Page shifts 10px

I’m currently incorporating WP into my website. When one of my pages (even using the very same template) gets longer than a certain length, e.g. because of posts, the whole framework shifts exactly 10px to the left. Changing the page back to a shorter one will shift the page 10px to the right. See developer.silvercorn.com for an example of this.

I have tried my best to resolve this without success. I would be most grateful for any tips that can shed some light on this annoying issue.

Thanks and best regards, Christian