new.html

<!DOCTYPE html>
<html lang="es">
<head>
  <meta charset="UTF-8">
  <title>Enviar un mensaje</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body class="bg-light">
  <div class="container mt-5">
    <div class="card shadow-sm">
      <div class="card-header bg-primary text-white">
        Formulario de contacto
      </div>
      <div class="card-body">
        <form action="/cgi-bin/enviar.cgi" method="post">
          <div class="mb-3">
            <label for="nombre" class="form-label">Nombre</label>
            <input type="text" class="form-control" id="nombre" name="nombre" required>
          </div>
          <div class="mb-3">
            <label for="correo" class="form-label">Correo electrónico</label>
            <input type="email" class="form-control" id="correo" name="correo" required>
          </div>
          <div class="mb-3">
            <label for="mensaje" class="form-label">Mensaje</label>
            <textarea class="form-control" id="mensaje" name="mensaje" rows="4" required></textarea>
          </div>
          <button type="submit" class="btn btn-success">Enviar</button>
        </form>
      </div>
    </div>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>