JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mod_navigation">
    <ul class="level_1">
        <li class="submenu bg"><a href="#">materials</a>
            <ul class="level_2">
                <li class="submenu"><a href="#">english</a></li>
                <li class="submenu"><a href="#">deutsch</a></li>
            </ul>
        </li>
        <li class="submenu"><a href="#">kein untermenu</a></li>
    </ul>
</div>

CSS

ul { list-style-type:none; }
li { width:auto; display:block;padding:20px; border:1px solid black; }
a {  }
li.bg:hover { background:url(http://cdns2.freepik.com/fotos-kostenlos/umgekehrtes-dreieck_318-9184.jpg) right top no-repeat; background-size:20px 20px;}