Hi Mohamed,
Thank you for your question and thanks for using BoldGrid Post and Page builder for WordPress!
I think you may just need to adjust your header elements margin or padding to make it smaller. You have your site set to maintenance mode at the moment so I can’t tell you exactly what to do. If you could remove maintenance mode and send us the URL where you would like us to review we can let you know what needs to be done.
If you’re using Crio Pro WordPress Theme you can follow this guide, to help you learn how to better work with headers.
I hope this helps!