Preventing “double” borders in CSS

Question

Say I have two divs next to each other (take https://chrome.google.com/webstore/category/home as reference) with a border.

Is there a way (preferably a CSS trick) to

Answer 1

Add the following CSS to the div on the right:

position: relative;
left: -1px; /* your border-width times -1 */

Or just remove one of the borders.