eliminate the gaps between sections in V 7.1

How can I eliminate the gaps between 2 sections in 7.1?

What do you mean? Can you share a screenshot of the problem?

Set the section height to 10 in the section settings.

If you want to remove all gap between sections, add this to Home > Design > Custom CSS

#page section .content-wrapper {
	padding-top: 5px !important;
	padding-bottom: 5px !important;
}