Pro version has bigger width / smaller side margins than free version

I have just today upgraded my theme from the free version. What I see is that the general layout has much a wider content width, and smaller/narrower side margins. In the free version, the margins on the left and right side where much bigger, which looked much better. How can I get the same setting in the Pro version? My site URL is https://de-mastermind.nl/ (currently set to the Pro theme).