<div id="header" class="container">

    <div id="header_nazov" class="flex-item" style="align-self: center;">
        <p>"Onedrive"</p>
    </div>
</div>
<nav class="topnav container_menu" id="myTopnav" style="align-items: center;">
    <a href="/?dano" class="active">Dávid</a>
    <a href="/?daniel">Daniel</a>
    <a href="javascript:void(0);" class="icon" onclick="myFunction()">☰</a>
</nav>