The CSS :hover selector is one of many pseudo-classes that are used to style elements. :hover is used to select elements that users hover their cursor or mouse over. It can be used on all elements, not only on links.

When used to style links, :hover is often paired with the :link, :visited, and :active selectors which style unvisited, visited, and active links, respectively.

If :link and :visited rules are in the CSS definition, :hover should fall after them. Otherwise, the styles in the :hover rule won't be applied to the selected element.

Syntax:

a:hover {
  /* CSS declarations */
}

The hover selector only applies the styles provided in the rule when an element enters the hover state. This is typically when a user hovers over the element with their mouse.

button {
  color: white;
  background-color: green;
}

button:hover {
  background-color: white;
  border: 2px solid green;
  color: green;
}

In the example above, the button’s normal styling is white text on a green button. When a user hovers over the button with their mouse, the rule with the :hover selector will become active and the button’s style will change.

Note that :hover can be problematic on touchscreens – different hardware and mobile browser implementations can cause the pseudo-class to be triggered in some cases and not in others. Make sure to thoroughly test elements with :hover in as many different mobile browsers and devices as possible.