What is the purpose of Cascading Style Sheets (CSS) in web development?

Cascading Style Sheets (CSS) play a crucial role in web development by providing the means to style and layout web pages. This involves defining how elements on a page should look in terms of colors, fonts, spacing, and overall layout. CSS allows developers to separate content from design, leading to cleaner and more maintainable web code.

By applying CSS, developers can control the appearance of individual elements as well as groups of elements, enabling consistent styling across multiple pages of a website. This not only improves the aesthetic quality of web applications but also enhances user experience, as users can expect a uniform look and feel on the site.

The other choices do not align with the primary function of CSS. Creating server-side scripts pertains to programming languages such as PHP or Node.js, storing database information relates to database management systems, and managing user authentication involves techniques often handled by backend services and frameworks, not by CSS.