Posts in grid doesn’t show properly

Hi, I really hope you can help me regarding an issue on my blog. I’m using the Clean Grid-theme, and entering the site from a browser, I have three columns of posts. When there are only two post in a row, the first post is on the left side (where it should be) while the second post is hanging somewhere between the center and the right side. This doesn’t look very good. It happens at the front page (on page 2 right now) and in every category containing two posts (ex. the category ’Moldova’). How can I stop this from happening?
Best regards, Benjamin

The page I need help with: [log in to see the link]