Responsive page using CSS grid and flex.

There are some things i'm not sure about this code even though it worked. Like:

1 - I couldn't change the width of the button, it's not on the code because i tried a lot of times and it didn't work, when you open the page you can see the button is smaller than it should be.

2 - In the header session, i didn't knew how to change the height of the Huddle logo and it's always too big for the screen.

3 - In the last mobile session, there's a big space between the illustration and my title, i couldn't revert this.

This is my first challenge here and also my first page without help, i've been studying html and css for about a month now so any feedbacks are really welcome.