame.grid(row=0, column=0, sticky=NS)
        self.columnconfigure(0, weight=1)
        self.rowconfigure(0, weight=1)

        self.logout_button = Button(self, text='Logout')
        self.logout_button.configure(command=self.loginFrame.show_login)

        self.pack(fill='both', expand=True)


if __name__ == '__main__':
    mainWindow = MainWindow()
    mainWindow.master.title('User Manager')
    mainWindow.master.geometry('1040x580')
    mainWindow.mainloop()