Shrinking Footer, Header, & Hiding Vertical Scroll bar

So, I know this question has been asked hundreds of times but now its my turn to ask. How can I shrink the horrendous size of the Footer, and the Header to my Homepage? Ive tried inserting other's CSS codes into the Custom CSS space in the Design editor, but none of them seem to work. I know virtually NOTHING about CSS, except that you copy & paste some code into the box and something happens. This seems to be the only way to shrink the Footer size. 

For the Homepage at least, I want the page to be a single STILL page, no scrolling up/down or left/right. I think I can achieve that by shrinking the Footer & Header. At the same time, is the a way to essentially HIDE the vertical scroll bar from the site navigation?

Thank you so much for any suggestions, I attached a screenshot below

Hi. Can you share site url? We can help easier.