What are the functions of CSS?

CSS is used to style HTML (and other markup languages) pages. The browser looks at the rules declared in CSS and applies those rules to the relevant HTML elements that it finds in the web page it is rendering. These rules can affect what font typeface is used, what size the font should be, the color of the font, background colors, the alignment of text, placement of images, text, and other items on the web page, and more.