If I impement the Facebook comments using a lower width (in this case 380px) the content is somehow broken.
Since no custom-css is possible anymore I don't know how to fix this.
Anybody?
here is a screenshot:
This isn't something you can "fix" since you have no control over content of comments plugin frame.
Actually this is well known and documented behavior, according to documentation:
width - the width of the plugin in pixels. Minimum recommended width: 400px.