<div class="center">
  <h1>I am centered vertically</h1>
</div>
.center {
  border: 5px solid #1a73e8;
  display: flex;
  flex-wrap: wrap;
  align-content: center;
  padding: 10px;
  max-width: 550px;
  height: 300px;
}

h1 {
  background-color: #006bee;
  color: #fff;
  padding: 10px;
  flex-grow: 1;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.