How to center Collection items in Grid layout?

Seems like a simple thing.

How can I center collection items in grid layout? The collection list is located on a collection page and sometimes it has one item and sometimes more, but now the item/s align left. I would like to stay in the center.

The brown box with Johannes should be centered below the heading.:arrow_up_small:
sometimes Johannes has one colleague and they should both be centered.
Only when there’s three of them it works great…

Anyone know how to achieve this?

Here is my site Read-Only:

Here you can see the issue: