@media (max-width: 767px) {
  .px1200 {
    visibility:hidden;
  }  
  .px970 {
    visibility:hidden;
  }  
  .px750 {
    visibility:hidden;
  }  
  .mini {
    visibility:visible;
  }   
}

@media (min-width: 768px) and (max-width: 991px) {  
  .px1200 {
    visibility:hidden;
  }     
  .px970 {
    visibility:hidden;
  }  
  .px750 {
    visibility:visible;
  }  
  .mini {
    visibility:hidden;
  }    
}

@media (min-width: 992px) and (max-width: 1200px) {
  .px1200 {
    visibility:hidden;
  }
  .px970 {
    visibility:visible;
  }  
  .px750 {
    visibility:hidden;
  }  
  .mini {
    visibility:hidden;
  }     
}

@media (min-width: 1200px) {
  .px1200 {
    visibility:visible;
  }
  .px970 {
    visibility:hidden;
  }  
  .px750 {
    visibility:hidden;
  }  
  .mini {
    visibility:hidden;
  }     
}