import dearpygui.dearpygui as dpg
dpg.create_context()
dpg.create_viewport(title='Custom Title', width=800, height=300)
with dpg.window(label='Main Window'):
main_txt = dpg.add_input_text()
btn = dpg.add_button(label='Start', tag=99)
dpg.setup_dearpygui()
dpg.show_viewport()
dpg.start_dearpygui()
dpg.destroy_context()