.kopf
	{
		width: 100%;
		height: 50px;    
		background: rgb(230,230,230);
		text-align: center;
		margin-top: auto;
	}
	
.links
	{
		float: left;
		width: 20%;
		height: 500px; 
		background-color: #00ff00; 
	 } 

.rechts 
	{
		float: right;
		width: 80%;
		height: 500px; 
		background-color: #0000ff; 
	}

.clear 
	{ 
		clear: both;
	}

.unten
	{
		width: 100%;
		height: 50px;    
		background: #ff0000;
		text-align: center;
	}

		
body																
	{
		background-color: #c5c5c5;
		width: 80% ;
		margin: auto;
	}
	
table
	{
		margin-left: auto;
		margin-right: auto;
		border: 1px solid black;
		border-spacing : 0px ;
	}
					
td
	{
		width: 100px;
		height: 100px;
		background : grey;				
	}
					
tr:nth-child(even) > td:nth-child(odd)
	{
		background: black; 
	}
					
tr:nth-child(2n+1) > td:nth-child(2n)
	{
		background: black; 
	}
															
#beschriftung_seite
	{
		width: 18px;
		height: 100px;
		color: white;
		background: #5555ff;
		text-align: center;
	}
										
#beschriftung_unten
	{
		width: 100px;
		height: 18px;
		color: white;
		background: #5555ff;
		text-align: center;
	}