CSS Pseudo-elements
A CSS pseudo-element is used to style specified parts of an element. For example, it can be used to: Style the first letter, or line, of an element Insert content before, or after, the content of an element The syntax of pseudo-elements: The ::first-line pseudo-element is used to add a special style to the first line of a text.
https://www.w3schools.com/css/css_pseudo_elements.asp