Tham khảo tài liệu 'build a better website 2010 phần 5', công nghệ thông tin, đồ họa - thiết kế - flash phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | USING CSS CSS code is infinitely flexible allowing you to define how elements - such as links using the a tag pictures using the img tag or headings using the hl tag - look across an entire website. Alternatively you can give each element a unique name and assign it an individual style hat doesn t appear anywhere else on your site. Although you can write the css code directly into your page the real benefit comes in separating it into a file of its own. With the Style information separated from the content you can focus your attention on producing excellent copy for your visitors to read when working with the pages themselves and switch to a more visual mindset when it comes to defining the layout. When you separate css in this way you call it into each page with a single line of code in the head section. This means you can create a single stylesheet for your entire site to which each page refers in turn. The benefit is obvious by centralising your Style and layout information in a single file that all your pages use as a resource you can make radical site-wide changes simply by editing the stylesheet rather than having to change even individual page on your site. As a result you will spend less time working on the code for each page and reduce the chance of introducing errors in the process. Professional web designers use css widely and if you re serious about developing your website you should make the effort to learn at least the basics. Fortunately you don t need to do this wholesale from day one. As we explained on page 51 browsers are a perfect example of how all software should handle backwards-compatibility as they are happy to mix 10-year-old code with the latest css mark-up. When you start using css to Style your layouts we recommend that you use layers rather than tables and if you wish stick with the HTML formatting tags we defined in the previous section before moving on from there. We also recommend that you work with elements that already exist .
