body {
  color: black;
  background-color: white;
  
}

#wrapper {
	position: relative; /* wichtig! */
	background-color: orange;
	width: 900px;
	margin: auto;
}


#heading {
  position: absolute;
  width: 900px;
  top: 20px;
  background-color: #97dec7;
  border-width: 5px;
  border-color: #3489eb;
  border-style: solid;
}

#aside {
  position: absolute;
  top: 80px;
 
  width: 25%;
  height: 300px;
  background-color: #ccccff;
  border-width: 7x;
  border-color: #3489eb;
  border-style: solid;
}
#main {
  position: absolute;
  top: 80px;
  left: 30%;
  width: 70%;
  height: 300px;
  background-color: green;
  border-width: 5px;
  border-color: #3489eb;
  border-style: solid;
 
 }
 
 #footer {
  position: absolute;
  top: 400px;
  width: 400px;
  background-color: orange;
  border-width: 5px;
  border-color: #3489eb;
  border-style: solid;
}