We don't provide support for third-party products but...
Use this code...
.g-content {
margin: 0;
padding: 0;
}
To create a custom CSS compatible with Gantry 5 please read this
http://docs.gantry.org/gantry5/tutorials/adding-a-custom-style-sheet
.
Remember to recompile CSS from base outline too.
Regards, Mark.