Denne VIRKER på mobilen!

En rad, ingen undermenyer.

.holiwicss2 ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333333;
  text-align: center;
}
.holiwicss2 li {
  display:inline-block;
}
.holiwicss2 li a {
  display: block;
  color: white;
  text-align: center;
  padding: 16px;
  text-decoration: none;
}
.holiwicss2 li a:hover {
  background-color: #111111;
}

<div class="holiwicss2">
<ul>
  <li><a href="ex-links.html">Links</a></li>
  <li><a href="ex-lists.html">Lists</a></li>
  <li><a href="ex-menyer.html">Menyer</a></li>
  <li><a href="ex-selectors.html">Selectors</a></li>
</ul>
</div>