double border color css

1.double-border {
2  display: block;
3  clear: both;
4  background: red;
5  border: 5px solid yellow;
6  outline: 5px solid blue;
7  transition: 0.7s all ease-in;
8  height: 50px;
9  width: 50px;
10}
11.double-border:hover {
12  background: yellow;
13  outline-color: red;
14  border-color: blue;
15}
16<div class="double-border"></div>