My background color for my div is not working

Question

I want to make my element have background #22223b, but my code is not working.

.nav {
  background-color: #22223b;
}

<div class="header">
  <div class="nav">
    <ul>
      <li> <a href="index.html">Home</a> </li>
      <li> <a href="#">About Us</a> </li>
      <li> <a href="#">Start Learning</a> </li>
    </ul>
  </div>

  <div class="account">
    <ul>
      <li> <a href="#">Profile</a> </li>
      <li> <a href="#">Portal</a> </li>
    </ul>
  </div>

Answer 1

The background-color should be visible, if it´s not then there is probably some problem with linking the css file.

I added the styling in a <style> so the styling applies without needing the css file.

<div class="nav">
  <ul>
    <li> <a href="index.html">Home</a> </li>
    <li> <a href="#">About Us</a> </li>
    <li> <a href="#">Start Learning</a> </li>
  </ul>
</div>
<div class="account">
  <ul>
    <li> <a href="#">Profile</a> </li>
    <li> <a href="#">Portal</a> </li>
  </ul>
</div>

<style>
  .nav {
    background-color: #22223b;
  }
</style>