I am trying to follow the box model style of website design showed in thenewboston's video, but when I apply the float element and refresh my site shows up blank.
Here is a snippet of my CSS and HTML.
CSS
* {
   margin: 0px;
   padding: 0px;
}
  h2 { 
    font: bold 23px "Times New Roman";
    color: black;
}
  h3 { 
  font: italic 16px "Times New Roman";
 }
 header, section, footer, aside, nav, article, hgroup {
 display: block;
 }
 body { 
  text-align: center;
 }
#page_wrapper {
    width: 1000px;
    margin: 20px auto;
    text-align: left;
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-box-flex: 1;
  }
#top_header {
    font-family: "Times New Roman";
    font-size: 23px;
    padding: 10px; 
    font-decoration: italic;
    color: white;
    background: #454545;
 }
 #top_menu {
     background: #454545;
     color: white;
     padding: 3px;
     border: 1px solid black;
     font: italic 20px Georgia;
 }
 #top_menu li { 
     display: inline-block;
     list-style: none;
     padding: 5px;
     font: italic 14px "Times New Roman";
     color: white;
 }
#new_div {
    display: -webkit-box;
    -webkit-box-orient: horizontal;
  }
 #page_section {
 float: left;
 width: 660px;
 margin: 30px;
 border: 1px solid black;
 font: 15px "Times New Roman";
 }
 #page_aside {
  float: left;
  width: 220px;
  margin: 20px 0px;
  padding: 30px;
  border: 1px solid black;
  background: #DCE1E3;
  text-align: center; 
  font: 15px "Times New Roman";
  }
HTML
 <head>
<meta charset="utf-8" />
<title>A Website</title>
<link href="styles1.css" type="text/css" rel="stylesheet" /> 
</head>
<body>
<div id="page_wrapper">
<header id="top_header">
<h1>A Website</h1>
</header>
<nav id="top_menu">
<ul style="list-style-type:none">
<li><a href="http://www.google.com">Home</a></li>
<li><a href="http://www.google.com">About</a></li>
<li><a href="http://www.google.com">Portfolio</a></li>
<li><a href="http://www.google.com">Contact</a></li>
</ul>
</nav>
<div id="new_div">
<section id="page_section">
<article>
<header>
<hgroup>
<h2>I am an H2 Article Title</h2>
<h3>I am an H3 Article Subtitle</h3>
</hgroup>
</header><br><br>
<p>Hi I'm a paragraph. La La La !</p> <br><br>
</p>
</article>
</section>
<aside id="page_aside">
<h4>Updates for the Website</h4><hr><br>
<p>- I'm an Update</p><br>
<p>- So Am I!</p>
</aside></div><br>
</div>
</body>
</html>
 
     
     
    