JSFiddle - React, Tailwind, and code Playground

HTML

<div id="upperline">

    <ul>
        <li>our team</li>
        <li>help</li>
        <li>contact</li>
    </ul>
    <p>log in</p>
    <div class="clearfix"></div>
</div>

CSS

#upperline {
  background:brown;
  width:100%;
}

#upperline ul {
  float:left;
}

#upperline p {
  float:right;
}

.clearfix {
  clear:both;
}