[CSS/HTML] Kriege zwei elemente nicht nebeneinander

<?php
$result = $handle->query("SELECT * FROM users");
$gesamte_anzahl = $result->rowCount(); 	
$ergebnisse_pro_seite = 10;
$gesamt_seiten = ceil($gesamte_anzahl/$ergebnisse_pro_seite); 
if (empty($_GET['seite_nr'])) {
	$seite = 1;
} else {
	$seite = $_GET['seite_nr'];
	if ($seite > $gesamt_seiten) {
		$seite = 1;
	}
} 
$limit = ($seite*$ergebnisse_pro_seite)-$ergebnisse_pro_seite;


$query = "SELECT * FROM users LIMIT $limit, $ergebnisse_pro_seite";
$anzahl=0;
$body .= '<div style="opacity: 0.96; margin-left: 200px; padding-left: 50px; width: 100%; float:right;"  >';
$body .= '<table class="table"> 
<tr>
<th>#</th>
<th>Username</th> 
<th>Adminlevel</th>
<th>Level</th> 
<th>Geld | Bank</th>
</tr>
';
foreach ($handle -> query($query) as $row) {	
$body .= "
	  <tr>
		<th scope="row">".$row['id']."</th>
		<td>".$row['Name']."</td>
		<td>".$row['AdminLevel']."</td>
		<td>".$row['Level']."</td>
		<td>".$row['Money']." | ". $row['Bank']."</td>
	  </tr>
	  ";
	$anzahl++;
}
$body .= '</table>';


$body .= '<ul class="pagination">';
if($seite > 1) {
	$backward = $seite-1;
	$body .= '<li>
	  <a href="index.php?page=adminpanel&cmd=playerlist&seite_nr='.$backward.'" aria-label="Previous">
		<span aria-hidden="true">«</span>
	  </a>
	</li>';
} else  $body .= '<li class="disabled">
	  <a href="#" aria-label="Previous">
		<span aria-hidden="true">«</span>
	  </a>
	</li>';
for ($i=1; $i<=$gesamt_seiten; ++$i) {
	if ($seite == $i) {
		$body .=  '<li class="disabled"><a href="index.php?page=adminpanel&cmd=playerlist&seite_nr='.$i.'">'.$i.'</a></li>';
	} else {
		$body .=  '<li><a href="index.php?page=adminpanel&cmd=playerlist&seite_nr='.$i.'">'.$i.'</a></li>';
	}
}
if($seite < $gesamt_seiten) {
	$forward = $seite+1;
$body .= '<li>
  <a href="index.php?page=adminpanel&cmd=playerlist&seite_nr='.$forward.'" aria-label="Next">
	<span aria-hidden="true">»</span>
  </a>
</li>';

} else  $body .= '<li class="disabled">
	  <a href="#" aria-label="Next">
		<span aria-hidden="true">»</span>
	  </a>
	</li>';
$body .= '</div></div></div>';
?>

$body .= '<div class="leftNavi"><ul class="nav nav-tabs nav-stacked">';
		$body .= '<li class="nav-header" style="margin-left: 15px; margin-top: 5px;">Navigation</li>';
			if(isset($_SESSION['name'])) {
					$body .= '<li role="presentation"><a href="#">Profil</a></li>';
				if($results['AdminLevel'] > 0) {
					$body .= '<li role="presentation"><a href="index.php?page=adminpanel&cmd=playerlist">Spielerliste</a></li>';
				}
			} else {
				echo '<li role="presentation" class="active"><a href="index.php?page=login">Anmelden</a></li>';
			}
		  $body .= '
		  <li role="presentation"><a href="#">Nachrichten</a></li>

		</ul></div>';

$body .= '<div class="mainContainer">'; //Ganz am Anfang meiner ersten Datei.
$body .= '<div class="content" style="opacity: 0.96; float: left; width: 100%;">';
.mainContainer {
	display:table;	
	float:right;
}
.mainContainer #content {
	display:table-cell;
}


.leftNavi {
	width: 200px;
	height: 500px;
	background-color:#232323;	
	float:left;
}
.leftNavi .nav-header { color: #FFFFFF; font-size: 15px; font-style:italic; }
.leftNavi .nav-tabs.nav-stacked > li > a { border: 0; border-bottom: 1px solid #232323; }
.leftNavi .nav-tabs.nav-stacked > li > a:hover { background-color: #2c2c2c; color: #fff; border-bottom-color: #232323; }

<?php
$titel = "Startseite";


$query = 'SELECT * FROM `ucp_blog` ORDER BY `id` ASC LIMIT 3';
$anzahl=0;
$body .= '        <div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main" style="top: 30px;">
                          <h1 class="page-header">
                    Startseite
                </h1>';
foreach ($handle -> query($query) as $row) {

	$body .= '
		<h2>
			<a href="#">'. $row['titel']. '</a>
		</h2>
		<p class="lead">
			<small>Geschrieben von <a href="index.php">'.$row['writer'].'</a></small>
		</p>
		<p><span class="glyphicon glyphicon-time"></span> '.$row['writer'].'</p>
		<p>'. $row['text'] .'</p>
		<a class="btn btn-primary" href="#">Mehr <span class="glyphicon glyphicon-chevron-right"></span></a>


		<hr>';
	$anzahl++;
}
$body .= '</div>';
?>

<div class="col-sm-3 col-md-2 sidebar">
      <ul class="nav nav-sidebar">
        <li class="active"><a href="#">Overview <span class="sr-only">(current)</span></a></li>
        <li><a href="#">Reports</a></li>
        <li><a href="#">Analytics</a></li>
        <li><a href="#">Export</a></li>
      </ul>
      <ul class="nav nav-sidebar">
        <li><a href="">Nav item</a></li>
        <li><a href="">Nav item again</a></li>
        <li><a href="">One more nav</a></li>
        <li><a href="">Another nav item</a></li>
        <li><a href="">More navigation</a></li>
      </ul>
      <ul class="nav nav-sidebar">
        <li><a href="">Nav item again</a></li>
        <li><a href="">One more nav</a></li>
        <li><a href="">Another nav item</a></li>
      </ul>
    </div>

.sidebar {
  display: none;
}
@media (min-width: 768px) {
  .sidebar {
    position: fixed;
    top: 200px;
    bottom: 0;
    left: 0;
    z-index: 1000;
    display: block;
    padding: 20px;
    overflow-x: hidden;
    overflow-y: auto; /* Scrollable contents if viewport is shorter than content. */
    background-color: #f5f5f5;
    border-right: 1px solid #eee;
  }
}


/* Sidebar navigation */
.nav-sidebar {
  margin-right: -21px; /* 20px padding + 1px border */
  margin-bottom: 20px;
  margin-left: -20px;
}
.nav-sidebar > li > a {
  padding-right: 20px;
  padding-left: 20px;
}
.nav-sidebar > .active > a,
.nav-sidebar > .active > a:hover,
.nav-sidebar > .active > a:focus {
  color: #fff;
  background-color: #428bca;
}