<main>
<div id="outer">
  <div id="logo">
      logo
  </div>
  <ul>
    <li>
      menu1
    </li>
    <li>
      menu2
    </li>
  </ul>
  <div id="auth-div">
      <span>Login</span>
  </div>
</div>
</main>
#outer{
  width: 100%;
  height: 100px;
  background-color:gray;
  display: flex;
}
#logo{
  width: 100px;
  height: 100px;
  background-color:red;
}

ul{
  margin: 0px;
  padding: 0px;
}
li{
  border: 2px solid black;
  display: inline-block;
}

#auth-div{
  width: 100px;
  height: 100px;
  background-color:yellow;
  margin-left: auto;
}

External CSS

  1. https://codepen.io/wangta69/pen/MWqRpbj.css

External JavaScript

This Pen doesn't use any external JavaScript resources.