I am testing a WP install along with a custom theme made by third parties. The theme per se is responsive, however in some situations, at particular resolutions, parts of the page will be blank although it looks like there would be enough space to fit objects. For instance take a look here (the 3 columns below the main slider) and using Chrome Dev Tools, you will see that switching to mobile view and shrinking the window, at 780px the browser will adjust page showing only one column on the left, leaving a large amount of blank space.
I am wondering if there are some Wordpress-related settings or it is just a matter of CSS?