What do I add to my CSS code to make this happen?

I am learning about <ul> being floated to the left with navigation items in the nav bar. When running the code…

<!DOCTYPE html>
<html>
<head>
<style>
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

li {
  float: left;
}

li a {
  display: block;
  padding: 8px;
  background-color: #dddddd;
}
</style>
</head>
<body>

<ul>
  <li><a href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li><a href="#contact">Contact</a></li>
  <li><a href="#about">About</a></li>
</ul>

<p><b>Note:</b> If a !DOCTYPE is not specified, floating items can produce unexpected results.</p>
<p>A background color is added to the links to show the link area. The whole link area is clickable, not just the text.</p>
<p><b>Note:</b> overflow:hidden is added to the ul element to prevent li elements from going outside of the list.</p>

</body>
</html>

How do I make the <ul> and <li> extend the same background color of grey until the end of the entire width of the page. If the code above is executed, the gray background only lasts as long as there are <li>s’ to fill it.

Hi! You can create a div around the ul, and add the property “background color” to the div:

<!DOCTYPE html>
<html>
<head>
<style>
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

li {
  float: left;
}

li a {
  display: block;
  padding: 8px;
  
}
  
  .example {
      background-color: #dddddd;
  }

</style>
</head>
<body>
<div class="example">
<ul>
  <li><a href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li><a href="#contact">Contact</a></li>
  <li><a href="#about">About</a></li>
</ul>
  </div>
<p><b>Note:</b> If a !DOCTYPE is not specified, floating items can produce unexpected results.</p>
<p>A background color is added to the links to show the link area. The whole link area is clickable, not just the text.</p>
<p><b>Note:</b> overflow:hidden is added to the ul element to prevent li elements from going outside of the list.</p>

</body>
</html>