CSS is an acronym for Cascading Style Sheets, a language used to describe the formatting of a document written in a markup language. In more simple words, CSS is used for adding style (fonts, colors, spacing...) to web documents. It can be applied to a variety of XML documents, from HTML and XHTML to SVG and XUL. It offers exciting possibilities to create impact with a design.
The modular structure of CSS3 allows developers to build content-rich web pages with relatively lightweight code requirements. More striking visual effects, better user interfaces and cleaner pages that load faster can be achieved more easily than ever before with CSS3. One handicap that appears when using CSS3 is the requirement to implement filters to ensure a website will look the same using different browsers. However, CSS3 can still be incorrectly interpreted by Firefox or Chrome.