What we will cover in this article more specifically is the subject of pseudo-classes! First of all, what pseudo-classes are, you may ask. They are keyword in CSS language that lets you interact with external factors or events, like moving the mouse over an element or visiting a link. We will not cover here all the pseudo-classes but after reading this article you will get the idea! The main idea behind this pseudo-classes is that they expose events in CSS language witch means that is easier to interact with HTML element on web pages.