JSFiddle - React, Tailwind, and code Playground

HTML

<header>
<h1 data-text="Centrage d'une répétition">Centrage d'une répétition</h1>
</header>

CSS

header
{
	text-align:center;
  font-size:16px;
}
h1
{
	position:relative;
	font-style:italic;
	color:#ddd;
	font-size:4em;
}
h1:before
{
	content:attr(data-text);
	color:#000;
	position:absolute;
	font-size:.7em;
	white-space:nowrap;
  margin: .3em 0 0 5px;
}