Filling the screen

Some of the monitors that view my website have a resolution of 1920 X 1080. I have gotten inquires as to why there is grey space after my footer. I was under the impression that Sydney adjusted for screen size. I am trying to fix the height of the frontpage template, but I can’t find where to edit the template for this. Please help.
Thank you.

Hi,

can you post a link to your site here?