Strange lines between sections

I frequently notice some rather unsightly lines between different sections and it seems to occur most clearly on retina displays. In this case I have a bloc with three columns and each column contains a simple paragraph bric with a link. You can see the lines pretty clearly from the screenshot and I wondered if there is any way to avoid this, because it looks pretty horrible.

You can see it here on a non retina display with no lines present.

Same problem here

Do you can send please the url of the page, which has this problem?

Probably some default borders being applied - try a custom class and set them to solid w/ width of 0.

I tried this but it made no difference. It’s actually something I’ve seen in Rapidweaver sites as well in the past, but not now when I checked.