div{
  margin:5px;
  background:lightblue;
  border-color:blue;
  border-style:solid;
  width:100px;
  height:100px;
  float:right;
}
/**
.caja{
  position:fixed;
  top:0px;
  left:0px;
}
/
/**
.cajapadre{
   position:relative;
   width:300px;
   height:300px;
   background:gray;
}
/