index.html

<!DOCTYPE html>
<html lang="fr">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Mise en page trois colonnes</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
        }
        .container {
            display: flex;
            height: 100vh;
        }
        .column {
            flex: 1;
            padding: 20px;
            border: 1px solid #ccc;
        }
        .column:not(:last-child) {
            margin-right: 20px;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="column">
            <p>Colonne 1</p>
        </div>
        <div class="column">
            <p>Colonne 2</p>
        </div>
        <div class="column">
            <p>Colonne 3</p>
        </div>
    </div>
</body>
</html>