Removing light grey borders around content in 'able'

Hello,
The Able theme is fantastic and very easy to use plus there’s great support on these forums to help me with it.

However, I am not sure what CSS code to write in my child-theme to remove the light grey borders that appear around the main content areas on each ‘page’ and ‘post’.
I found the solution in wordpress.com which was:
.hentry {
border: none;
box-shadow: none;
}
But this doesn’t work on the .org version of the same theme.
Does anyone have any ideas please?
Jahn