Wordpress CSS Fix

I have a problem with new Wordpress themes. I currently use an old theme and have integrated into it my custom HTML into the header and footer and it works. If I want to use any new theme my HTML in the header, is broken. It contains a table with fixed 80 px height and for some reason WordPress make this 87 px leaving the background visual. This is very annoying and I don´t want to investigate what is causing this anymore (which is not caused in my old theme). I currently integrated this into Suffusion theme and everything is already done just this annoying bug which I cannot fix. I need someone to check the CSS or code into what is causing this and fix it. I also want the person to make this header fluid. It already expands correctly, but it does not collapse to well, it breaks at less than 800 resolution, I can show you one part where I already have it running in a fluid mode. So this is basically just fix the Table or CSS code and make it fluid like in a page I already have. There is no design or coding to be made, everything is done, just check what is wrong and tell me the adjustments. Files will be send on project accepted and I tester has to have his own Wordpress install if he wants to test this offline. It should not take more than 20 minutes to find the CSS bug or see why the tables are being re-sized by Wordpress. Making fluid is just copying the code I will show you on a page and adjust it to the wordpress header.