JSFiddle - React, Tailwind, and code Playground

HTML

<header>
<div id=text>
<h1>Test<font size=10%>.de</font></h1>
<p>danke für eure Hilfe</p>
</div>
  <img src="http://lorempixel.com/400/200/sports/">
</header>

CSS

header {
  display: flex;
  border: 2px solid red;
}
#text {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
#text h1, #text p {
  text-align: center;
}