Help, the Auto Top Margin is not working as intended. Need for it to knock my footer down to the bottom

I am trying to set my Body (All Pages) tag to flex and to vertical. Does it without any issue. I then select my footer section and set the top margin to auto. Absolutely nothing is happening and I still have this huge white blank section at the bottom of my site. Please help!

If anyone has trouble with what I created as a topic (regarding visibility), please let me know I need to solve this asap

Site: peachbuilders.co
PW: mfjovy20![Screen Shot 2020-11-04 at 8.25.32 PM|690x322]
(upload://zwNJ079qnWGF7ls47Qy0lJCfL4U.png)


Here is my site Read-Only: LINK
(how to share your site Read-Only link)

PW: mfjovy20

Idk why it is coming out the way it is in the forum.

Here is a screenshot to show that I have indeed set my body all pages tag to flex;vertical