In which context is CSS primarily applied?

CSS, or Cascading Style Sheets, is primarily applied to enhance visual presentation on web pages. It allows developers to control the style and layout of HTML elements, providing the means to change colors, fonts, spacing, positioning, and overall aesthetics of a website. By separating content from presentation, CSS gives web designers the flexibility to create visually appealing and well-structured web layouts without altering the underlying HTML structure.

Using CSS makes it easier to maintain consistency across a website. For example, by defining styles in a single CSS file, those styles can be applied to multiple pages, thereby ensuring that they all have a cohesive look and feel while saving time and effort.

In contrast, options relating to structuring documents, enabling server-side operations, and ensuring data security pertain to different areas of web development. Structuring documents typically involves HTML, while server-side operations are managed by languages such as PHP or Node.js, and data security usually relies on HTTPS protocols, secure server configurations, and other measures rather than CSS.