Header.php

<header>
    <div class="container">
        <div class="row">
            <!-- Begin Navigation-->
            <nav class="navbar fixed-top navbar-expand-lg navbar-dark bg-dark">
                <a class="navbar-brand" href="index.php">
                    <img src="Images/Logos/Schuber_Lampen_Logo_No_Text.png" width="30" height="30" class="d-inline-block align-top" alt="">
                    Schuber Lampen
                </a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" data-target="language" aria-controls="navbarSupportedContent" aria-controls="language" aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                </button>
                
                <div class="collapse navbar-collapse col-9" id="navbarSupportedContent">
                    <ul class="navbar-nav mr-auto">
                        <li class="nav-item">
                            <a class="nav-link" href="Produkte.php">Produkte</a>
                        </li>   
                        <li class="nav-item">
                            <a class="nav-link" href="SmartSchuber.php">SmartSchuber™</a>
                        </li>
                        <li class="nav-item dropdown">
                            <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                                Über uns
                            </a>
                            <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                                <a class="dropdown-item" href="HerstellungUndDesign.php">Herstellung und Design</a>
                                <a class="dropdown-item" href="SchuberHolding.php">Schuber Holding</a>
                                <a class="dropdown-item" href="Organisation.php">Organisation</a>
                            </div>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="Kontaktformular.php">Kontaktformular</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="Dienstleistungen.php">Dienstleistungen</a>
                        </li>
                    </ul>
                </div>
                <div class="navbar-nav flex-row ml-md-auto d-none d-md-flex" id="language">                    
                    <li class="nav-item">
                        <a class="nav-link" href="login.php">Login</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link" href="registrieren.php">Registrieren</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link" href="Warenkorb.php"><i class="fas fa-shopping-cart"></i></a>
                    </li>
                </div>
            </nav>
            <!-- Ende Navigation-->
        </div>
    </div>
</header>