Problem Header

Hi,
I like your Plugin very much and wanted to use it on my new Homepage.
But my header style changes always if i use your plugin.

Normal header:

https://www.helm-test.de/wp-content/uploads/2014/05/Bildschirmfoto-2014-05-13-um-10.47.17.png

Header if using the plugin:

https://www.helm-test.de/wp-content/uploads/2014/05/Bildschirmfoto-2014-05-13-um-10.49.35.png

The header also changes on the “home” page and all “category” pages if i publish one article with the review page.

changing the width does not help.

I use the theme customizr and the problem is on every browser!

This is the page:
https://www.helm-test.de

I hope you can help me.

Sorry for bad english.

https://www.ads-software.com/plugins/wp-product-review/