Reduce space between site identity and Main Menu and…

I recently upgraded to Catch Inspire Pro. Great theme! However, I struggle to figure out how to write CSS to change some attributes. Right now, I want to close the space between the Site Identity content and the Main Menu. And, I want to close the space after the main menu and the Featured Content media on my homepage. The site is: https://www.michaeldmullen.com/. The Featured Content section is title Areas of Expertise. Thanks, MM