In an ideal world, you would be able to maintain a consistent appearance for your web pages regardless of the browser used to view them. Unfortunately, it's not an ideal world. The best that can be hoped for is a high degree of consistency, with graceful degradation where that is not possible.
One of the best ways to approach creating a site that works well across platforms is to respect best practices in coding and to strive to write code that is standards compliant. The relevant standards are outlined by the World Wide Web Consortium, commonly known as the W3C. In addition to outlining the various standards, their website includes a number of resources. Visit the site at http://www.w3.org/.
There are a number of elements involved in creating web pages that comply with standards. Your best bet is to add a validator to your toolkit. Be sure to validate both the CSS and the HTML in your theme. In the next section of this chapter, we discuss several...