how do i vertically center text with css 3f

1/*attention, i used this code because i had to center a div with text in another div without text*/
2div{
3  position: relative;
4  top: 25%;
5  bottom: 25%;
6}

1div {
2  height: 100px;
3  line-height: 100px;
4  text-align: center;
5  border: 2px dashed #f69c55;
6}
7
8<div>
9  Hello World!
10</div>