Need help on position

I need some help. My h1 and p aren’t moving and I can’t seem to find the issue, no matter what I do.

<head>

	<title>Nisley Web Design</title>

</head>
	
<style type="text/css">


		body {
		
		background-image:url("http://chicagopolicyreview.org/wp-content/uploads/2016/04/space-4.1-CPR.jpg");
		background-size:cover;
		background-color:#6C3483;
		}

		.topnav {
			overflow:hidden;

		}

		.topnav a{
			
			float:left;
			display: block;
			color: white;
			text-align: center;
			padding: 14px 16px;
			text-decoration: none;
			font-size: 17px;
			font-family:Alegreya Sans Sc;
			color:white;
		}
		
		#h1 {
			 
			  color:#FFFFFF;
			  font-family:Alegreya Sans Sc;
			  font-size:400%;
		}

		.phead {
			  color:#FFFFFF;
			  font-family:Alegreya Sans Sc;
			  font-size:30px;
		}

		.header {
			left:650px;
			
		}
</style>


<link href="https://fonts.googleapis.com/css?family=Alegreya+Sans+SC" rel="stylesheet"> 

<body>
	
	<div class="topnav">
		<a href = "#home">Home</a>
		<a href = "#about">About</a>
		<a href = "#projects">Projects</a>
		<a href = "#contact">Contact</a>
	
	</div>

	<div class="header">
	
		<h1 id="h1"> Nisley Web Design</h1>
		<p class="phead">Innovative Design</p>
		
	</div>

To where should they move? What have you tried?

I’m trying to get them into the center and for them to stay put.

center horizontal or vertical? You could look at this centering guide:

https://css-tricks.com/centering-css-complete-guide/

for horizontal centering you could use text-align

Thank you I’ll take a look.