Changing menu column width in Highend

Hi, I am using WP v4.8 and Highend 3.3.9. I want to reduce the width of the menu columns. I’ve looked at the help documentation but can’t find anything on changing column width.

I have created a menu for my blog and used the following CSS code to create a two column menu (megamenu columns-2). I want to reduce the width of the columns as they are too wide with too much padding. Can I do this?

David