* {    
    margin: 0;
    padding: 0;
}
 
html, body {
height: 100%;
} 
a {color: #000000; text-decoration: none;font-weight: bold; text-align: center; vertical-align: middle;}
a:visited {color: #999999; font-weight: bold;}
a:active {color: #000000;}
a:hover {color: #ffffff;}

#seite {
    position: relative;
    min-height: 100%;
    width: 1000px;
    margin: 0 auto;
    background-color: #ffffff;
}

hr  { border:solid #FFFFFF 3px; height:3px auto;
    position: absolute;
    top: 73px; margin-left: 30.0em; width:376px}

    .karte1 { font-family: Arial,sans-serif;
    position: absolute;
    font-size: 20px;
    font-weight: 200;
    margin-left: 9em;
    margin-top: -5em;
    color: #FFFFFF;
   }
  
    .henze { font-family: Arial,sans-serif;
    position: absolute;
    
    font-size: 40px;
    font-weight: 900;
    margin-left: 12em;
    margin-top: -1.7em;
    color: #FFFFFF;
   } 
    .karte2 { font-family: Arial,sans-serif;
    position: absolute;
    font-size: 20px;
    font-weight: 200;
    margin-left: 20.5em;
    margin-top: -1.3em;
    color: #FFFFFF;
   }  
    .karte3 { font-family: Arial,sans-serif;
    position: absolute;
    font-size: 20px;
    font-weight: 600;
    margin-left: 32.5em;
    margin-top: -1.2em;
    color: #FFFFFF;
   }
   
    .karte4 { font-family: Arial,sans-serif;
    position: absolute;
    font-size: 26px;
    font-weight: 600;
    margin-left: 21em;
    margin-top: 1.7em;
    color: #FFFFFF;
   }

      
header, nav, section, footer {


    display: block;
}
header
{   background-color: #243282; 
    position: absolute;
    top: 0px; width: 100%;
    height: 10em;
    line-height: 15em;
    margin-top: 0em;
    font-family: Arial;
    color: #FFFFFF;      
    
}
nav
{   background-color: green; }
section
{   background-color: #ffffff;
    position: absolute;
    margin-left: 8em;
    margin-right: 4em;
    margin-top: 13.0em;
    font-family: Arial;
    vertical-align: middle;
     }

 }
footer
{   background-color: #243282;
    bottom: 0px; width: 100%;
    height: 2em;
    line-height: 2em;
    
 }
 #box1 {
  position: absolute;
  top: 160px;
  left: 10px;
}
 
#box2 {
  position: absolute;
  top: 160px;
  left: 146px;
} 
 
#box3 {
  position: absolute;
  top: 160px;
  left: 293px;
} 
 
#box4 {
  position: absolute;
  top: 160px;
  left: 396px;
} 

 
#box5 {
  position: absolute;
  top: 160px;
  left: 685px;
} 

 
#box6 {
  position: absolute;
  top: 160px;
  left: 813px;
} 

 
#box7 {
  position: absolute;
  top: 160px;
  left: 908px;
} 

 
#box8 {
    position: absolute;
    top: 10px;
    left: 60px;
    z-index: 1;
} 

.button
{
	font-family: Arial;
	font-weight: bold;
	font-size: 80px; 
   	font-size: 1.10em;

	cursor: pointer;
	padding: 10px;

	border: 1px solid #0404AC;
	-moz-border-radius: 10px; -webkit-border-radius: 10px; border-radius: 10px;

	background: #0404AC;
	background-image: -webkit-gradient(
		linear,
		left bottom,
		left top,
		color-stop(0.20, rgb(000,000,180)),
		color-stop(0.89, rgb(222,222,222))
	);
	background-image: -moz-linear-gradient(
		center bottom,
		rgb(000,000,255) 20%,
		rgb(222,222,222) 89%
	);
}

.button:hover
{
	border: 2px solid #0000bf; 	
}

.round-button {
	width:25%;
}
.round-button-circle {
	width: 100%;
	height:0;
	padding-bottom: 100%;
    border-radius: 50%;
	border:10px solid #cfdcec;
    overflow:hidden;
    
    background: #4679BD; 
    box-shadow: 0 0 3px gray;
}
.round-button-circle:hover {
	background:#30588e;
}
.round-button a {
    display:block;
	float:left;
	width:100%;
	padding-top:50%;
    padding-bottom:50%;
	line-height:1em;
	margin-top:-0.5em;
    
	text-align:center;
	color:#e2eaf3;
    font-family:Verdana;
    font-size:1.2em;
    font-weight:bold;
    text-decoration:none;
}                              
.inhalt {
  
}   
 <!text-decoration: underline>;