Fix style of html email with mixed sources

I have a service that validates html email letters. When the report is sent out, the original letter is included in this email. Sometimes this messes up the style of the report part. I want the background of the report part to always be white. No grey frame around it. That's it really! Attached is some file that should explain it to you and code you can work with. Deliver a modified version of "Source that is beeing [login to view URL]" with comments on what you have changed. Task is fulfilled if this source makes the email look as wanted when I send it. Important! I want minimal changes made! Don't rewrite the whole html structure and css etc, try and fix this by only adding an element or some attributes etc.