If you’re looking to have just one element on the left and all others on the right, the simplest solution is to use justify-content:flex-end
on the parent element to move all elements to the right and then add margin-right:auto
to the element you want to have on the left
.primary-nav {
display:-webkit-flex;
display:flex;
list-style-type:none;
padding:0;
justify-content:flex-end;
}
.left {
margin-right:auto;
}
<nav>
<ul class="primary-nav">
<li class="left"><a href="#">ListItem1</a></li>
<li class="right"><a href="#">ListItem2</a></li>
<li class="right"><a href="#">ListItem3</a></li>
<li class="right"><a href="#">ListItem4</a></li>
</ul>
</nav>