CSS
CSS stands for Cascading Style Sheets. It’s a “language” for describing how a webpage should look, independent of the page’s specific content.
For example, you could provide CSS that tells the browser, “All tables on the page should include a one-pixel gray border with a shadow;” or “The text headings should use the 16-point Lucida font.” You could even describe layout: “The content area should go here and look like this; the header over here; and we need three columns.”
The same CSS code can apply to many pages across a website, ensuring a consistent look and layout.
Advantages
- Makes websites easier to modify: By describing your site’s basic appearance in a CSS file, you can change the appearance of the whole site just by altering the file. Without CSS, you would need to edit the HTML of every single page.
- Search engine friendly: CSS helps you cater to humans and search engines simultaneously—telling search engines what’s important without cluttering the page with bulky HTML code that will confuse them, while rendering the content attractively for human visitors. Without CSS what’s good for search engines can be bad for people, and vice versa.
- Improves device compatibility: With CSS, you can create a different look and feel for different devices: one for the Web, one for printouts, and one for smartphones, for instance.
Disadvantages
- Not always supported: Support for some advanced CSS features is limited on some older browsers, on some nontraditional devices (like some handheld computers), and in HTML emails.
Choosing CSS
CSS is always appropriate to use for at least part of your website’s design.
It’s possibile to use CSS to define all of the website’s design, so that the entire look and feel can be adjusted just by changing the CSS file, but this is frequently inappropriate because it’s not compatible with older browser versions.
