Changing opacity on a single banner?

I looked around on Answers and wasn't able to find an answer. I'm looking to add an overlay to the banner on this page only.

https://craftingyourpath.squarespace.com/about

Can anyone help, please?

@ineedhelpwithmysite Add to Home > Design > Custom CSS

section#cyp:after {
   content: "";
   background: rgba(0,0,0,0.5);
   position: absolute;
   top: 0;
   left: 0;
   right: 0;
   bottom: 0;
}

@tuanphan Worked wonderfully! Thank you so much.