CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of structured documents (such as HTML pages). The CSS specifications are developed by the World Wide Web Consortium (W3C). CSS has evolved over several versions with CSS3 being the latest. CSS3 introduces new modules that extend formatting to include features like rounded corners, shadows, gradients, transitions and animations. CSS provides control over text styling, spacing, alignment, sizing and positioning of elements and more.