how to add transition in css code example

Example 1: css transition

<style>
div {
  background-color: blue;
  padding: 40px;
  color: white;
  cursor: pointer;
  -webkit-transition: all 0.5s 0s ease;
  -moz-transition: all 0.5s 0s ease;
  -o-transition: all 0.5s 0s ease;
  transition: all 0.5s 0s ease;
}
/*transition: property duration timing-function delay|initial|inherit;*/

.hidden {
  visibility: visible;
  opacity: 0.1;
  max-width: 12%;
}

.hidden:hover {
  visibility: visible;
  opacity: 1;
	max-width: 100%;
}
</style>

<div class="hidden">HOVER ME!</div>

Example 2: css transition

/*CSS Transition Syntax*/
selector {
 transition: property duration timing-function delay|initial|inherit; 
}