I did not changed any of the Nucleus css files. I also inspect that margin and padding on g-container are not present.
For css I have created custom style-sheet in custom directory.
Screenshot for Hydrogen Settings:
https://awesomescreenshot.com/0d95dq4l03
Because of this issue I have updated G5 framework, but still this issue exist there.
How do I update the theme? Will updating hydrogen theme affect all my saved changes/layouts?