.header {
  background-color: #F1F1F1;
  text-align: center;
  padding: 15px;
  margin-left: 100px;
  margin-right: 100px;
}



.topnav {
  overflow: hidden;
  background-color: #333;
  margin-left: 100px;
  margin-right: 100px;
  margin-top: 10px;
}


.topnav a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  
}

.topnav a:hover {
  background-color: #ddd;
  color: black;
}
       #plka { 
  float:left;
  height: 300px;
  width: 300px;
  padding: 5px;
  background:blue;
  color: #1f1a11;
  font-size: 15px;
  margin-left: 100px;
  margin-top: 10px;
  
    }
          #main { 
            
  float: right;
  height: 300px;
  width: 300px;
  padding: 5px;
  background:blue;
  color: #1f1a11;
  font-size: 15px;
  margin-left:300px;
  margin-top: 10px;

    }