What is the main purpose of CSS in web development?

The main purpose of CSS, or Cascading Style Sheets, in web development is to design and layout web pages. CSS is specifically utilized to control the presentation aspect of a web application, enabling developers to create visually appealing styles and layouts. It allows for the customization of typography, colors, spacing, and overall design of HTML elements, which ultimately enhances the user experience. With CSS, developers can implement responsive designs that adapt to different screen sizes, ensuring that the web content looks good on various devices.

The option focused on adding interactivity addresses aspects typically managed by JavaScript, which is a separate programming language used for implementing dynamic features on web pages. Structuring web pages is primarily the role of HTML, the standard markup language for creating web content, while the storage of data securely generally falls under the realm of backend technologies and databases, rather than CSS, which deals exclusively with styling.