JSFiddle - React, Tailwind, and code Playground

HTML

<div class="closed-box c--wbb">
	<h2 class="closed-box__title c--bw">Espace utilisateur</h2>
	<ul>
		<li><a class="link--bo" href="#">Mon profil</a></li>
		<li><a class="link--bo" href="#">Messagerie</a></li>
		<li><a class="link--bo" href="#">DĂ©connexion</a></li>
	</ul>
</div>

CSS

*{
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

.closed-box {
    border: 2px solid #0a4393;
    border-radius: 20px;
    margin: 5px 5px 20px 5px;
    padding-bottom: 10px;
    text-align: center;
    box-shadow: 2px 2px 5px #4d4f52;
}

.closed-box__title {
    border-radius: 16px 16px 0 0;
    font-size: 0.975rem;
    margin: 0 0 8px;
    padding: 5px;
    font-weight: 500;
    letter-spacing: .05rem;
}
/*.c--wbb {
	background-color: #fff; 
	color: #0a4393;
}*/
.c--bw {
	background-color: #0a4393; 
	color: #fff; 
}