header center

1div {
2  width: 100%;
3  height: 200px;
4  display: flex;
5  justify-content: center;
6  align-items: center;
7  background: blue;
8}
9
10text {
11  background: orange;
12}
13
14<div>
15   <text>Centered horizontally and vertically</text>
16</div>

1h1{text-align: center;}