pseudoéléments
Pseudoéléments are keywords added to selectors that let you style specific parts of an element. They don't represent actual HTML elements in the document tree but are used for stylistic purposes. Common pseudoéléments include ::before and ::after, which allow you to insert content before or after the content of an element. This is often used for decorative elements, icons, or clearing floats. The ::first-line pseudoélément targets the first line of text within an element, enabling you to style it differently, for example, making it larger or bold. Similarly, ::first-letter styles the very first letter of a block of text, useful for drop caps. The ::selection pseudoélément allows you to customize the appearance of text when it is selected by the user. It's important to note the double colon syntax (::) for pseudoelements, distinguishing them from pseudo-classes which use a single colon (:). Pseudoelements are a powerful CSS tool for enhancing the visual presentation of web pages without altering the underlying HTML structure. They are widely supported by modern browsers and are an integral part of CSS styling.