@media screen and (max-width:600px) {
   div.float_left_artikel, div.float_right_artikel {width:100%;}
}

@media screen and (min-width:600px) {
  .artikel_details {min-height:540px;background: #FFF url(images/bg_orgel.jpg) no-repeat;background-position: 5px 50px;}
  p {padding:10px;}
}

@media screen and (min-width:800px) {
  .artikel_details {background-position: 20px 50px;}
   div.float_left_artikel, div.float_right_artikel {margin-top:100px;width:30%;}
}