JSFiddle - React, Tailwind, and code Playground

HTML

<div class="flex-div">
  It's no problem to center<br />multiple lines of text
</div>

<div class="flex-div"><img src="http://www.web-plus-plus.com/Images/Articles/vertical-centering-elements-html/cat.png" /></div>

CSS

.flex-div {
  display: flex;
  width: 400px;
  height: 120px;
  justify-content: center;
  align-items: center;
  background-color: #f0fff0;
  border: solid 1px lightgray;
}