Web pages are supposed to seem different on different platforms and such. Your job is to make it work well on all of them but you'll have to give up being a control freak. The sites that seem to stay the same, those are often the very worse. They tend to vary very little on graphical browsers but as soon as you try to use a non-graphical one they collapse.
“The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
—Tim Berners-Lee, W3C Director and inventor of the World Wide Web