Change About us background color to transparent

Im just trying out some things with your Illdy theme and like the potential it has but have some questions.
How can I set the background color in About Us section to transparent so you can see the jumbotron background image? I like how the first top section has the content scroll over top the background image. But the following sections, about us, testimonials, projects, etc all have colors or images so when they scroll up it covers the background jumbotron image.

I would like the jumbotron background image to be seen behind all other sections. Can this be done? Thank you for any help with this. Im excited to see if i can get whats in my head into this theme display.

2 other things.

1 - How can I center the top menu navigation? Why is it off center?

2- The Services, Team, Contact Us and footer widgets do not show up on mobile display.

3- I added an image to About Us widget using custom html. Image shows up fine but its not responsive. ???

I give up for today. Terribly frustrated.