Éditeur Tryit de W3Schools

<!DOCTYPE html>
<html>
<head>
<style>
body {
marge: 0;
padding: 0;
}

h1 {
margin-top: 60px;
marge-gauche: 10px;
}

h2, p {
marge: 10px;
}

ul {
list-style-type: none;
marge: 0;
padding: 0;
débordement: caché;
couleur de fond: #333333;
position: fixe;
haut: 0;
largeur: 100%;
}

ul li {
flottant: gauche;
}

ul li a {
afficher: bloc;
couleur: blanc;
text-align: center;
padding: 14px 16px;
text-decoration: none;
}

ul li a:hover:not(.active) {
couleur-de-fond: #111;
}

ul li a.active {
couleur de fond: #D74444;
}
</style>
</head>
<body>

<ul>
 <li><a class="active" href="#home">Accueil</a></li>
 <li><a href="#news">Nouvelles</a></li>
 <li><a href="#contact">Contact</a></li>
 <li><a href="#about">À propos</a></li>
</ul>

<h1>Barre de navigation fixe en haut</h1>
<h2>Faites défiler cette page pour voir l'effet ! La barre de navigation restera en haut de la page pendant le défilement.</h2>

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</body>

</html>