What is the purpose of CSS?

The purpose of CSS (Cascading Style Sheets) is to design web pages and add style. CSS is a stylesheet language used primarily to describe the presentation of a document written in HTML or XML. By using CSS, developers can control the layout, colors, fonts, and overall visual aesthetics of a website, ensuring that web pages are not only functional but also attractive and user-friendly. CSS allows for separation of content (HTML) from design (CSS), which provides greater flexibility and control in how web pages appear.

In contrast, other options mention functions that are not related to styling web pages. For instance, creating database systems or managing web hosting pertains to back-end development, while building server-side applications involves programming languages and frameworks that run on a server. These tasks do not involve CSS, which focuses solely on the visual presentation of web content.