Course positioning on a website browser

Hi All,

I am using AC 2017 and my project is not containing fluid boxes. I  would like to ask if anyone knows how to position a course in the middle of the website browser. So that it would be center-aligned both vertically and horizontally, not only horizontally as it is by default. In other words: how can I achieve number 2, starting from number 1:

I am not a very proficient Captivate user, and would appreciate any help with this.

Thanks,
Emilia