border showing in chrome when targeted.

Hi

I have a small issue with my website, when you click on the call to action button on the landing page, it scrolls down to the main menu.

However in chrome there is a blue line which looks like a border which appears around the navigation section. It is only visible until the screen is clicked, then it disappears. I can’t locate which element is being effected, and figure out how to stop this happening.

The site is curtiswebsitedesign.com

Thanks