Welcome to the amazing world of web development.
Since you have not provided any code or screenshots,I cannot suggest you a guarenteed fix for your issues. So I will try to transfer myself to your machine via teleportation and will have a look at the code. But since this is the weekend , I am a bit lazy now.
Till then I am providing some generic solutions to write browser compatible CSShttp://www.iangraham.org/books/xhtml2/exerpt/css-4a.html
Hope this helps.