css dropdown

1<style>
2.dropdown {
3  position: relative;
4  display: inline-block;
5}
6
7.dropdown-content {
8  display: none;
9  position: absolute;
10  background-color: #f9f9f9;
11  min-width: 160px;
12  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
13  padding: 12px 16px;
14  z-index: 1;
15}
16
17.dropdown:hover .dropdown-content {
18  display: block;
19}
20</style>
21
22<div class="dropdown">
23  <span>Mouse over me</span>
24  <div class="dropdown-content">
25    <p>Hello World!</p>
26  </div>
27</div>