Interface size

Hi ^^

This is more of a technical issue. My screen is 15.6" and in the video options I set the max possible resolution (1366*768 32-bit), but the user interface takes a large portion of the screen (around 30-40%)

Is it possible to set it so the interface looks smaller? Or is it only possible with a bigger screen?
Something like this: (please ignore the content, I only care about the interface size)

https://www.youtube.com/watch?v=goJXKCRS7S8

Thanks