The pseudo-classes property is used to add special effects to some selectors. This property can be used mainly to:
 Style an element when a user mouses over it.
 Style visited and unvisited links differently.
Using the :link pseudo-class on a link <a> element to change color.
a:link {
  color: blue;
}
        
        
    
        
        
            Using the :hover pseudo-class on a link<a> element to change color.
a:hover {
  color: green;
}
        
        
    
        
        
            Using the :visited link pseudo-class on a link<a> element to change color.
a:visited link {
  color: green;
}
        
        
    
    
selector:pseudo-class {
  property: value;
}
    
    Pseudo-class are different from CSS classes but they can be combined.Pseudo-classes help you cut down on excess classes in your markup.For more information, see http://www.w3schools.com/Css/css_pseudo_classes.asp
Found a bug in the documentation? Let us know at documentation@code.org