ok this time im trying to copy this other website (for those who haven't read my other questions, im doing it just for practice), http://dlang.org/ this one is pretty simple to copy, but im having problem with the content area, if you resize your window browser you can see that the area scales itself but its right and left "border" dont move, only the "center part changes" and i cant freaking do it.

this is my code:
html:
HTML Code:
<!DOCTYPE html>
<html>
<!--.......................Head.....................-->
<head>
	<title>Website</title>
<link rel="stylesheet" type="text/css" href="../../CSS/main css/main.css">
</head>

<!--......................Body......................-->
<body>
	<header>
	<a href="#"><img src="../../css/main css/images/logo.png" id="logo" alt="logo"></a><a href="#" id="logotext">D PROGRAMMING LANGUAGE</a>
		<form>
		<input type="text" id="search">
		<select id="dropdown">
		<option>Entire D Site</option>
		<option>Library Reference</option>
		<option>Newsgroup Archives</option>
		</select>
		</form>
	</header>

<div id="sidebar">
<ul>
<li class="sidebarli"><a href="#" class="sidebara" id="title">D 2.065.0</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Overview</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Features</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Downloads & tools</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Change Log</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Bug Tracker</a></li>
<li class="sidebarli"><a href="#" class="sidebara">FAQ</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Acknowledgments</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Sitemap</a></li>
<li class="sidebarli"><a href="#" class="sidebara">D1 Home</a></li><br>
<li class="sidebarli" id="title">Documentation</li>
<li class="sidebarli"><a href="#" class="sidebara">Tutorial</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Book</a></li>
<li class="sidebarli"><a href="#" class="sidebara">1. Tutorial</a></li>
<li class="sidebarli"><a href="#" class="sidebara">13. Concurrency</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Language Reference</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Library Reference</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Preview New Layout</a></li>
<li class="sidebarli"><a href="#" class="sidebara">How-tos</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Articles</a></li><br>
<li class="sidebarli"><a href="#" class="sidebara" id="title">Visual D</a></li><br>
<li class="sidebarli" id="title">Community</li>
<li class="sidebarli"><a href="#" class="sidebara">Forums</a></li>
<li class="sidebarli"><a href="#" class="sidebara">GitHub</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Wiki</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Review Queue</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Third Party Packages</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Twitter</a></li>
<li class="sidebarli"><a href="#" class="sidebara">Links</a></li>
</ul>	
</div>

<div id="content"></div>
<a href="#" id="rightlink">Tweets by @D_Programming</a>
</body>
</html>
this is my css:
Code:
body 						        {background-image: url(images/background.jpg);
							background-repeat: no-repeat;
							background-color: #1F252B;
							margin: 0px;
							width: 100%;
							min-width: 730px;}


header 						{width: 100%;
							min-width: 976px;}


#logo						        {float: left;
							margin-left: 16px;
							margin-top: 3px;}


#logotext					        {color: white;
							text-decoration: none;
							font-size: 25px;
							margin-left: 10px;
							margin-top: 65px;
							float: left;}


#search						{float: right;
							border-radius: 10px;
							margin-top: 35px;
							margin-right: 130px;
							width: 160px;}


#dropdown					        {margin-top: -38px;
							float: right;
							margin-right: 130px;
							width: 190px;
							height: 18px;
							clear: left;}


.sidebarli					        {color: darkgrey;
							list-style: none;
							margin-top: 4px;}


.sidebara					        {color: darkgrey;
							text-decoration: none;
							border-bottom: 1px dotted darkgrey;}


ul 							{float: left;
							padding: 0px;
							margin-left: 40px;
							margin-top: 0px;}



#title						        {font-size: 25px;
							margin-left: -10px;
							border-bottom: 1px dotted darkgrey;}



#content 					       {background-color: white;
							width: 63%;
							margin-right: 100px;
							height: 1300px;
							float: left;
							border: 4px solid lightgrey;
							margin-left: 10px;}


#rightlink					        {float: right;}