my goal is to create something like this :enter image description here So an area where I can put a form for authentification or create an account. I already created a form in php which is linked to my database like this

 <form action="connection.php" method="post">
    <div class="form-group">
        <label >Nom</label>
        <input name = nom>
    </div>
    <div class="form-group">
        <label >Prénom</label>
        <input name = prenom>
    </div>
    <div class="form-group">
        <label >Email</label>
        <input name = mail>
    </div>
    <div class="form-group">
        <label >Numéro de telephone</label>
        <input name = tel>
    </div>
    <div class="form-group">
        <label >mot de passe</label>
        <input type=password id="inputPassword" placeholder="Password"">
    </div>
    <button type="submit" class="btn btn-primary" name="add">Creer son compte</button>

function inscription($db,$nom,$prenom,$mail,$tel,$mdp){
    try{
    $request_client = "INSERT INTO client (nom, prenom, mail, tel, mdp) VALUES (:nom, :prename, :email, :phone,:pass);";
    $statement_client = $db->prepare($request_client);
    $statement_client->bindParam(':nom', $nom);
    $statement_client->bindParam(':prename', $prenom);
    $statement_client->bindParam(':email', $mail);
    $statement_client->bindParam(':phone', $tel);
    $statement_client->bindParam(':pass', $mdp);
    $statement_client->execute();
    }
    catch (PDOException $exception)
  {
  error_log('Request error: '.$exception->getMessage());
  return false;
  }
}

Is there something in boostrap or css or even js which can make me creat this blue area ?