body {
  background: rgb(200,200,200);
  text-align: center; /* MS-IE will das so zur Zentrierung der Mainbox */
}

.mainbox {
  width: 800px;
  height: 600px;
/*  background-color: orange; */
  background-color: rgb(255,185,1);
  border: blue solid 1px;
  margin: 10px auto; /* Andere wollen das so zur Zentrierung der Mainbox */
}

.headline {
  width: 800px;
  background-color: blue;
}

a.navibox:link {
  display: block;
  float: left;
  width: 160px;
  text-align: center;
  text-decoration:none;
  background-color: blue;
  color: rgb(255,185,1);
}

a.navibox:visited {
  display: block;
  float: left;
  width: 160px;
  text-align: center;
  text-decoration:none;
  background-color: blue;
  color: rgb(255,185,1);
}

a.navibox:hover {
  display: block;
  float: left;
  width: 160px;
  text-align: center;
  text-decoration:none;
  background-color: rgb(255,185,1);
  color: white;
}

.content {
  border-top: blue solid 1px;
  clear: both;
  padding-left: 1em;
  text-align: left;
}