Hi I've got a parent div of 100% inside there is a child div with width size in px but when I make the browser smaller the parent div stop been 100% and becames smaller than the child div is there a way I can make the parent div to always be 100% of the browser

here my code
Code:
<!DOCTYPE HTML>
<head>
<style type="text/css">
#parent_div {background-color:red; width:100%; padding:10px;}
.child_div {background-color:yellow; width:884px; margin:auto; clear:both; padding:10px;}
</style>
</head>
<body>
   


<div id="parent_div">
	<div class="child_div">
		<p>Compass Group UK &amp; Ireland Limited ("We") are committed to protecting and respecting your privacy.</p>
    </div>
</div> 


</body>
</html>