left and right margin for the whole website

Hello everybody,

I use the colormag theme and first of all I have to say that it is very nice to use.
But I have two little problems that someone might be able to help me with.
I would like to reduce the left and right margin of the site in a global way
so that I get less free space on the left and right side,
but without destroying the responsive character of the theme.

And I would like to reduce the height of the footer even though I set padding and margin to 0 there is still too much free space below of the text.

May someone can help me there?

Best regards
neko

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