How to reduce padding between grid galleries

I'm trying to reduce the padding between all the grid galleries under "portfolio" and was curious if anyone knew how to do it. All the padding settings under site styles seems to change everything on the site except for the galleries. Please let me know if anyone has a solution for this.

Check out the site: www.reverihomes.ca

Thanks in advance!

Sam

@chamsang add to Home > Design > Custom CSS

.homepage .sqs-block-gallery {
    padding-left: 0;
    padding-top: 0;
}
.homepage .sqs-block-gallery:nth-child(4n+1) {
    padding-right: 0;
    padding-bottom: 0;
	padding-left: 17px;
	padding-top: 17px;
}