CSS handles the look and feel part of a web page. Using CSS, you can control the colour of the text, the style of fonts, the spacing between paragraphs, how columns are sized and laid out, what background images or colours are used, layout designs, variations in display for different devices, and screen sizes as well as a variety of other effects.
Advantages of CSS:
CSS saves time − You can write CSS once and then reuse the same sheet in multiple HTML pages. You can define a style for each HTML element and apply it to as many Web pages as you want.
Pages load faster − If you are using CSS, you do not need to write HTML tag attributes every time. Just write one CSS rule of a tag and apply it to all the occurrences of that tag. So less code means faster download times.
Easy maintenance − To make a global change, simply change the style, and all elements in all the web pages will be updated automatically.
Superior styles to HTML − CSS has a much wider array of attributes than HTML, so you can give a far better look to your HTML page in comparison to HTML attributes.
Multiple Device Compatibility − Style sheets allow content to be optimized for more than one type of device. By using the same HTML document, different versions of a website can be presented for handheld devices such as PDAs and cell phones or for printing.
Global web standards − Now HTML attributes are being deprecated and it is being recommended to use CSS. So it's a good idea to start using CSS in all the HTML pages to make them compatible with future browsers.
One of the primary advantages of CSS is that it allows developers to separate content from its presentation layer. CSS changes the traditional method of setting style and layout on each individual web page by allowing CSS designers to use a single file to control the style and layout of multiple web pages on the same website.
It is the job of CSS to define the styles of the HTML document. So with CSS, you have much better control over the layout of your web pages. You can specify exactly how big the font will be, exactly where an element will be on a page, what the page will look like when printed, and much more.
CSS is easy to learn and understand but it provides powerful control over the presentation of an HTML document. Most commonly, CSS is combined with the markup languages HTML or XHTML.
The main goal (as a method sheet language) was to separate document content from document presentation, which incorporates style elements, like colour, layout, and fonts. CSS handles the design and feels like a part of an internet page. Using CSS, you will control the colour of the text, the design of fonts, the spacing between paragraphs, how columns are sized and laid out, etc.