JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div>Mailbox</div><!-- invisible flex item -->
    <div>Project</div>
    <div>About the Project</div>
    <div>Contact Us</div>
    <div>Mailbox</div>
</div>

CSS

.container { display: flex; }

.container > div:first-child { margin-right: auto; visibility: hidden; }

.container > div:last-child { margin-left: auto; }