body{
  background-color: lightgrey;
}
iframe{
  margin : 20px;

  border-radius: 15px;
}
.topnav {
  background-color: #333;
  overflow: hidden;
  border-radius: 0px 0px 15px 15px;
}
.topnav a {
  float: left;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}
.topnav a:hover {
  background-color: #CCDB2B;
  color: black;
}
.active{
  background-color: darkgreen;
}
.header{
  margin-top: 1%;
background-color: white;
width: 80%;
margin-left: auto;
margin-right: auto;
box-shadow: 10px 10px 5px grey;
border-radius: 15px;
}
.logo{
  padding: 15px;
}
.main{
/* Hintergrund Bild für Main Bereich mit logo */
  background-image: url("../img/bg_man.jpg");
  height: 77.3vh;
  margin-top: 1%;
  background-color: white;
  width: 80%;
  margin-left: auto;
  margin-right: auto;
  box-shadow: 10px 10px 5px grey;
  border-radius: 15px;
}