Virtue theme shifting left, if browser scrollbars necessary

Hi,

I tried my best to find it on my own, but I can not find the cause of that behavior:
If the browser content is scrollable, then the whole layout gets shifted left. Its easy reproduceable by just changing the vertical size of the web browser. Even if a remove the complete custom css part, that strange behavior doses not change.

Appears with latest Chrome and Firefox. IE 11 and Edge are not affected:
https://www.herzenswellen.at/ueber-mich/

Thanks for any advise,
Thomas