JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="Navigation">
    <li><a href="About.html">About</a></li>
    <li><a href="Contact.html">Contact</a></li>
    <li><a href="Contact.html">Contact</a></li>
    <li><a href="Contact.html">Contact</a></li>
    <li><a href="Contact.html">Contact</a></li>
    <!-- ... -->
    <li class="stretch"></li>
</ul>

CSS

#Navigation
{
    list-style-type: none;
    text-align: justify;
    height: 21px;
    background: #ccc
}

#Navigation li
{
    display: inline
}
#Navigation .stretch {
    display: inline-block;
    width: 100%;
    
    /* if you need IE6/7 support */
    *display: inline;
    zoom: 1
}