Hi ! I don´t understand why my div class="footer" doesnt appear, everthing else seems to work fine. Thx for help !
<!DOCTYPE html>
<html>
<head>
<title>Hauptseite</title>
<meta http-equiv="Content-Type" content="text/html; charset="UTF-8">
<style type="text/css">
html,body{height:100%;margin:0;background-color:#191970;}
.maincontent{position:relative;min-height:100%;margin-left:10%;margin-right:10%;background-image:url(pic1_pixabay.jpg);background-size:100%;background-repeat: no-repeat;}
.frontbox{position:absolute;margin-top:1%;left:1%;right:2%; padding:20px;font-size;text-align:center;background-color:white;opacity:0.5;border:thick solid #4D94FF;border:(255, 255, 255, .5); border-radius: 25px;}
.sidebox{position:absolute;top:40%;left:2%;width: 250px;background-color:white;opacity:0.5;border:thick solid #4D94FF;border-radius: 25px;}
.footer{background-color:black;}
</style>
</head>
<body>
<div class="maincontent">
<div class="frontbox">
<a href="UnserePhilosophie.html">Unsere Philosophie</a> 
<a href="url">Über uns</a> 
<a href="url">Unser Portfolio</a> 
<a href="url">Blog</a> 
<a href="url">Unser Kontakt</a> 
<a href="url">Sample Page</a> 
<a href="url">Tryout Page</a>
</div>
<div class="sidebox">
<ul style="list-style-type:disc">
<li><h1>Updates und Archive</h1></li>
<li><a href="url">Jänner 2015</a></li>
<li><a href="url">Februar 2015</a></li>
<li><a href="url">März 2015</a></li>
<li><a href="url">April 2015</a></li>
<li><a href="url">Mai 2015</a></li>
<li><a href="url">Archive</a></li>
</ul>
</div>
<div class="footer"> Impressum all rights reserved </div>
</div>
</body>
</html>