What is the primary function of CSS in web design?

The primary function of CSS, or Cascading Style Sheets, in web design is to control the presentation and layout of web pages. CSS allows designers and developers to separate the content of a webpage (which is typically structured using HTML) from its visual appearance. This separation enables greater flexibility and efficiency in web design.

Using CSS, designers can specify styles for various elements on a page, including font styles, colors, spacing, positioning, and responsive layouts for different screen sizes. The ability to apply styles globally across multiple pages by linking a single CSS file promotes consistency throughout the site and simplifies maintenance, since changes can be made in one location rather than throughout all HTML files.

The other choices refer to aspects not directly related to CSS's function. The structure of web content is primarily defined through HTML. Server-side scripting involves programming languages like PHP or Python, which execute on the server to generate dynamic web content. Database creation is related to back-end development, typically using database management systems, rather than CSS, which is strictly focused on style and layout.