One of the most fundamental aspects of CSS is understanding how to use selectors effectively. A CSS selector is part of a CSS rule set that selects the content you want to style. There are five main types of selectors: Element Selector: This targets HTML elements to style. ID Selector: This is unique within a page and is used to select a single element. Class Selector: This targets multiple elements that share the same class attribute. Universal Selector: This targets all elements on a page. Group Selector: This targets multiple selectors and applies the same styles. Enrolling in an HTML training course provides students with the opportunity to delve into the fundamental aspects of CSS, including the effective use of selectors. Understanding the various types of selectors, such as the element, ID, class, universal, and group selectors, is essential for precise and targeted styling.  By mastering selector usage, students gain the skills to create visually appealing and well-structured web pages that make an impact.