Setting the the resolution of the browser window for learner

Hi,

I have a seemingly simple question but I can´t find the answer.

We have a responsive project in CP9 and want it to open in the a browser window (once started from an LMS) as default in a resolution of 1080 by 720.

I know that the resolution scales depending on break points but I am referring to the size of the first pop-up tab the learners see.

How do I set that resolution? I don´t want to tell them "please go to full screen" etc.

There has to be a setting somewhere...

Thanks a lot!