Removing space in various places

Hi all,

I have read other topics with a similar problem but none of the solutions work for my theme so I am hoping if any experts can help get this right with my theme.

So If you surf to the link I provided, you can see that there is extra space:
1) around the image of the vertically stacked books
2) between the vertically stacked books and the twitter feeds (i.e. space between columns)
3) above and below the four coloured boxes before the footer (the settings of the boxes don’t affect these spaces)

I have tried everything I know, and since I am new to Gutenberg, I think I am missing something as in how to remove these spaces. Could something guide me to remove them?

The page I need help with: [log in to see the link]