What language is primarily used for styling web pages?

The primary language used for styling web pages is CSS, which stands for Cascading Style Sheets. CSS is specifically designed to control the layout, presentation, and visual aesthetics of web pages. It allows developers to apply styles such as colors, fonts, spacing, and positioning to HTML elements, enhancing the overall user experience and design consistency across a website.

In contrast, JavaScript is a programming language used for adding interactivity and dynamic behavior to web pages but is not focused on styling. HTML, or Hypertext Markup Language, is the standard markup language used to create the structure of web pages but does not involve styling itself; instead, it provides the content and structure that CSS styles. PHP is a server-side scripting language primarily used for web development and back-end processing, not specifically for styling purposes.

Thus, CSS is the go-to language for web designers and developers when it comes to defining the look and feel of a web page.