Style sheets can be a very powerful tool in web design. There are many benefits to using CSS for your web pages, as compared to using the old style table based, font-tag using, techniques. To see exactly what the appeal is to using CSS and XHTML to design your website you must first understand what the shortcomings are to using table based HTML designs.
The most obvious problem with them is the terrible bloating of the code. Tables were created as a way to present tabular data. Using them to make layouts was an afterthought, therefore tables aren’t optimized for laying out websites. Most sites that use tables for layouts end up having tables within tables within tables, and so on. A site of any significant size will soon become huge, just with embedded tables. Add to that the use of spacer gifs and deprecated font tags and your websites become server hogging, slow loading behemoths. Search engine optimization can also be affected, because most search engines only read a certain amount of each page.
Using CSS for fonts, links, hover effects and other stuff like that is a no-brainer. It has become the standard way to do things. And CSS layouts will soon be the standard way to lay pages out. The logic behind a CSS file is simple. You are meant to be able to control the attributes of every single element on a page. The format is like this:
Element{attribute: value;}
An actual example would go like this:
p{font-size: 10px;}
This 1 line of code in a CSS file will affect every single page on the website. Every <p> tag will now have a font-size specified to 10 pixels. This saves a lot of space already. In the old-style font tags you would have to have a <font> tag for every different tag. Using this same logic you could change a link color, or a table border, or the font-weight of a heading. Anything can be changed. And more attributes that can be changed will be added in future versions of CSS.
The goal of the W3C(the standards creators) is to completely separate structure from content. So, as a designer using CSS, your ultimate goal should be to put any element structure and element attribute information in the CSS file and put all the content in the html page. Just making these basic changes could save up to 300% in file size.
Any new web designer or web developer should take the time to learn the ins and outs of CSS and XHTML 1.0. For the first time in web design history, it seems, most browsers will actually adopt this standard, in current and future versions. Anybody who has been making websites for a while will appreciate the ability to make 1 version of a site instead of creating multiple versions for older browsers, or even new browsers which read your code differently. This is surely a huge step forward for the net and it’s best that you take the step too.