.picture
{
   background-size: 100% 100%;
   display: none;
   position: absolute;
   top: 0px;
   left: 0px;
   background-repeat: no-repeat;
   background-position:center center; 
   width:100%;
   height: 100%;
   z-index: -1;
}
.prima
{
  display: block;
}
.slide
{
  display: none;
}
.navbar
{
  display: none;
  position: absolute;
  bottom: 8px;
  right: 8px;
  height: 48px;
  z-index: 1;
}