Have a image placed in header
PermalinkDo not only modify the main.css in the themes directory. If there has been done an update before you must also modify the /update/concrete5/themes/main.css file I didn´t know that, so changed did not effect the page at all before. Again thank you for your help! I believe this happens more often to users as I have found some forum entries with the same issue.
Good it worked out for you :).
the margins or padding in the header is probably set in the CSS of the template, and can not be edited by editing the inner div, unless you use -margins (margin: -20px; for an example). If you have a URL to you site I can have a quick look and work out a solution for you :).