Hello my problem here is probably a really easy fix but I have no idea.

Code:
<html>
	<head>
	<link rel="shortcut icon" href="paint-splat.png"> 
	<!--defines the background image for the page--> 
		<style> 
			body 
			{
			background-image:url(start_screen.png);
			background-position:relative; 
			background-repeat:no-repeat;
			}
		</style> 
		<title> TraLab | Home</title> 
	</head>
	<body> 
		<!--Creates the section of the page which can be drawn on with javascript--> 
		<canvas id="myCanvas" width="1000" height="600">If you only see a blue backround please use a broswer that supports HTML5</canvas> 
		<script> 
			//get the element that will be edited with javascript
			var $myArt = document.getElementById("myCanvas");
			//import the two dimensional graphics library and assign it to a variable 
			var $myBook = $myArt.getContext("2d"); 
			$myBook.fillStyle="#00A01C";
			$myBook.fillRect(800,430,60,60); 
			$myBook.stroke(); 
			$myBook.beginPath();
			$myBook.moveTo(810,440);
			$myBook.lineTo(810,470); 
			$myBook.stroke(); 
		</script> 
		
	</body>

The problem is when I create the line with lineTo() it is not opaque and if I make the line white it is never the same shade of white as the background. I tried using hexidecimal colors but it still didn't work.