Page Height Issue

Im trying to create a website where each page has a different height depending on the length of information displayed. So far I have a fixed height in my style sheet that goes for every page, but it looks bad on the homepage for example where there is less content, giving lots of empty space at the bottom.

Im thinking is there a way of making the footer attached to the bottom of the last post? How does normal blogs work?

Here is a link to the website, https://www.flexhk.com/wordpress

any help would be very much appreciated!